12. Equipment Installation

Chapter Description

This chapter provides information, illustrations, advantages and disadvantages of various pump types and groundwater monitoring equipment. This chapter covers the requirements and exemptions for the installation of equipment in test holes and dewatering wells and provides information on the installation of equipment in wells completed above ground and in well pits. The requirements listed in this chapter do not apply to shallow works or other exempted wells discussed in Chapter 3: Exemptions: Wells, Activities & Experienced Professionals.

Regulatory Requirements – Equipment Installation

Relevant Sections – The Wells Regulation

Exemptions – Section 1.0.2
Installation of Equipment – Sections 15.2 to 15.3
Venting – Section 15.1
Surface Drainage – Section 12.3
Flush Mount Covers – Subsection 13(11)
Well Pits – Subsection 12(7.1) and 12(9) paragraphs 1, 2 and 3, subsection 13(14) and Section/Subsection 14.5, 14.5(3)

The Requirements – Plainly Stated – Installing the Equipment

Reminder: The regulatory exemptions regarding test holes and dewatering wells allow for well technicians, engineers and geoscientists to use their professional expertise to design and install test holes and dewatering wells on a case by case basis, thereby enabling the testing, sampling or dewatering of various groundwater intervals.

Requirements for the Records of Site Condition regulation are provided in the following sections of this chapter:

• Sampling and Monitoring Equipment
• Groundwater Sampling
• Groundwater Level and Other Monitoring Equipment
• Well Caps and Covers
• Creating and Filling the Well Pit’s Annular Space

Relevant Additional Regulations or Legislation

Ontario Regulation 153/04 as amended (Records of Site Condition) made under the Environmental Protection Act, R.S.O. 1990, Chapter E. 19

Ontario Regulation 164/99 as amended (Electrical Safety Code) made under the Electricity Act, 1998, S.O. 1998, Chapter 15, Schedule A

Ontario Regulation 632/05 as amended (Confined Spaces) made under the Occupational Health and Safety Act, R.S.O. 1990, Chapter O. 1

Ontario Regulation 213/91 as amended (Construction Projects) made under the Occupational Health and Safety Act, R.S.O. 1990, Chapter O. 1

Relevant Standards

ASTM D 5088-02 (Reapproved 2008) – "Standard Practice for Decontamination of Field Equipment Used at Waste Sites." (DOI: 10.1520/D5088-02R08)^{footnote 1[1]}

ASTM D 5092-04e1 – "Standard Practice for Design and Installation of Ground Water Monitoring Wells." (DOI: 10.1520/D5092-04E01)^{footnote 1[1]}

ASTM D 5608-01 (Reapproved 2006) – "Standard Practices for Decontamination of Field Equipment Used at Low Level Radioactive Waste Sites" (DOI: 10.1520/D"5608-01R06)^{footnote 1[1]}

ASTM D 5787-95 (Reapproved 2009) – "Standard Practice for Monitoring Well Protection" (DOI: 10.1520/D5787-95R09)^{footnote 1[1]}

ASTM D 5978-96 (Reapproved 2005) – "Standard Guide for Maintenance and Rehabilitation of Ground-Water Monitoring Wells" (DOI: 10.1520/D5978-96R05)^{footnote 1[1]}

Relevant Guidelines

Guidance on Sampling and Analytical Methods for Use at Contaminated Sites in Ontario, Ontario Ministry of Environment and Energy, Standards Development Branch December, 1996.

Preferred Operating Practices for Borehole/Monitoring Well Installation and Associated Soil/Groundwater Sampling at Hydrocarbon Impacted Sites, Imperial Oil, May 15, 2002

Australian Drilling Industry Training Committee Limited, Drilling – The Manual of Methods, Applications and Management. CRC, Lewis Publishers, Boca Rata, New York, 1996

Monitoring Well Design, Installation and Documentation at Hazardous, Toxic, and Radioactive Waste Sites, Report A301204. US Army Corps of Engineers. 1998

The Safety Manual for Well Technicians. (Supplemental course material). Fleming College, School of Continuing Education and Skilled Trades. 2008

WSC Performance Standards and Recommended Installation Procedures for Sanitary Water Well Pitless Adapters, Pitless Units, and Well Caps, PAS-97(04), 2004

Key Concepts

What to Consider When Installing Equipment

It is important to consider the protection of health, safety and the environment when installing equipment. Unless exempt, the following requirements and considerations are relevant to the installation of equipment:

1. Anything that is put into the well must not impair the quality of the water,
2. The purpose for installing equipment (e.g., measuring),
3. The sanitary well seal, cover or cap must be properly secured on the top of the test hole or dewatering well to prevent the entry of surface water and other foreign materials,
4. Other than sample collection, contaminants should not enter or exit the well during any monitoring or sampling events,
5. Any space around the waterline through the side of the casing or through the top of the casing must be made watertight, and
6. In the case where a pump is installed in a dewatering well, for example, the final grade of the ground surface must allow for the proper height of casing and must not allow ponding of water in the vicinity of the well.

Reminder: Chapter 3: Exemptions: Wells, Activities & Experienced Professionals provides clarification when the requirements in bullets 2 to 6 do not apply.

Sampling and Monitoring Equipment

The purpose of groundwater sampling and monitoring programs is to obtain accurate samples and measurements that are representative of the groundwater or aquifer in a study area. Inconsistent and biased samples and measurements lead to incorrect interpretations and wrong remedial actions.

Depending on the purpose of the program or study, there are various types of equipment for field measurements (e.g., water level meters, flow-through cells, pH meters, conductivity meters, and temperature meters) and sampling (e.g., passive samplers, bailers, inertial lift pumps, bladder pumps, and submersible pumps).

Connections to Wells

Connections may be required for a test hole or dewatering well to function properly. Connections can be made above and below the ground surface to accommodate waterlines or instrumentation to enter a well, for instance. Any connection must be made watertight. This reduces the risk of contamination of both the well and the aquifer.

Venting the Well

The purpose of the vent is to allow the well to breathe, which allows equalizing pressures (i.e., when water is drawn out, air goes in so the column of water is at atmospheric pressure at all times), and allow the safe venting of natural gas and other gases to the outside atmosphere.

Well Caps & Covers

Proper covering of the test hole or dewatering well prevents the entry of foreign materials into the groundwater. Proper capping and covering will also help to assure that groundwater quality samples are not biased by surface water, contamination, or other foreign materials. Securing the test hole or dewatering well is a safeguard against unauthorized entry into the well, vandalism or tampering. Securing the well includes ensuring that the well cap, seal or cover is on properly and may include the use of a protective cover with locking cap, barriers or fences. For information on securing the well refer to Chapter 9: Completing the Test Hole or Dewatering Well Structure.

Casing Height & Mounding

The purpose of the minimum casing height is to prevent water from entering the well and to allow for venting. The purpose of mounding is to ensure that surface runoff does not pond in the vicinity of the well and infiltrate into the well. When installing or connecting equipment, the minimum casing height must be maintained and any mounding around the well that has been disturbed must be restored to meet the drainage requirements found in the "Plainly Stated" section of this chapter. This does not apply if the equipment installation is exempt from the Wells Regulation (e.g., measuring the water level in a well using a water level meter) or if the equipment is installed in an exempted well (see Chapter 3: Exemptions: Wells, Activities & Experienced Professionals for further information).

Well Pits

A well pit is an enclosed structure located at and below the ground surface that houses the top of the well and any associated pumping equipment. The top of the well casing extends out of the floor of the well pit.

A flush-mounted well pit (vault), used in test hole construction, is a type of well pit.

A well pit, other than a flush-mounted well pit, is usually installed at or near the time of pump and associated equipment installation in the well.

The well pit can:

• protect the well from outside environmental conditions such as freezing of waterlines and the entry of surface water runoff and other foreign materials, and
• allow access to the well and pumping system from the ground surface for maintenance and repair

Health and Safety Considerations: Trenches, Confined Spaces and Electrical

The safety manual from the well drilling continuing education course provides details regarding safety when excavating or working in trenches and confined spaces, along with precautions for working with or around electrical lines. This manual is available from Sir Sanford Fleming College (see the Resources section of this manual). It is recommended that these guidelines and the Occupational Health and Safety Act and its relevant regulations be reviewed prior to taking on any related tasks. Failure to be aware of the surroundings and to follow appropriate safety procedures could result in serious injury or death.

Sampling and Monitoring Equipment

The Wells Regulation requires a person constructing a test hole or dewatering well to meet the following, unless an exemption is provided in the Plainly Stated section of this chapter or in Chapter 3: Exemptions: Wells, Activities & Experienced Professionals.

Wells Regulation: Any equipment installed in a test hole or dewatering well must be clean as required by the Wells Regulation.

Reminder: All equipment installed in a test hole or dewatering well must not cause or have the potential to cause impairment to the water in the well or the groundwater as required under subsection 30(1) of the Ontario Water Resources Act.

Reminder: For further information on what activities or wells are exempt and what activities and wells require licensing, see Chapters 3: Exemptions: Wells, Activities & Experienced Professionals and Chapter 4: Well Contractors & Well Technicians – Licences, Responsibilities & Exemptions.

Records of Site Condition Regulation: Starting on July 1, 2011, amendments to O. Reg. 153/04 came into force and apply to phase two environmental site assessments (ESAs) conducted in support of records of site conditions (RSCs). For any such RSC submitted on or after this date where, for example, an existing developed monitoring well is used, the following requirements apply:

Requirements Related to Equipment Installation & Use

• The qualified person must ensure that there is a sampling and analysis plan that includes a quality assurance and quality control (QA/QC) program. The QA/QC program must include a requirement that all non-dedicated sampling and monitoring equipment be cleaned following each use.
• Where sampling of groundwater is being undertaken to demonstrate if the applicable site condition standard for a contaminant has been met or not, the qualified person must ensure that:
  • A monitoring well from which a sample is to be collected has been appropriately purged immediately prior to sampling
  • The well purging referred to above is documented by recording:
    • the date of the purging,
    • the time the purging started and stopped, and
    • the volume of fluid removed from the well during purging,
    • a rationale for concluding the purging was complete is recorded,
    • a description of the measures taken to minimize cross-contamination between wells when using non-dedicated equipment.
  • Precautions are taken to minimize the potential for cross-contamination or contamination through preferential pathways.

