Drinking water testing requirements for laboratories

Overview

This page provides clarification on how the Ministry of the Environment, Conservation and Parks interprets certain sections of the Safe Drinking Water Act, 2002 (SDWA) and the Health Protection and Promotion Act (HPPA) and their regulations to:

• ensure all licensed laboratories have a common understanding of the requirements
• safeguard drinking water in Ontario

Chain of custody forms

A chain of custody form (also known as a laboratory submission form or sample requisition form) is used by clients of the laboratory to request sample analysis. Under the Drinking Water Testing Services regulation (Ontario Regulation 248/03), the content of the chain of custody form must be approved by the ministry. The ministry requires that the forms meet the following criteria and may assess them at the laboratory during an inspection:

1. They must be traceable as to the origin of the sample.
2. They must contain, at minimum, the following fields:
   • identification of the laboratory, including name, address, telephone number
   • Drinking Water System (DWS) name, number, physical address and contact information
   • identification of the regulation that applies to the sample(s)
   • name and signature of person who collected the sample
   • name and signature of person submitting the samples
   • sample type (raw, treated, distribution, plumbing)
   • sample location name
   • date and time the sample was collected
   • chlorine residual (where applicable)
   • requested parameters (i.e., E. coli, metals)
   • person who received the samples at the laboratory — signature, date, time

3. They must have a unique identifier and version number (example: form 1, version 1).

On occasion, a client may ask a laboratory to accept the use of a chain of custody form that is not generated by the laboratory for the submission of drinking water samples. If the laboratory agrees to use a client-generated chain of custody form, it must:

1. Review and pre-approve the chain of custody form as being fit for the laboratory’s use for drinking water samples.
2. Retain documentation of having done so.

Client-generated chain of custody form(s) may be assessed as part of the inspection process.

Chain of custody forms—best practices

It is crucial that accurate information is provided on the chain of custody form in order to help ensure the laboratory correctly reports test results to the owner, the ministry’s Spills Action Centre (SAC) and the local medical officer of health/public health unit (PHU). The information on the form should be clear and not contain any contradictory information. 

The laboratory client (for example, DWS owner/operator) must identify and document any applicable reporting exemptions for regulated drinking water samples. For example, drinking water samples that are being submitted as non-reportable under section 18 of the SDWA, the applicable reporting exemption must be identified to the laboratory (for example, regulatory relief, Schedule 16-2(2) of the Drinking Water Systems regulation (Ontario Regulation 170/03) exemption, etc.). Solely indicating “not reportable” on the chain of custody with no further explanation is not sufficient documentation for this purpose. Laboratories should treat all samples as reportable unless a clear exemption from reporting as set out in the regulations or in an approval or order has been identified and documented. Laboratories should review the forms and request missing information. Samples of water that are non-potable should be identified as non-potable or not for consumption on the form.

Sample drop-off depots

The ministry considers any location under the direct care and control of the laboratory that is offsite from the laboratory where drinking water samples are deposited, collected, and stored for shipping to the laboratory as a sample drop-off depot.

Laboratories must ensure that drinking water samples that have been collected for the purpose of the SDWA and/or HPPA that are left at sample drop-off depots are:

• traceable to a particular sample drop-off depot
• accompanied by a chain of custody or submission form
• protected against degradation and/or chemical or biological changes
• secured against loss and tampering

Immediate reporting of adverse test results

For the purposes of reporting adverse water quality test results, the term “immediate” means “without delay from any other action and in accordance with an approved procedure”. There must be no undue delay:

• during the analytical processing of a drinking water sample at a licensed laboratory as outlined in Table 1:  Steps to recognize and report adverse test results
• in reporting the adverse test result to the local medical officer of health, the SAC and the associated DWS owner/operator, as required, once an adverse test result is accepted by qualified staff of a licensed laboratory

Laboratories must have a written procedure for authorization of an adverse test result for release and this procedure is reviewed during an inspection to evaluate its acceptability. Where a procedure is not acceptable, the ministry will require the laboratory to take corrective action. 

Laboratory staff analyzing drinking water samples also have requirements tied to immediate reporting of adverse results. They must:

• adhere to documented training requirements and policies for determining/comparing test results against the Ontario Drinking Water Quality Standards (Ontario Regulator 169/03) and/or limits specifically cited in drinking water legislation
• develop, document, and adhere to, laboratory policies/procedures relating to the business processes described in Table 1
• document and adhere to the same immediate adverse test result reporting timeframes for chemical testing as are in place for microbiological testing and include them in laboratory policies and procedures (i.e., there must be no undue delay in the reporting of any adverse test results to the required authorities)

Uncertainty and reporting of adverse test results

Estimation of the analytical uncertainty of a measurement is a requirement of  ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories  and must be available if requested by the client. However, uncertainty does not provide a reason to not report adverse test results. Adverse results must be reported as required without any regard to calculated uncertainty estimations.

Duplicate data

The following guidance is for licensed laboratories that analyze drinking water samples in duplicate:

• ensure that all quality control criteria is properly documented and understood by analysts
• ensure that prescribed criteria are met when analyzing regulated drinking water samples
• ensure that duplicate analyses are not averaged for the purpose of notification and reporting under the SDWA
• follow the reporting requirements outlined in Table 2
• ensure that an Adverse Water Quality Incident is reported to the required authorities if found in either the first or second aliquot of a duplicate drinking water analysis (outlined in Table 2)
• upload the correct result into the Ministry of the Environment, Conservation and Park’s Drinking Water Information System (DWIS) and the Ministry of Health’s Laboratory Results Management Application (LRMA)

Reporting of provisional adverse results

Sample interference/contamination

Where a laboratory reasonably believes that an adverse result may be erroneous due to laboratory sample interference/contamination (but not as a result of QC failure), the laboratory shall:

1. Document all details relating to the possibility of result error on the analyst worksheet, logbook, final reports, etc.
2. Report the adverse result to all required parties, indicating that the result is provisional until further notice due to the possibility of interferences/contamination associated with the result.
3. If the issue is not resolved within 24 hours, a written report is required providing details in writing to all required parties.
4. Immediately take and document steps to investigate the possibility of interferences/contamination, requesting a resample, if necessary.
5. Keep SAC/PHU/DWS client updated on the laboratory’s internal investigation and provide a completion time where warranted.
6. If the result is confirmed as adverse, notify all parties (SAC, PHU and the DWS owner/operator) of the confirmed result and, where applicable, the reason for the error/contamination.
7. If the result is not adverse, instruct SAC to discard the adverse water quality incident.
8. Record all steps taken.

Dilution

Provisional adverse reporting can be used in situations where a dilution and subsequent re-analysis is necessary. This can be used if the following conditions are met:

• all QC criteria has been met with the exception of the result being greater than the calibration range 
• the result is known to be greater than the standard
• the dilution analysis cannot be completed in a timely manner

Provisional adverse reporting must follow reporting rules of all other regulated reporting requirements.

No data overgrown results

Where an observation of “over-crowding/confluent/non-identifiable microbial growth” is detected on a plate relating to analyses under the SDWA, licensed laboratories are required to report the results to the required parties as no data overgrown (NDOG) results. There are 4 different types of NDOGs that can be reported by a laboratory which are detailed in Table 3 below.

When a licensed laboratory observes overgrowth on a drinking water test plate, they will report an NDOG result as follows:

When uploading overgrown qualifiers to DWIS or LRMA, the laboratory will leave the result field blank and use the applicable NDOG qualifier (i.e., NDOGT) in the value qualifier field.

Note: When a client requests a laboratory perform a total coliform background (TCB) analysis and a high number of individual, discrete TCB colonies in excess of the method’s maximum counting limit (X) is obtained, this does not constitute an overgrown result and there is no requirement to report the result as adverse. In these circumstances, the count should be reported to the client and uploaded as > Xcfu/100mL.

Data reporting to the clients

Data reported to the laboratory’s clients from samples collected for analysis in accordance with the SDWA or the HPPA must:

• be produced by properly licensed and accredited analytical methods
• be numerically identical to any data reported to SAC/PHU /MOH/DWS owner/operator and uploaded to DWIS/LRMA
• meet the ministry’s reporting detection limit (RDL) requirements, where applic able
• be expressed in proper and defensible significant figures
• be expressed to two to three significant figures for the expression of chemical data

The ministry expects that the process or system that reports data for the purpose of complying with the requirements of the SDWA is validated with respect to transmission accuracy and content. Analytical results must be reported down to the ministry’s RDL, where no RDL exists, the results must be reported to the licensed method’s method detection limit (MDL).