Records of Site Condition Regulation: There are other methods allowed for taking groundwater samples that do not involve monitoring wells. For example, samples can be collected from an equivalent professionally acceptable groundwater collection method as prescribed by O. Reg 153/04.

Records of Site Condition Regulation: There are additional obligations when creating a QA/QC program and when sampling groundwater. Please refer to O. Reg. 153/04 for the RSC requirements.

Groundwater Sampling

The purpose of groundwater sampling and monitoring programs is to obtain accurate samples and measurements that are representative of the groundwater or aquifer in a study area. Inconsistent and biased samples and measurements lead to incorrect interpretation and wrong remedial actions.

The overall objective of most groundwater sampling programs is to collect samples that are representative of the groundwater conditions at the site. The samples should accurately reflect the physical and chemical properties of the groundwater in the formation interval to be sampled^{footnote 2[2]}. There are three main reasons for collecting representative samples:

• Regulatory compliance monitoring
• Provincial ambient monitoring programs
• Site characterization

Reminder: For information on factors affecting whether or not samples are representative of the groundwater and selection criteria for groundwater purging and sampling devices, see Environmental Characterization and Ground-Water Monitoring: Second Edition^{footnote 3[3]} Chapter 15, and the ASTM references listed in the Resources section of this manual.

The selection of groundwater equipment for sampling or purging a well depends on eleven key factors^{footnote 4[4]}. They are as follows:

1. The sample’s analytical precision and accuracy, which are needed for interpretation
2. The materials used in the construction of the equipment, including cords and holders to fasten the equipment to the well, electrical lines and waterlines (e.g., some equipment can corrode in highly acidic groundwater and bias the sample results)
3. The outer diameter of the equipment to ensure it will fit into the well
4. The lift capacity of the pumping equipment since certain equipment is more suitable for pumping from deeper groundwater zones
5. The controls used to regulate the flow of groundwater through the equipment
6. The simplicity of the equipment for sampling, cleaning and maintenance
7. The durability and life of the equipment
8. The need for portable or dedicated equipment
9. The type of parameters to be analyzed
10. The aquifer properties
11. The cost

Various studies have recommended the following low flow purging and sampling approach when using equipment in test holes to obtain ambient groundwater samples^{footnote 5[5]}:

• The equipment uses a very slow rate of flow during purging and sampling. High speed, high flow pumps and bailers can disturb aquifers and formations resulting in samples with artificially high turbidity compared to the aquifer
• The intake of the equipment (pump) is within the well screen, when present
• The stagnant water column above the well screen is not significantly disturbed
• Water quality indicator parameters such as temperature, conductivity, pH and dissolved oxygen are monitored during purging to verify ambient groundwater is entering the well
• There is little atmospheric contact with the samples
• Samples to be analyzed for heavy metals should be collected with and without the use of filtering devices.

Groundwater monitoring equipment can be:

• Portable (non-dedicated)
• Dedicated
• Designated.

A portable device is a piece of equipment that is used to sample groundwater at multiple test holes and may be used at different locations^{footnote 6[6]}. For example, submersible and peristaltic pumps are commonly used as portable devices.

A dedicated device is a piece of equipment that is permanently installed in a test hole and remains submerged during use. For example, a bladder pump is a device suitable for dedicated installation. Another example of equipment that may be dedicated is an inertial lift pump^{footnote 5[5]}.

Dedicated well monitoring differs from portable monitoring primarily by the permanence of the setup. Portable systems require the use of the same equipment from well to well; therefore great care must be exercised to avoid cross-contamination.

A designated device is a piece of equipment that is assigned for use at only one test hole and does not remain submerged during use. For example, a bailer and a passive diffusion bag sampler are devices that are commonly designated.

Reminder: For further information and clarification on types of devices for sampling groundwater see:

• Practical Handbook for Environmental Site Characterization and Ground-Water Monitoring Second Edition^{footnote 7[7]}, Chapter 15, and
• ASTM Standard D6634 – 01(2006). "Standard Guide for the Selection of Purging and Sampling Devices for Ground-Water Monitoring Wells"^{footnote 8[8]}.

Records of Site Condition Regulation: Starting on July 1, 2011, amendments to O. Reg. 153/04 came into force and apply to phase two environmental site assessments (ESAs) conducted in support of records of site conditions (RSCs). For any such RSC submitted on or after this date, the qualified person conducting or supervising the ESA is responsible for developing a sampling and analysis plan that includes a rationale and procedure for groundwater sampling.

Requirement to Clean Equipment Used in a Well

The qualified person must ensure that the sampling and analysis plan includes a quality assurance and quality control program (QA/QC). The QA/QC program must include a requirement that all non-dedicated sampling and monitoring equipment be cleaned following each use.

Records of Site Condition Regulation: There are additional obligations when creating a QA/QC program and when sampling groundwater. Please refer to O. Reg. 153/04 for the RSC requirements.

Table 12-1: Typical Equipment Used for Sampling Groundwater in the Field

Sampling Device	Description	Advantages	Disadvantages
Headspace Sampling Device - Photo Ionization Detector (PID)	Uses UV light to ionize gases or vapours in the well head space Detects the amount of positive ions by measuring the electrical current produced in the sample To test for a specific chemical a UV light must be used that has an energy ≥ the IP of the chemicalfootnote 9[9]	Uses non-destructive sampling (it does not change the composition of the sample) so it can be used in a series with other detectorsfootnote 10[10] Easy to use and does not require any supporting gasesfootnote 10[10]  (this means that a tank of gas is not required for use)	High humidity may cause an inaccurate (low) reading Lamp may become obstructed by particlesfootnote 9[9] A PID does not detect methane
Headspace Sampling Device - Flame Ionization Detector (FID)	Uses combustion to detect the presence of organic compounds in the well head space	Most effective device for detecting organic carbons – able to detect a wider range of organic compounds than PIDs An FID is much less sensitive to humidity	Uses destructive samplingfootnote 10[10] (this means that the composition of the sample is changed by the process of detecting it) Requires the use of a supportive gas (hydrogenfootnote 9[9]) which is not ideal for a portable sampling devicefootnote 9[9] because a tank of gas must be brought into the field
Groundwater Pumping and Sampling Devices - Combustible Gas Indicator (CGI)	Measures the risk of fire and explosion from flammable vapours found in the well head spacefootnote 11[11] Provides a reading of the concentration in parts per million (ppm), percent combustible gas by volume, or percent Lower Explosive Limit (LEL)footnote 11[11]	Can detect low concentrations of combustible gasfootnote 11[11]	Cannot determine between different combustible compounds Temperature affects the reliability of the reading Deviations from normal oxygen levels may affect the response efficiency (see manufacturer’s specifications for the required range of oxygen concentration)footnote 11[11]
Groundwater Pumping and Sampling Devices - Draeger tubes (detector tubes)footnote 12[12]	Glass vials filled with a chemical reagent known to react with a specific compound. A specific volume of air is pumped into the tube and a reaction indicates the presence and concentration of the chemical	Easy to read Does not need to be calibrated Easy to maintain Available for wide rage of chemicals and chemical groups	Refrigeration is required Can have low accuracy
Groundwater Pumping and Sampling Devices - Bailer	Retrieves a grab sample A tube with a lifting bail on the top and one or two check valves on the bottomfootnote 13[13] As it is lowered to the desired depth, water passes through the check valve into the bailer. When it is pulled up the check valve closes and the water is enclosed inside the bailer footnote 13[13]	Does not require a power source to operate Is not limited by depth Can be manufactured from a variety of materials for sampling different parameters Available in a variety of sizes (e.g., to fit in small diameter well) Inexpensive and widely availablefootnote 13[13] Can be used for purging wells	Cannot guarantee that water sample is discreet. May increase the turbidity of samples Water can become aerated when it is poured into a sample bottle from the bailerfootnote 13[13]
Groundwater Pumping and Sampling Devices - Thief Sampler (Kemmerer)	A grab sampling device that is composed of an open tube Plugs or valves on either end are closed when a trigger is activatedfootnote 14[14]	Can be used to sample at any depthfootnote 14[14] Can obtain a more discreet sample than a bailer Can be manufactured from a variety of materials for sampling different parameters Available in a variety of sizes (e.g., to fit in small diameter well)	A separate device is needed for purging the wellfootnote 14[14] May increase the turbidity of samples Water can become aerated when it is poured into a sample bottle from the sampler More expensive than a bailer
Groundwater Pumping and Sampling Devices - Passive Diffusion Sampler (sometimes called a Passive Diffusion Bag Sampler)footnote 15[15]	In situ sampling device for the analysis of volatile organics in groundwater A polyethylene bag filled with water is hung in a monitoring well until equilibrium has been reached between the contaminants in the sampler and in the well water (usually about two weeks) Retrieved from the well and contents are poured into sample bottles and vials for lab testing.	No disruption to the water columnfootnote 16[16] No need to purge the well, therefore no need to dispose of purged water Relatively inexpensive and easy to install	Water can become aerated when it is poured into a sample bottle from the sampler Not effective for high solubility, high vapour pressure organic compounds such as MTBE, methanol or acetone Not effective for semi-volatile organic compounds (e.g., poly aromatic hydrocarbons), trace metals or other inorganics because they will not diffuse across the polyethylene bag Requires a longer sampling time Only applicable if there is no vertical flow in the well water column
Groundwater Pumping and Sampling Devices - HydraSleeve Samplerfootnote 17[17]	A simple, discrete interval, no-purge grab sampler suitable for all contaminants Along, lay-flat, flexible sleeve with a top check valve and a weight attached to the bottom The HydraSleeve goes in empty and stays sealed going down to the user- selected depth. The check valve opens and the HydraSleeve fills and seals during recover	Sample for all contaminants Large volume for a no-purge sampler Inexpensive and disposable Simple to use No purge water Minimal energy consumption Safer than purge methods	Sample volume is limited in small diameter wells.
Groundwater Pumping and Sampling Devices - Snap Samplerfootnote 18[18]	The Snap Sampler is a sampling device that employs a unique double-end-opening bottle. To operate, Snap Samplers are loaded with bottles. "Snap" caps are set into an open position. Then the samplers are deployed downhole with an attachment (trigger line).  The Snap Sampler bottles seal under the water surface by simply pulling the trigger, pushing the electric trigger button, or pressuring up the pneumatic trigger system. The photograph in the left column illustrates two Snap Samplers. Up to six can be set in series for largest sample volume.	Sample for all contaminants Large volume for a no-purge sampler Inexpensive and disposable Simple to use No purge water Minimal energy consumption Safer than purge methods	Requires 50mm (2 inches) well diameter, and water volume is limited. Maximum sample volume in 50mm wells is 125ml × 6, or 750ml, and 350ml × 6, or 2.1L.
Groundwater Pumping and Sampling Devices - Bladder Pumps	A sealed bladder pump is designed for dedicated sampling Other designs that allow for bladder replacement are available for portable uses Composed of a flexible bladder inside a rigid casing and check valves on either end Gas is intermittently forced into the space around the bladder causing it to be squeezed thus forcing the water up through the discharge line to the surfacefootnote 19[19]	Can obtain representative samples from a wide variety of field conditions Can obtain discreet samples Can run dry without damage Can be lowered into sampling points as small as 1.3 cm (½ inches) in diameter No air is introduced to the sample	Check valves and bladders can be damaged by particulate matter Can be difficult to decontaminate between sampling points Health and safety issues with respect to the transportation of compressed gas cylinders
Groundwater Pumping and Sampling Devices - Inertial Lift Pump	A long semi-rigid tube terminated with a check valve is lowered into the well at the desired depth The tube is oscillated up and down forcing water to flow up the tube A pump can be operated manually or mechanicallyfootnote 20[20]	Inexpensive Can be used for sampling and purging Available in a variety of sizes (e.g., to fit in small diameter well) Can be manufactured from a variety of flexible or rigid materials Not susceptible to damage from particulate matter Easily disassembled for repairs in the field Widely available	Due to the repeated up and down motion used when operating an inertial lift pump, water tends to be agitated and aerated in the water column. This may result in turbid samples and altered parameter concentrations Samples are further aerated on discharge into sample bottles Depth of sampling points is limited Long rigid tubing can be awkward to store and move between sampling locations
Groundwater Pumping and Sampling Devices - Peristaltic Pumpfootnote 21[21]	A common type of suction pump used to sample shallow wells Suction is created when the tubing inside the device is squeezed by rollers	Can obtain discreet samples Can ensure that no contamination of the sample occurs Can run dry without damage Can be used in small diameter wells No air is introduced to the sample Tubing can be manufactured from different materials	Suction can result in the loss of dissolved gases and volatile organic compounds (VOCs) from the sample Limited to a depth of about 7.6 m (25ft)
Groundwater Pumping and Sampling Devices - Electric Submersible Centrifugal Pumpfootnote 22[22]	A pump is located in the well and attached a support or drop pipe An electric motor drives impellers through a shaft and seal arrangement The water is pressurized by the action of the impellers and forced to the surface	Good for sampling at depthfootnote 23[23] Can obtain discreet samples Can be used for rapid purging of wells Can obtain representative samples from a wide variety of field conditions for certain parameters	The motor can overheat and can raise the temperature of water and affect the sample [e.g., loss of dissolved gases and volatile organic compounds (VOCs)]footnote 20[20] Impeller speed can bias sample results Cannot be used in very small diameter wells Some models can be damaged by particulate matter Relatively expensive
Groundwater Pumping and Sampling Devices - Double Acting Piston Pump	A type of pneumatic positive displacement pump Uses a drive-gas piston to drive the water into the discharge tube and up to the surface Can be used for portable and dedicated installations, but is best suited for a dedicated installation	Good for sampling at depth Available in several diameters Constructed of inert materials and can provide representative samples for most parameters Works well for low flow purging in high volume wells	Associated equipment can be cumbersome to transport and difficult to disinfect between uses Can be damaged by running dry Piston seals and valves subject to damage in turbid water Pressure changes can bias sample results There are health and safety considerations with respect to the transportation of compressed gas cylinders
Groundwater Pumping and Sampling Devices - Progressing Cavity Pump (also known as Helical Rotor, or Moyno-type pump)	Includes an electrical motor, a rotor and a stator The pump is located on the ground surface and a drop pipe is attached from the pump and extends into the well. There is a check valve at the bottom of the drop pipe The pump and drop pipe are filled with well water The action of the rotor sucks the water upward through the drop pipe and pump	Suitable for VOCs sample collection Good for sampling at depth [up to 55 m (180ft)] Good where large volumes of water do not need to be purged Discharge rate from the pump can be reduced, making sampling easier Relatively easy to transport for portable sampling Ideal for dedicated sampling because the pump is sealed	Motor operation may increase sample temperature and bias some sample results High flow rates may introduce turbidity and bias inorganic sample results Mechanism may seize up if used infrequently May be damaged by pumping sandy or silty water Requires a power source (battery) Not available for diameters < 5.08 cm (2 inches)
Groundwater Pumping and Sampling Devices - Electric Submersible Gear Pumpsfootnote 24[24]	The pump is located in the well and attached to a support or drop pipe Water is allowed to enter the pump An electric motor in the pump drives two meshing gears The water is pressurized by the action of the gears and forced to the surface through the drop pipe	Can be used for dedicated or portable sampling Good for sampling at depth Can obtain discreet samples Can be used for rapid purging of wells Can obtain a representative sample from a wide variety of field conditions for certain parameters Easily decontaminated between uses Replacement and cleaning of gears can be easily done in the field Some models can pump water with a high particulate matter level If used correctly, provides accurate results when sampling for VOCs, trace metals and other inorganic compounds	Motor operation may increase sample temperature and bias some sample results Gear speed can bias some sample results Some models can be damaged by particulate matter Relatively expensive Not available for diameters < 5.08 cm (2 inches)
Groundwater Pumping and Sampling Devices - Gas displacement pump	The pump is installed into the well with a line for gas and a discharge line The bottom of the pump has a check valve where water is allowed to enter the pump A check valve, in the upper portion of the pump near the discharge line, prevents the backflow of water from the discharge line into the pump An inert gas is forced through the gas line into the pump. The process closes the lower check valve, opens the upper check valve and pushes the water up the discharge line to the surface	Generally not damaged by particulate matter Can be used for dedicated or portable sampling Easy to operate and disassemble for maintenance Good for sampling at depth [up to 76 m (250ft)] Can be used in small diameter wells Can obtain discreet samples	Dissolved gases and VOCs can be lost to the gas in the chamber Drive gas may contaminate the sample Check valves can get stuck open Sometimes the gas pressure will have to be increased to compensate for the weight of the water in the column Not suitable for purging wells Expensive

Specialty Groundwater Sampling Equipment

There are various groundwater sampling devices used with direct push and cone penetration testing (CPT) equipment. The devices provide immediate samples for water chemistry in a portion of an overburden aquifer. These devices also reduce the costs associated with well construction, purging issues and the time required to obtain samples. Examples of these devices include:

• Exposed screen samplers
• Sealed screen samplers
• Dual tube samplers
• Direct push, membrane interface probes (MIP) for semi-quantitative data on VOC concentrations in the subsurface

Reminder: If the person uses direct push or CPT methods to construct holes for the purposes of sampling groundwater, measuring water levels or obtaining other information with respect to groundwater or an aquifer, s/he must meet the requirements of the Wells Regulation and the Wells section of the Ontario Water Resources Act.

Reminder: For further information on pumping, sampling and monitoring equipment, please refer to the following resources:

• Tables and graphics found in Chapter 9: Equipment Installation of Water Supply Wells – Requirements and Best Management Practices,
• Construction Dewatering and Groundwater Control, New Methods and Applications: Third Edition,^{footnote 25[25]}
• Practical Handbook for Environmental Site Characterization and Ground-Water Monitoring: Second Edition,^{footnote 26[26]} and
• Groundwater and Wells: Third Edition.^{footnote 27[27]}

Groundwater Level and Other Monitoring Equipment

Accurate groundwater level data from test holes or dewatering wells allow for the determination and interpretation of static water levels, the potentiometric surface, groundwater flow direction and groundwater gradients. Groundwater level monitoring data are also used in combination with different tests (e.g., pumping tests, slug tests, packer tests) to determine aquifer characteristics.

There is a variety of monitoring equipment that can be used to obtain groundwater level data. The method and instruments used to collect and record changes in groundwater levels will vary depending on the purpose of the study and environmental conditions.

Records of Site Condition Regulation: Starting on July 1, 2011, amendments to O. Reg. 153/04 came into force and apply to phase two environmental site assessments (ESAs) conducted in support of records of site conditions (RSCs). For any such RSC submitted on or after this date, a qualified person conducting or supervising a phase two ESA is obligated to have met a number of specific requirements related to the measurement of groundwater levels in wells when determining groundwater direction as part of the phase two ESA. For further information, see O. Reg. 153/04.

Measurement Systems

There are two main equipment categories for the collection and recording of groundwater data:

• Manual measurements
• Continuous measurements.

Manual Measurement Systems

Manual groundwater level measurement systems are portable and used to obtain a snapshot of the groundwater level(s) at a well or site.^{footnote 28[28]} Examples of manual measurement equipment are listed in Table 12-2.

Table 12-2: Typical Devices and Methods used to Measure Groundwater Levels Manually

Measurement Device	Description
Electrical Probes	A probe (also known as a water-level indicator or electrical tape) that consists of an electrical probe (two electrodes that do not complete a circuit) attached to a graduated tape. The probe is lowered into the well, and when it makes contact with water an electrical circuit is completed, triggering a buzzer and/or light. The depth to the water level is read directly off of the tape at the measuring point. It is the most common method, and is easy to operate. It may not work properly when cascading water conditions are present or when oil or other non-conductive materials are on the water surface.
Interface Probe	An interface probe works similarly to a water level indicator, but has the capability to provide accurate measurements of both LNAPL and DNAPL.
Pressure Transducer – Water Level Sensorfootnote 29[29]	A battery operated pressure-sensitive device that senses the amount of water above it by means of a sensor located near the end of the transducer. The sensor measures total pressure (fluid + atmospheric). Some devices measure fluid pressure directly. Some devices are calibrated to atmospheric pressure. Readings from other devices need to be corrected for atmospheric pressure. It can also be used as part of a continuous measurement system (see Table 12-3).
Bubbler Water Level Sensor	This sensor uses air, generated by a piston pump that is forced through a tube and chamber and into the groundwater. The pressure formed in the tube is directly proportional to the height of the water column above the chamber. The water level is determined by the difference between the barometric air pressure and the pressure inside the tube. It can also be used as part of a continuous measurement system (see Table 12-3).
Popper	This device is a metal cylinder with a concave bottom that is attached to a steel tape and lowered to the water surface of the well. A “popping” (or poppysmic) sound can be heard when the bottom of the cylinder is repeatedly dropped onto the water surface. The steel tape is read at this point (when the “popping” is heard).
Acoustic Well Probe	This device measures the length of time it takes for sound waves to travel down to the water level and bounce back to the device at the top of the well The probe uses an audible mid-range (300 Hz) sound wave which may provide better results than an ultrasonic probe because it is easier to detect and filter out noise.
Ultrasonic	This device measures the length of time it takes for sound waves to travel down to the water level and bounce back to the device at the top of the well. The depth to the water level is calculated by converting the travel time to a distance. Changes in temperature and humidity can affect the reading accuracy. This tends to make the reading less accurate as the depth of the well increases. The device is difficult to use when there is equipment in the well or if the hole is out of plumb.
Radar	This device measures the length of time it takes for a pulsed or high frequency wave to travel down to the water level and reflect back to the device at the top of the well. The depth to the water level is calculated by converting the travel time to a distance. It provides a highly accurate reading. Radar is difficult to use when there is equipment in the well or if the hole is out of plumb.
Laser	This device measures the length of time it takes for a high frequency light pulse to travel down to the water level and reflect back to the device at the top of the well. The depth to the water level is calculated by converting the travel time to a distance. Battery-powered lasers are being used on a trial basis to take water level measurements in wells. It provides a highly accurate reading. Laser is difficult to use when there is equipment in the well or if the hole is out of plumb.
Manometer and Pressure Gauge under Flowing Conditions	If a flowing well is under high pressure, a casing extension may not suffice (see note below) to aid in the measurement of the water level in the well. In these cases, a packer with an attached pressure gauge can be installed within the top of the well casing. The gauge provides the artesian head pressure, which can be converted to a water level elevation above the ground surface. Pressure gauge devices should be used with caution as some flowing wells are not properly constructed to contain the flow of water within the well casing.
Wetted Chalk Tapefootnote 30[30]	This device consists of a steel tape with calibrated visual lengths. Carpenter’s chalk is applied to the bottom 1.5 to 3 m (5 – 10ft) of the tape before lowering it into the well. The tape is lowered into the well to the anticipated water level depth in a manner that does not cause water to splash up on the chalked portion of the tape. This method does not work if groundwater is cascading into the well.
Air Linefootnote 31[31]	A straight, rigid, small-diameter tube (air line) that is installed in a well to several metres below the lowest anticipated water level. The airline is of a known length and is connected to a fitting for a pressure gauge and for an air source. All connections are airtight. Using a hand pump or air compressor, air is pumped into the air line and the pressure is monitored. Once stabilized, the air pressure is recorded and used to determine the water level. It can also be used as part of a continuous measurement system (see Table 12-3).
Float footnote 32[32]	This device consists of a float attached to a length of steel tape. The tape slides over a pulley located above the well. A counterweight is attached to the steel tape at the opposite end from the float. The depth to water is read directly from the steel tape at a known measuring point at the top of the casing. Certain types of floats can be used to obtain continuous water level measurements.

Reminder: Some of the devices in Table 12-2 can be used to measure the water level in a flowing well with a casing extension.

Continuous Measurement Systems

Continuous groundwater level measurement systems consist of equipment that provides for the automated collection of data at a set frequency. The automated collection of frequent and repeated groundwater level data is a necessary component of many hydrogeological investigations (e.g., baseline data). As with manual systems, the type of continuous measurement equipment used is dependent upon the specific data requirements. Examples of continuous measurement equipment are listed in the table below.

Table 12-3: Typical Devices and Methods used to Measure and Record Continuous Groundwater Levels

Device	Description
Float Recorder System	This device consists of a chart recorder and float.The chart recorder is a drum of chart paper with a recorder operated by a mechanical timer. The water level is recorded by the repositioning of a pen on the paper. The pen is connected to the float system and records the movement of the float and the counterweight. This system is useful when electrical power is unavailable or other environmental conditions limit the use of more advanced technology. This system may be subject to failure in winter conditions. This system may not be appropriate for use in small diameter wells due to float size or friction of the line on the casing.
Data Loggerfootnote 33[33]	This device contains microprocessors that are connected to a pressure transducer. In most cases the entire device is housed in a single waterproof casing. The microprocessors contain software and hardware, which automatically collect, record and store water level data at set frequencies over a period of time. The data can be retrieved remotely or downloaded directly from the device (see Figure 12-1 below).

Figure 12-1: Satellite Telemetry System^{footnote 34[34]}

Figure 12-1 shows a digital communication system that allows real-time data acquisition between in situ measurements in a well and a computer network system. An example of this type of system is the MOECC Provincial Groundwater Monitoring Network (PGMN) which is used to record and transmit data on ambient groundwater conditions in real-time. Submersible sensors, such as pressure transducers and data loggers (see Table 12-2 and Table 12-3), and other monitoring equipment are used to measure groundwater conditions on a continuous basis.

Figure 12-2: A Provincial Groundwater Monitoring Network (PGMN) Well

Figure 12-2 shows a monitoring well that is a part of the PGMN. It is equipped with an automatic pressure transducer and datalogger, a dedicated water quality sampling pump, a telemetry system and an optional rain gauge. The data are downloaded remotely by the Ministry of the Environment via the telemetry system. In some cases, the system is connected directly to a telephone cable. Equipment in this and other PGMN wells is powered by batteries and solar panels.

Other Field Monitoring Equipment

Obtaining measurements in the field can provide a good first indication of groundwater quality in a well or at a site. On-site field measurements also help to verify ambient groundwater conditions present during purging. It is important that some measurements, such as pH, dissolved oxygen and oxidation reduction potential (ORP), be taken in the field because exposure to atmospheric conditions may affect the laboratory results. Common parameters that can be measured in the field include the following:

• pH
• Oxidation Reduction Potential (ORP),
• dissolved oxygen
• turbidity
• temperature
• conductivity
• total dissolved solids (TDS)

Figure 12-3: A Multi-Parameter Water Quality Meter

Figure 12-3 shows a multi-parameter water quality meter that can measure dissolved oxygen, conductivity, salinity, resistivity, TDS, pH, ORP, ammonium, nitrate, chloride and temperature if the proper probes are installed on the meter.

Inflatable Packer Systems

Inflatable packers can be installed in a well to conduct a packer test. See Chapter 13: Water Level Measurements, Aquifer Testing & Discharge Water Handling, "Hydraulic Conductivity Tests" section for further information on their use.

Figure 12-4: Inflatable Packer Prior to Installing and Inflating in a Well

Figure 12-5: Cross-Section of a Packer Test Set-Up in a Well

The figure is of a cross-sectional view of a well that has been installed through overburden and completed into bedrock. There are three main components to the figure; the well and associated stratigraphy and hydrostratigraphy, the packer equipment installed within the well, and the packer equipment above ground surface.

The well is shown as a casing that extends to just above ground surface, through the overburden, and partially into the fractured bedrock. The remainder of the well consists of an open hole within the bedrock. The water level is shown to be within the bottom half of the overburden unit. A number of fractures are illustrated within the bedrock.

The well is equipped with a single packer packer system. This includes a series of equipment at ground surface, as well as the packer within the well.

At ground surface, the packer is connected to a 2 separate systems: the air supply and the water pump.

A line with an air supply (compressed gas) and a pressure gauge connect to the pneumatic packer installed in the well in the bedrock formation. A water line, consisting of a water pump, a flow meter, a series of valves, pipes, and water gauges, attaches to the packer rods. The packer rod connects to the perforated water pipe located below the pneumatic packer. During a test, the pneumatic packer system in the well is inflated to isolate the section of the well being tested. Only the section below the packer is being tested. The test length is the distance from the bottom of the packer to the bottom of the open hole.

Reminder: This figure is not to scale, is for illustrative purposes for this chapter only and does not necessarily represent full compliance with other requirements found in the Wells Regulation.

Types of Pumps Used in Dewatering Wells

Various types of pumps are used for dewatering projects. Table 12-4 describes the most common types of pumps used for dewatering.

Table 12-4: Common Types of Pumps Used in Dewatering Wells

Pump	Description
Submersible Pump	Consists of a control box with electrical components Has an excellent range in capacity and pressure because it pushes rather than draws water Requires only one drop pipe (waterline) Can pump up to 7,570 L/min (1,665 IGPM) Runs silently Requires little maintenance Is simple to install Can handle large amounts of sediment but limits its efficiency Sharp sand particles in water will cause pump parts to wear
Hydraulic Submersible Pump	Similar to a submersible pump but uses pressurized hydraulic oil to power the pump rather than electricity Hydraulic hoses are attached from the surface to the pump Can pump fluids with high solids content but this limits its efficiency Can pump from 115 to 68,000 L/min (25 to 14,958 IGPM)
Turbine Submersible Pump	Similar to a submersible pump but typically used for dewatering in small diameter wells that are deep Can pump up to 5,678 L/min (1,249 IGPM) Particulate matter can damage the pump There is a 70 to 80% efficiency where the water is relatively sediment free
Turbine Vertical Line Shaft Pumpfootnote 35[35]	Typically used for pumping moderate to high volumes of water in deep wells Can pump up to 37,854 L/min (8,327 IGPM) More expensive than turbine submersible pumps
Suction Lift Pump for a Wellpoint System	Consists of a suction lift system attached to a number of point wells (not shown) The point wells are completed above the ground surface by connecting to a header pipe (or waterline) The header pipe is connected to the suction lift pump Each point pumps a small volume of water but the entire system can pump high volumes of water using the suction lift pump Maximum lift is 7.6m (25ft) Each well point requires continuous prime The well points are subject to cavitation If a well point breaks prime, air in the system may cause the suction lift pump to cavitate

Below Ground Connections to Wells

It is recognized that below ground connections to well casing will not be made in most test holes and dewatering wells; however, any time connections are made to the well casing below ground, the requirements in the following sections apply.

If a trench is excavated and a test hole or dewatering well is constructed after the trench has been excavated, then:

• the original ground surface is considered the floor of the trench;
• the casing height and surface drainage requirements found in the Wells Regulation and Chapter 9: Completing the Test Hole or Dewatering Well Structure apply; and
• The Wells Regulation requirements in this section and in the "Installing Suitable Sealant into a Trench" section do not apply.

Drilled Test Holes and Dewatering Wells

The Wells Regulation: When making below ground connections to the casing of a drilled test hole or dewatering well the person constructing the well must use a well seal or pitless adapter (including pitless units) and make the connection watertight.

Pitless adapters or pitless units allow lateral pipes (i.e., waterlines) outside a drilled well casing to connect to drop pipes (waterlines) inside the well.

Reminder: A drop pipe usually extends from the connection at the pitless adapter to the pump or intake portion of the pumping equipment inside the well.

Pitless Adapters

A pitless adapter is primarily designed to make a watertight sanitary seal in a smooth casing below the frost level through the casing wall. A pitless adapter:

• connects downhole pumping equipment to piping in the trench, and
• allows the downhole pumping equipment to be easily removed while standing at the ground surface.

The size and number of holes through the casing depends on the design of the pitless adapter and pump equipment.

To ensure that the connection is watertight, it is necessary that a person installing a pitless adapter follows the manufacturer’s specifications and ensures that the adapter being installed is appropriate for the environment and the well design (e.g., casing size).

The Wells Regulation: The person constructing the well must not use a cutting torch to make an opening in the casing wall to accommodate a pitless adapter.

A cutting torch creates an opening that is too irregular to be made watertight.

Figure 12-6: Pitless Adapter

Figure 12-7: Pitless Adapter Installed

Sanitary Well Seals

Sanitary well seals are primarily designed to create a watertight seal where the waterlines, air vents and electrical lines extend through the top of the well casing.

A sanitary well seal consist of a neoprene gasket between two steel plates. When the two plates are tightened together, the neoprene gasket expands, which seals waterlines, air vents, electrical lines and the casing.

When installing a sanitary well seal, it is necessary to follow the manufacturer’s specifications to ensure that the connection is watertight and the appropriate seal is installed for the environment and the well design.

Figure 12-8: Sanitary Well Seal

The photograph shows an example of one kind of sanitary well seal. In this case, a blue steel plate is underlain by a black neoprene gasket. The gasket is underlain by another blue steel plate. One waterline can pass through the centre of the well seal. An air vent can be threaded onto the seal on the left side of the well seal. The red plug can be removed on the right side of the well seal to allow for an electrical line or other equipment through the well seal. By tightening the four steel bolts on top of the well seal, the two plates are tightened together expanding the neoprene gasket. The squeezed gasket seals the waterline, electrical line and the casing. The well seal is typically found at the top of the well casing. Other sanitary well seals have two holes for two waterline installations used in jet pumps.

Other Test Holes and Dewatering Wells

The Wells Regulation: When making a below ground connection to a well casing of a well other than a drilled well (e.g., constructed by boring, digging, augering or direct push equipment), the person constructing the well must make the connection watertight with a durable bonding material.

Any bonding material must be durable and adhere to the side of the casing and the waterline. Also, the bonding material must not impair the water quality.

Large diameter corrugated conduits or other pipe used to protect waterlines in trenches should not extend through the well casing. Only properly connected and sealed waterlines and electrical lines should extend through the casing.

It is important to know and follow the manufacturers’ specifications for bonding material and installation of waterlines through the well casing (e.g., fiberglass, galvanized and concrete).

Reminder: Hydraulic cement looks like other cement and it is used to stop water leaks through cracks and faults in concrete. Tape should be used to hold the cement in the connection area while it sets (cures).

Installing Suitable Sealant Into a Trench

It is recognized that this will not apply to most test holes and dewatering wells. However, when below ground connections are made to a casing of a well, the following will apply to any excavation created.

The Wells Regulation: When making a below ground connection to the casing of a well, the person constructing the well must fill any outside excavation with suitable sealant extending from the casing a minimum distance outward of 20cm (8 inches) and extending from the bottom of the excavation to within 20cm (8 inches) of the ground surface.

The person excavating the trench should consider the direction of the trench and the proximity to potential sources of contamination as the trench can act as a preferential pathway for contaminants.

Venting the Well

The purpose of the air vent is to allow the well to breathe, which allows equalizing pressures (i.e., when water is drawn out, air goes in so the column of water remains at atmospheric pressure at all times) and the venting of natural gases.

Venting After New Test Hole and Dewatering Well Construction

The Wells Regulation: When a new dewatering well is constructed, the well must be vented to the outside atmosphere in a manner that will safely disperse all gases. This requirement does not apply to a:

• test hole, or
• dewatering well where the casing will be used to transmit water out of the well (e.g., driven point dewatering system).

Reminder: Venting may be problematic for some test hole or dewatering well applications such as:

• test holes designed to collect both gas and water samples
• dewatering wells that flow.

Venting exemptions allow for such applications.

Reminder: Flowing wells are not exempt from the regulatory requirement for venting unless the casing is used in some form to transmit water out of the well or the well is a test hole. A mechanical or inflatable packer with an air release valve and air vacuum relief valve may be installed to vent the well to allow air into and out of the well during pumping (see Figure 11-8 and Figure 11-9 of Chapter 11: Flowing Test Holes & Dewatering Wells for further information).

Venting During Pump Installation in Drilled Test Holes and Dewatering Wells

The Wells Regulation: Unless exempt, if a pump is installed in a drilled test hole or dewatering well, the person constructing the well must install an air vent on the well and meet the following requirements:

• The air vent must have a minimum inside diameter of:
  • 0.3 cm (0.12 inches) for a well casing that has an inside diameter <12.7 cm (5 inches), or
  • 1.2 cm (0.47 inches) for a well casing that has an inside diameter ≥12.7 cm (5 inches).
• In an area where there is potential for flooding, the air vent must extend above the maximum anticipated flooding level and not less than 40 cm (16 inches) above the ground surface.
• On a drilled well in a new well pit, the air vent must extend a sufficient height above the covering of the well pit.
• The open end of the air vent must be shielded and screened to prevent the entry of foreign materials (e.g., insects) into the well.

Reminder: A vent with a larger inside diameter will reduce the risk of the vent freezing during periods of extreme cold temperatures.

To assist persons who are designing various test holes and dewatering wells, the Wells Regulation provides an exemption to the venting size and other venting requirements of pump installation for a drilled test hole or dewatering well. The vent sizes and other venting requirements of pump installation for a drilled test hole or dewatering well do not apply:

• to an uncased test hole or dewatering well
• to a test hole or dewatering well where the equipment installation is exempt from the Wells Regulation (e.g., measuring the water level in a well using a water level meter) or where the equipment is installed in an exempted well (see Chapter 3: Exemptions: Wells, Activities & Experienced Professionals for further information)
• to a test hole or dewatering well with a flush-mounted watertight commercially manufactured well cover where there is no potential hazard from natural gas or any other gas
• to a test hole or dewatering well with a well pit where there is no potential hazard from natural gas or any other gas. However, an air vent line must be installed on the new drilled well in a new well pit and must extend above the cover of the well pit

Figure 12-9: Vented Well Plug

Figure 12-9 shows an air vent extending through the centre of a locking well plug.

Figure 12-10: Air Vent Extended Through A Well Plug

Figure 12-10 shows a similar design to Figure 12-9 except the air vent does not extend through the centre of the well plug. These vented well plugs can be used for drilled test holes where pumping equipment has been installed. A shut-off valve has been attached to the air vent to allow for vapour extraction and to prevent the entry of surface water and other foreign materials into the test hole.

Figure 12-11: Drilled Well With a Vented Vermin-Proof Cap

Figure 12-12: Vent Location on Underside of Three Vermin-Proof Caps Commonly Used in Ontario

Figure 12-13: Watertight Cap With Extendable Screened Air Vent Located Above the Well Cap

Figure 12-14: Watertight Cap With Snorkel Vent Used to Prevent Flood Water from Entering the Top of a Drilled Well

Wells Encountering Gas

The Wells Regulation: Where a well is constructed and natural gas is encountered, the person constructing the test hole or dewatering well must immediately notify the well purchaser, the owner of the land on which the well is situated and the Director that the condition exists.

If a test hole or dewatering well is producing a natural gas or other gas and the gas is detected, the well owner must do at least one of the following:

• Abandon the well and take the necessary steps to properly plug and seal the well,
• Take the necessary measures to manage the gas in a way that prevents any potential hazards and ensure the measures are functional at all times, or
• Seek the written consent from the Director to allow for the continued use of the well (see Chapter 16: Abandonment: When to Plug & Seal Test Holes & Dewatering Wells).

For example, a waste disposal site where gases are expected will need to be carefully managed, with special precautions and procedures to prevent harm.

Reminder: See the Encountering Gas, Contamination and Water Quality Problems section of Chapter 6: Constructing the Hole, Casing & Covering the Test Hole or Dewatering Well for further information and best management practices dealing with natural gas.

Well Caps and Covers

The purpose of well caps and covers is to prevent the entry of surface water and other foreign material into the well. The following requirements will apply to covering the well unless an exempted activity is being performed.

The Wells Regulation: If a well is constructed by a method other than boring (augering) or digging, the person constructing the well must seal the top of the casing with a commercially manufactured vermin-proof well cap.

For example, wells constructed by drilling, jetting and driving are captured by this well cap requirement.

The Wells Regulation: If a well is constructed by boring and digging, the person constructing the well must cover the top of the casing with a solid, watertight well cover that prevents the entry of surface water and other foreign materials.

Preventing the entry of other materials includes designing the well cover to be of sufficient strength to withstand any known weight that might be applied to the well cover or cap, and the freezing and thawing action that may cause the cover to break.

Reminder: It is important that anyone constructing a well installs the well cover or cap to the design specifications provided by the manufacturer and ensures that the design will work for the environment and the well.

Records of Site Condition Regulation: Starting on July 1, 2011, amendments to O. Reg. 153/04 came into force and apply to phase two environmental site assessments (ESAs) conducted in support of records of site conditions (RSCs). For any such RSC submitted on or after this date, the qualified person conducting or supervising the ESA must ensure that precautions are taken to minimize the potential for cross-contamination or contamination through preferential pathways when sampling of groundwater is being undertaken to demonstrate if the applicable site condition standard for a contaminant has been met or not.

Records of Site Condition Regulation: There are many additional sampling, analysis and other requirements for phase two ESAs. Please refer to O. Reg. 153/04 for the details.

Covering the Test Hole or Dewatering Well

Dug or Bored (Augered)

The person constructing the well must cover the top of the well casing with a solid watertight well cover so that surface water and other foreign materials cannot enter into the well. This includes fastening and securing the cover to reduce the risk of children being able to access the well.

Figure 12-15: Dug Well With a Solid Well Cover

For additional information on covers for dug or bored wells see the "Well Caps and Covers" section in Chapter 9: Equipment Installation of the Water Supply Wells: Requirements and Best Management Practices manual (available on Ontario.ca).

Drilled or Other

The person constructing the well must seal top of a well casing that is not constructed by digging or boring with a commercially manufactured vermin-proof well cap. This includes a properly installed and sealed sanitary well seal and a watertight and airtight well cap for a jetted or driven point well.

Reminder: Waterlines sealed to the top of the casing and to a pump under a vacuum are considered vermin-proof well caps for dewatering systems using shallow point wells.

Figure 12-16: Vermin-Proof Well Cap

Figure 12-17: Vermin-Proof Cap And Conduit

Figure 12-18: Snap on Caps for Monitoring Wells

Figure 12-19: PVC Slip on Cap for Monitoring Wells

Reminder: Care should be taken when using a PVC slip on cap as it may not be watertight under certain circumstances.

Reminder: See Figure 12-9 and Figure 12-10 on page 58 for photographs of locking J-plugs with air vents.

Figure 12-20: Dewatering Well System With Pressure Lines Connected to the Top of the Casings

Figure 12-20 shows an eductor well dewatering system with twin pressure lines connected to the top of the well casings

Flush-Mounted Well Cover

In certain circumstances, a well can be completed with a flush-mounted watertight commercially manufactured well cover.

The Wells Regulation: Where the well is located in an area where vehicle or pedestrian traffic is likely to pass directly over the well, the person constructing the well can complete it with a flush-mounted watertight commercially manufactured well cover that must be:

• sufficient to prevent entry of surface water and other foreign materials into the well, and
• sufficiently strong, durable and properly installed to protect the well from damage, or the cover must be covered with a metal plate that is sufficiently large and sufficiently strong, durable and properly installed to protect the well cover and the well from damage.

Depending on the type of well, the flush-mounted cover must also meet the well cover or well cap requirements for dug, bored, drilled or other wells if it is used to cover or seal the top of the well casing.

Reminder: For an example of a flush-mounted well cover, see Figure 9-4: An Example of a Flush-Mounted Watertight Commercially Manufactured Well Cover in Chapter 9: Completing the Test Hole or Dewatering Well Structure.

Alternative to a Well Cap or Cover

The Wells Regulation: The cover, cap or seal is not required if all of the following criteria are met:

• a floor is constructed around or adjacent to the casing of the well,
• a pump (includes associated equipment such as waterlines) is installed above or adjacent to the well (this scenario would include wells with a vertical turbine pump, hand pump or other type of pump positioned directly over the casing),
• the top of the casing is shielded in a manner sufficient to prevent entry of any material that may impair the quality of the water in the well, and
• the casing of the well is extended to at least 15 cm (6 inches) above the floor that is constructed around or adjacent to the casing of the well.

Reminder: This type of pump arrangement is not likely to be encountered for most test holes or dewatering wells.

Figure 12-21: example of a well not requiring a cover, cap, or seal: vertical turbine pump installed directly over the well

Casing Height and Mounding

The Wells Regulation: Unless exempt, any person installing equipment in a well must ensure that the casing height, mounding and surface drainage meet requirements discussed in Chapter 9: Completing the Test Hole or Dewatering Well Structure.

Permitted Well Pits for Test Holes or Dewatering Wells

In most circumstances, well pits are not allowed to be constructed on new or existing test holes or dewatering wells.

The Wells Regulation: In only two circumstances, however, a person constructing a new test hole or dewatering well may be allowed to finish the well with a well pit. The Wells Regulation provides options for the construction of permitted well pits depending on the location of the well, the type of equipment used to construct the well and the well’s purpose. The two permitted circumstances are:

1. The Wells Regulation permits the construction of a new test hole or dewatering well with a well pit as long as the well is constructed with diamond drilling equipment in connection with mineral exploration.
2. The Wells Regulation permits the construction of a test hole or dewatering well with a new well pit or the addition of a new well pit to an existing test hole or dewatering well if the well is located where vehicle or pedestrian traffic is likely to pass directly over the well and the well is completed with a flush-mounted well cover in accordance with the Wells Regulation.

Along with the information provided in this section, see the "Plainly Stated" section in this chapter for further requirements and information on permitted well pits including flush-mounted well pits (vaults).

A well pit is designed to:

• contain the upper portion of a drilled or driven test hole or dewatering well,
• prevent the upper portion of the well and waterlines from freezing, and
• allow access to the top of the well.

Well pits were the preferred choice of pump installers when installing waterlines out of the top of a drilled well to a building until the widespread use of submersible pumps, pitless adapters and pitless units began.

Flush-mounted well pits (vaults) continue to be the preferred choice for test hole and some dewatering well installations where the area is subject to traffic or where an above-grade casing would be a hazard, nuisance or subject to damage. This type of completion is set into the surface seal before it has cured and is installed around the well casing, which has been cut off below grade and properly capped or covered. The flush-mounted well pit (vault) structure must be durable and is generally constructed with steel, aluminum or a high-strength composite plastic material. Flush-mounted test holes or dewatering wells should not be installed in low-lying areas that are subject to ponding or flooding. Some examples of flush-mounted well pits (vaults) are shown in Figure 12-24 to Figure 12-27.

There are many problems associated with well pits in Ontario, such as:

• surface water can pond around the casing and above the top of drilled wells,
• large openings in the well pit’s walls can allow surface water and foreign materials to enter the pit and possibly, the top of the well, impairing the well water,
• the structure can be unsafe,
• the structure can be subject to frost heave,
• flush-mounted well pits (vaults) may be damaged by snow removal or other vehicles, and
• surface water can enter the well and cause groundwater mounding.

Reminder: A well pit is considered a confined space. There are many serious risks and hazards associated with this type of confined space including electrocution, asphyxiation, physical hazards such as drowning or falling, presence of poisonous gases and explosive gases. Although much smaller, flush-mounted well pits (vaults) can present similar hazards (e.g., gas and physical hazards). All required preventative measures when entering a confined space must be undertaken prior to accessing or entering any well pit. Further requirements are found in Ontario Regulation 632/05 (Confined Spaces) made under the Occupational Health and Safety Act.

Figure 12-22: A Typical Flush-Mounted Well Pit (Vault)

Figure 12-23: Three Different Sizes of Flush-Mounted Well Pits (Vaults)

Well Pit Walls (Or Casing)

The following Wells Regulation requirements apply when a new permitted well pit, including a flush-mounted well pit (vault), is constructed for a test hole or dewatering well.

The person constructing the well must:

• consider the walls of the well pit as "casing" and
• meet the casing requirements found in Chapter 6: Constructing the Hole, Casing & Covering the Test Hole or Dewatering Well and Chapter 9: Completing the Test Hole or Dewatering Well Structure in this manual.

For example, if a permitted well pit is installed for a test hole or dewatering well, the person constructing the well must ensure that the well pit casing is:

• made of new material, unless it is scheduled to be abandoned within 180 days of completion of the structural stage,
• clean and free of contamination, and
• watertight, including any seams.

As another example, if concrete material is used as well pit casing, the person constructing the well must ensure that the:

• casing sections are properly aligned so that the joints are flush and the casing is centred,
• casing is commercially manufactured and fully cured, and
• joints between casing sections are sealed with a mastic sealing material (e.g., butyl rubber material) approved by the NSF International that remains pliable and waterproof.

Surface Drainage for a Well Pit

The following Wells Regulation requirement applies when a new permitted well pit, including a flush-mounted well pit (vault), is constructed for a test hole or dewatering well.

The person constructing the test hole or dewatering well must ensure that surface water drainage is such that water will not collect or pond in the vicinity of, or within, a permitted well pit’s casing.

Flush-mounted well pits (vaults) for test holes or dewatering wells should not be installed in low-lying areas that are subject to ponding or flooding.

Creating And Filling The Well Pit’s Annular Space

Unless exempt, the following Wells Regulation requirements apply when a new permitted well pit, including a flush-mounted well pit (vault), is constructed for a test hole or dewatering well.

The person constructing the well must:

• ensure that the entire new well pit, from the bottom of the well pit to the ground surface, is constructed with a diameter that is at least 7.6 cm (3 inches) greater than the outside diameter of the well pit’s walls (or casing).
• fill any annular space outside the permitted well pit’s casing, from the bottom of the well pit to the ground surface, with suitable sealant.
• use a suitable sealant with the appropriate structural strength to support the weight of persons and vehicles that may move over the area after it is filled.

If the suitable sealant contains cement, the person constructing the well must:

• allow the cement to set according to the manufacturer’s specifications or for 12 hours, whichever is longer; and
• if, after setting, the sealant has settled or subsided, top up the cement to the ground surface.

The Wells Regulation exempts a person constructing a test hole or dewatering well that is scheduled to be abandoned within 180 days of completion of the structural stage from the above annular space sealing requirements for a permitted well pit. The regulatory exemptions regarding test holes and dewatering wells, that are scheduled to be abandoned within 180 days of completion of their structural stage, allow for well technicians, engineers and geoscientists to use their professional expertise to design and install test holes and dewatering wells on a case by case basis.

Records of Site Condition regulation: Starting on July 1, 2011, O. Reg. 153/04 prescribes that the provisions of the Ontario Water Resources Act and of Regulation 903 of the Revised Regulations of Ontario, 1990 (Wells) made under that Act, that would apply to a test hole but for section 1.1, and subsections 13 (2), 14.1 (2), 14.2 (3), 14.3 (2), 14.4 (4) and 14.5 (3) of that regulation, apply to a monitoring well installed for the purpose of,

1. a phase one environmental site assessment; and
2. a phase two environmental site assessment.

Implications for the Qualified Person

The qualified person shall ensure that the phase two ESA is conducted in accordance with the requirements stated above.

Implications for the Annular Space of a Well Pit

With respect to a well pit’s annular space size and filling, the above requirement in O. Reg. 153/04 means that, if a new test hole is constructed, is scheduled to be abandoned not later than 180 days after the completion of its structural stage, and is to be used as a monitoring well in an ESA for a record of site condition, then:

• the annular space size and filling exemptions for a test hole’s well pit stated in this section do not apply, and
• the annular space size and filling requirements for a test hole’s well pit stated in Table 7-1 of Chapter 7: Annular Space & Sealing do apply.

Reminder: The above requirement in O. Reg. 153/04 also affects obligations relating to casing material, well screen material and shallow works for monitoring wells. See Chapter 3: Exemptions: Wells, Activities & Experienced Professionals and Chapter 6: Constructing the Hole, Casing & Covering the Test Hole or Dewatering Well for further information.

Records of Site Condition regulation: Please refer to O. Reg. 153/04 for RSC requirements.

Reminder: To understand the term "monitoring well" as defined in the Records of Site Condition regulation see O. Reg. 153/04 and Chapter 2: Definitions & Clarifications, Table 2-2.

Well Pit Floor

The following Wells Regulation requirement applies when a new permitted well pit, including a flush-mounted well pit (vault) is constructed for a test hole or dewatering well. The person constructing the well must cover the floor of the new well pit with at least a 10 cm (4 inches) thick layer of suitable sealant that when set to a solid state will be capable of supporting the weight of a person.

Well Pit Cover

The following Wells Regulation requirements apply when a new permitted well pit, including a flush-mounted well pit (vault), is constructed for a test hole or dewatering well.

The person constructing the well must cover of the well pit with a solid, watertight cover, sufficient to prevent the entry of surface water and other foreign materials into the well pit.

In the case of a permitted flush-mounted well pit (vault), the person constructing the well must cover the well pit with, a watertight, commercially manufactured cover that is:

• sufficient to prevent the entry of surface water and other foreign materials into the well and
• sufficiently strong, durable and properly installed to protect the well from damage, or covered with a metal plate that is sufficiently large and strong, durable and properly installed to protect the well and well cover from damage.

The following Wells Regulation requirement applies when a new permitted well pit, other than flush-mounted well pit (vault), is constructed for a new test hole or dewatering well that has been constructed with diamond drilling equipment in connection with mineral exploration.

The person constructing the well must fasten and secure the cover of the well pit in a manner that will make it difficult for children to remove it.

The Wells Regulation exempts the person constructing a permitted flush-mounted well pit (vault) for a test hole or dewatering well from the fastening and securing requirements because other requirements have been put in place to protect the well from damage, surface water and other foreign materials.

The purpose of a metal plate, if used as a cover for a flush-mounted well pit (vault), is to bridge the top of the well and transfer any traffic loadings (whether from vehicles, pedestrians or animals) horizontally so that the top of the well or well pit structure is not subjected to the weight of the vehicles or people.

Reminder: New flush-mounted well pits (vaults) are only allowed in areas that are subject to vehicular and pedestrian traffic.

Keeping the Well Pit Dry

The following Wells Regulation requirements apply when a new permitted well pit, other than flush-mounted well pit vault, is constructed for a new test hole or dewatering well that has been constructed with diamond drilling equipment in connection with mineral exploration.

Sump Pump

The person constructing the well must ensure that the new well pit is kept dry by means of a sump pump. This could also mean a sump hole would need to be installed into the floor of the well pit.

Drainage Pipe

If the water table is substantially lower than the floor of a permitted well pit, the person constructing the test hole or dewatering well may ensure that the new well pit is kept dry by means of a drainage pipe that:

• has a one-way valve to allow water to discharge from the pit but prevents surface water and other foreign materials, including insects and animals, from entering the well pit,
• passes through the layer of sealant, and
• allows water to discharge near the perimeter of the well pit.

As indicated in the best management practice titled "Well Pit Floor" in this section, the suitable sealant used to construct the well pit sump hole should be able to withstand the pumping of any water from the well pit.

The Wells Regulation exempts the person constructing a permitted flush-mounted well pit (vault) for a test hole or dewatering well from the sump pump or drainage pipe requirements. The regulatory exemption regarding test holes and dewatering wells with flush-mounted well pits (vaults), allows for well technicians, engineers and geoscientists to use their professional expertise to design and install test holes and dewatering wells on a case by case basis.

Test Hole or Dewatering Well Casing Height Above Well Pit Floor

The following Wells Regulation requirement applies when a permitted well pit, other than flush-mounted well pit vault, is constructed with or added to a test hole or dewatering well that has been constructed with diamond drilling equipment in connection with mineral exploration.

The person constructing the well must extend the top of the test hole or dewatering well casing at least 40 cm (16 inches) above the floor of the new well pit.

The Wells Regulation exempts the person constructing a new permitted flush-mounted well pit (vault) for a test hole or dewatering well from the casing height requirements. The regulatory exemption regarding test holes and dewatering wells with flush-mounted well pits (vaults), allows for well technicians, engineers and geoscientists to use their professional expertise to design and install test holes and dewatering wells on a case by case basis.

Test Hole or Dewatering Well Cover/Seal & Vent in a Well Pit

The following Wells Regulation requirements apply when a new permitted well pit, other than flush-mounted well pit vault, is constructed for a test hole or dewatering well that has been constructed with diamond drilling equipment in connection with mineral exploration.

The person constructing the well must:

• seal the top of the drilled well casing inside the new well pit with a commercially manufactured sanitary well seal and
• provide an air vent line from the commercially manufactured sanitary well seal to above the cover of the new well pit.

The Wells Regulation exempts the person constructing a permitted flush-mounted well pit (vault) for a test hole or dewatering well from the sealing and venting requirements because other requirements have been put in place to protect the well from damage, surface water and other foreign materials.

Reminder: The top of a test hole or dewatering well inside a new well pit, including a new flush-mounted well pit (vault), must be sealed with a commercially manufactured vermin-proof cap or solid watertight well cover. A commercially manufactured sanitary well seal is considered to be a commercially manufactured vermin-proof cap. For further information on covering a well, see the "Covering the Test Hole or Dewatering Well" section on page 61 of this chapter.

Reminder: To meet the above venting requirement in a permitted well pit, the air vent may extend through the side of the well pit casing (see Figure 12-28 in this chapter).

If there is a potential for hazardous gases to build up in a flush-mounted well pit (vault), see the best management practices in the "Venting During Pump Installation in Drilled Test Holes and Dewatering Wells" section on page 56 of this chapter.

The venting requirements for a drilled test hole or dewatering well completed with a well pit, and where a pump is installed in the well, are detailed in the "Venting During Pump Installation in Drilled Test Holes and Dewatering Wells" section on page 56 of this chapter.

Figures of Installed Flush-Mounted Well Pits (Vaults) and Other Well Pits

Figure 12-24 to Figure 12-28 illustrate examples of the installation of flush-mounted well pits (vaults) and other well pits.

Reminder: The figures do not depict every circumstance. The diagrams are for illustrative purposes only, are not to scale and do not necessarily represent full compliance with other requirements found in the Wells Regulation.

Figure 12-24: Flush-Mounted Well Pit (Vault) For A New Well That Is Not Scheduled To Be Abandoned Within 180 Days

The figure is a cross sectional view of a well located within a well pit. The well and pit are installed at a high point, with the ground surface sloped to prevent ponding of water. The well consists of a well casing, suitable sealant, and well cap. The bottom of the well is not shown in the illustration. The water level is shown within the well but near the bottom of the illustration.

The well is located within a flush-mounted well pit (vault) in the ground. The well pit (vault) is approximately twice as wide as the well. The well pit, from the outside in, consists of suitable sealant, followed by the pit’s (vault’s) wall. The top of the pit is covered by a watertight flush-mounted well cover. The floor of the well pit (vault) consists of suitable sealant that is at least ten centimetres (four inches) thick. At ground surface, beside the well cover, is a well tag permanently affixed and implanted in suitable sealant (i.e., concrete). There is an exploded view of the top of the well pit wall.

Exploded View: The exploded view illustrates that the top of the well pit wall is a J or hook shape, with a gasket or O-ring seated inside the J. A watertight flush-mounted well cover sits on the gasket and the inner part of the pit wall.

• The hole diameter must be at least seven point six centimetres (three inches) greater than the diameter of the flush-mounted well pit vault.
• It is important that the gasket/O-ring be clean (including sand free) and greased to ensure a proper seal and to prevent cracking.
• The well cover must be commercially manufactured and sufficiently strong, durable, and well-insulated to prevent damage to the well.
• Cover should be fastened to prevent tampering.
• The suitable sealant beside the flush-mounted well pit wall and above the pit floor must provide appropriate structural strength to support the weight of persons or vehicles that may move over the well.

Reminder: This figure is not to scale, is for illustrative purposes for this chapter only and does not necessarily represent full compliance with other requirements found in the Wells Regulation.

Figure 12-25: Flush-Mounted Well Pit (Vault) With Metal Plate For A New Well That Is Not Scheduled To Be Abandoned Within 180 Days

The figure is a cross sectional view of a well located within a well pit (vault), which is covered by a solid metal plate. The solid metal plate covering the well and pit has been installed at a high point, with the ground surface sloped to either side to prevent ponding of water. The metal plate is about twice as wide as the borehole, and extends over the well pit (vault), sealant, and into the native soil. The edge of the metal plate is set into a concrete form to secure the metal plate in place.

The well is located within the pit in the ground. The bottom of the well is not shown in the illustration. The water level is shown as a horizontal line within the well but near the bottom of the illustration.

The pit (vault) is approximately twice as wide as the well. From the outside in, the well pit (vault) consists of suitable sealant, followed by a flush-mounted well pit (vault) wall. The well pit (vault) is covered by a watertight flush-mounted well cover. The metal plate is located immediately above the well cover. The floor of the pit consists of suitable sealant at least ten centimetres (four inches) thick.

There is an exploded view of the top of the well pit wall.

Exploded View: The exploded view illustrates that the top of the well pit wall is a J or hook shape, with a gasket or O-ring seated inside the J, and the watertight flush-mounted well cover sits on the gasket and the inner part of the pit wall. The metal plate sits on top of the well cover, the outer part of the pit wall, and the sealant outside of the pit.

• The hole diameter must be at least seven point six centimetres (three inches) greater than the diameter of the flush-mounted well pit vault.
• It is important that the gasket/O-ring be clean (including sand free) and greased to ensure a proper seal and to prevent cracking.
• The well cover must be commercially manufactured and sufficiently strong, durable, and well-insulated to prevent damage to the well.
• Cover should be fastened to prevent tampering.
• The suitable sealant beside the flush-mounted well pit wall and above the pit floor must provide appropriate structural strength to support the weight of persons or vehicles that may move over the well.

Reminder: This figure is not to scale, is for illustrative purposes for this chapter only and does not necessarily represent full compliance with other requirements found in the Wells Regulation.

Figure 12-26: stronger flush-mounted well pit (vault) for a new well that is not scheduled to be abandoned within 180 days.

The figure is a cross sectional view of a well located within a well pit (vault), which is covered by watertight flush-mounted well cover. In this case, the well pit is located in an excavation. The excavation is at least 20 cm (8 inches) wider in diameter than the well pit (vault) and extends to a minimum depth of 30 cm (12 inches) below the frost line. The excavation in which the pit rests is filled with a concrete sealant.

The well and pit are installed at a high point, with the ground surface sloped to prevent ponding of water. At ground surface beside the well cover is a well tag permanently affixed and implanted in concrete sealant. There is an exploded view of the top of the well pit wall.

The well consists of a well casing, concrete sealant, and well cap. The bottom of the well is not shown in the illustration. The water level is shown within the well but near the bottom of the illustration.

The well is located within a pit in the ground. This pit, from the outside in, consists of concrete sealant at least ten centimetres (four inches) wide, followed by a flush-mounted well pit (vault) wall. The top of the well pit (vault) is covered by a watertight flush-mounted well cover. The floor of the pit consists of concrete sealant at least ten centimetres (four inches) thick. Exploded View: The exploded view illustrates that the top of the well pit wall is a J or hook shape, with a gasket or O-ring seated inside the J, and the watertight flush-mounted well cover sits on the gasket and the inner part of the pit wall.

Reminder: This diagram shows a well pit design that has increased structural strength and protection from frost heaving^{footnote 38[38]} compared to Figure 12-24 and Figure 12-25.

Reminder: This figure is not to scale, is for illustrative purposes for this chapter only and does not necessarily represent full compliance with other requirements found in the Wells Regulation.

Figure 12-27: Flush-Mounted Well Pit (Vault) With Vent For A New Well That Is Not Scheduled To Be Abandoned Within 180 Days

The figure is a cross sectional view of a well located within a well pit (vault), which is covered by watertight flush-mounted well cover. In this case, the well pit is located in an excavation. The excavation is at least 20 cm (8 inches) wider in diameter than the well pit (vault) and extends to a minimum depth of 30 cm (12 inches) below the frost line. The excavation in which the pit rests is filled with a concrete sealant.

The well and pit are installed at a high point, with the ground surface sloped to prevent ponding of water. At ground surface beside the well cover is a well tag permanently affixed and implanted in concrete sealant. There is an exploded view of the top of the well pit wall.

The well consists of a well casing with gas vent, suitable sealant, and well cap. The gas vent conduit extends from the left side of the casing, located below the well pit and approximately at the bottom of the sealed excavation and extends horizontally beyond the exaction and into the geological formation off the figure. The bottom of the well is not shown in the illustration. The water level is shown within the well but near the bottom of the illustration.

The well is located within a pit in the ground. This pit, from the outside in, consists of suitable sealant at least ten centimetres (four inches) wide, followed by a flush-mounted well pit (vault) wall. The top of the well pit (vault) is covered by a watertight flush-mounted well cover. The floor of the pit consists of suitable sealant at least ten centimetres (four inches) thick.

Exploded View: The exploded view illustrates that the top of the well pit wall is a J or hook shape, with a gasket or O-ring seated inside the J, and the watertight flush-mounted well cover sits on the gasket and the inner part of the pit wall.

• The use of concrete as a suitable sealant is recommended as a best management practice in this case.
• Vent for gas extends to an approved collection system or to a place where gas can safety disperse.
• The vent must be designed to prevent the entry of surface water or other foreign material.
• The trench for the vent must be sealed with suitable sealant from:
  • The casing outward a minimum of twenty centimetres (seven point nine inches) of the ground surface; and
  • The bottom of the excavation upward to within twenty centimetres (seven point nine inches) of the ground surface.
• The thickness of concrete beside (except around the vent) and below the flush-mounted well pit (vault) is recommended as a best management practice.
• It is important that the gasket/O-ring be clean (including sand free) and greased to ensure a proper seal and to prevent cracking.
• The well cover must be commercially manufactured and sufficiently strong, durable, and well-insulated to prevent damage to the well.
• The well cover should be fastened to prevent tampering.
• The suitable sealant beside the flush-mounted well pit wall and above the pit floor must provide appropriate structural strength to support the weight of persons or vehicles that may move over the well

Reminder: This diagram shows a well pit design for areas where there is the potential for gas and frost heaving.

Reminder: This figure is not to scale, is for illustrative purposes for this chapter only and does not necessarily represent full compliance with other requirements found in the Wells Regulation.

Figure 12-28: An Example of a Well Pit With Sump Pump and Gravity Drain that is Not Scheduled to be Abandoned Within 180 Days

The figure is a cross-sectional view of a well inside of a concrete well pit. There are two major components to the figure; the well and its components, and the well pit and related components.

The drilled well is located at the bottom right of the well pit and below the frost line. As a minimum, the top forty centimetre portion of the well casing is exposed within the well pit, while the rest of the casing is below the bottom of the well pit. The annular space of the drilled well below the well pit is sealed with a suitable sealant.

The top of the drilled well has a sanitary seal from which two pipes extend vertically; a water pipe and an air vent. Both water pipe and air vent bend ninety degrees to the right, slightly above the well casing, and exit the well pit below the frost line. The water pipe and air vent exit the pit through a watertight connection to the well pit casing with durable bonding material. The water pipe is illustrated as remaining horizontal and extending to a distribution system. The air vent has another ninety degree bend and extends vertically through the well pit casing sealant to above ground surface. The top of the air is screened and shielded.

The well pit consists of two concrete tiles with a concrete base with a minimum thickness of ten centimetres (four inches) and a solid, watertight and child proof well pit cover. The lower concrete tile is shown completely below ground surface. The upper concrete tile is on top of the lower tile, and it is noted that the joint between the tiles is sealed with mastic sealant strip (e.g., butyl joint non-toxic sealant). About one-third of the upper concrete tile is above ground surface. The ground surface is highest around the well, with ground surface sloping away from the well. It is noted that mounding around the well is to prevent pooling of water around the well. It is further noted that the casing height above ground surface must be at least forty centimetres (sixteen inches). The well pit is constructed in an excavation which is filled with a suitable sealant and is able to withstand the weight of persons, animals, and vehicles.

On the bottom left side of the well pit, there is a water draining device (sump pump) shown. There are two options for drainage, which are detailed in Exploded Views A and B.

Exploded View A illustrates a sump pump at the bottom of the well pit. The sump pump has a discharge line that extends vertically to above ground surface, where the line bends to the left and exits the concrete tile through a watertight connection to the well pit casing. The discharge line is slightly raised above ground surface to provide a sufficient air gap, and has a one-way valve at the end to prevent insects from entering the pit.

Exploded View B illustrates a gravity drain at the bottom of the well pit. The drain has a one way valve inside the well pit. The drain exits the well pit through a watertight connection, with the drain pointing to a point at a lower elevation than the floor of the well pit. There is a note that states “B is an alternative to A when the water table is substantially lower than the floor of the well pit.”

At the bottom of the figure is the following caption: Sometimes the pump and air tank are located within the well pit.

Reminder: Larger diameter well pits are considered confined spaces. Persons working on well pits must only enter them when adequate safety precautions are followed based on Confined Spaces Regulation 632/05 under the Occupational Health and Safety Act are taken.

Reminder: This figure is not to scale, is for illustrative purposes for this chapter only and does not necessarily represent full compliance with other requirements found in the Wells Regulation.