The ministry requires that laboratories have procedures in place to ensure that data transfer mechanisms and routines, both manual and electronic, are checked for errors.

Schedule 13-5 of Ontario Regulation 170/03 requires an increased frequency of sampling if an analytical result obtained for any of the parameters listed in Schedules 23 or 24 exceeds one half of the Maximum Allowable Concentration (MAC). Due to the limitations of current analytical methods to achieve lower detection limits, the ministry has set the RDL for certain organic parameters, Benzene and Terbufos at 50% or more of the MAC, and at 100% for Benzo[a]pyrene. For these parameters, a licensed laboratory must be able to achieve MDL at least equal to the RDL. A positive result above their MDL would trigger increased frequency of sampling, but a result equal to their MDL would not.

Please contact the Ministry’s Laboratory Licensing and Compliance Program (LLCP) by emailing LLCP@ontario.ca for more details on RDLs.

Data reporting to the ministry

Ontario Regulation 248/03 requires laboratories to report results from drinking water tests in a form approved by the Director. This requirement is currently met when laboratories upload drinking water test results to the DWIS (SDWA) or LRMA (HPPA). Results must be uploaded within 10 days of them being authorized for reporting. If a laboratory is experiencing issues with uploading test results, they must follow the steps outlined below:

For Ontario Regulation 170/03 DWS and Ontario Regulation 243/07 facilities

1. Document all actions taken to upload the information.
2. Verify that the upload failure is caused by a LSN issue by contacting lsb.reg170_lsb@ontario.ca.
3. If the problem is related to a profile issue, contact the Registration Team at: 
   Toll-free: 1-866-793-2588 or email waterforms@ontario.ca.
4. Contact the client to request the submission of the completed or corrected LSN.
5. Attempt to upload again within 20 days of the original failure.
6. If the upload is still unsuccessful after 20 days, contact the Laboratory Licensing and Compliance Program by emailing LLCP@ontario.ca for further follow up.

For Ontario Regulation 319/08 Small DWS

1. Document all actions taken to upload the information
2. Contact the local PHU for a resolution

Testing and reporting of aggregated parameters

In the case where aggregated parameter data are to be reported to DWIS, the ministry requires that the “total” sum of the aggregate be reported, not individual parameters. Laboratories hired to perform the analyses of various aggregated parameters (i.e., Aldrin + Dieldrin, DDT + metabolites, etc.) must be licensed to analyze all parameters of that specific aggregated test. Additionally, the SDWA requires that the “total” analyses must be conducted at one laboratory.

Currently, the accreditation bodies may not accredit calculated parameters, however, the ministry will licence them.

Correcting erroneous data

When a laboratory identifies an error in their data reporting, the laboratory shall:

1. Document all details pertaining to the erroneous data
2. Contact the required parties
   1. If the erroneous result was reported as an adverse water quality Incident, verbally contact SAC, DWS owner/operator and PHU and retract the erroneous result. Provide details about the error and the correct result.
   2. Provide written notification to the required parties indicating the retraction of the erroneous data directly on the ministry’s “Notice of Adverse Test Results and Other Problems and Notice of Issue Resolution at Drinking Water Systems” form. Include the correct result.
3. If the data has already been uploaded to the ministry databases, the lab shall:

Drinking Water Information System (DWIS)

Contact the Help Desk at opssd@ontario.ca or by calling the help desk at Toll-free: 1-888-677-4873. Request the removal of the erroneous data, including the sample submission ID that used to upload all erroneous results. Upload correct results and any other results that were inactivated within the submission ID to DWIS. The Help Desk can also assist for issues such as data correction (delete lab sample submission(s)), upload issues or DWIS technical assistance.

Note: All results uploaded under the submission ID will be inactivated in DWIS.

Note: A new submission ID must be used to upload the results. We encourage labs to use the same submission ID used to upload the original data appended with an A, i.e., original submission ID 123456 will be re-uploaded as submission ID 123456A.

Laboratory result management system application (LRMA)

Log onto LRMA and toggle the "ignore" button to “true”. Upload the correct result under a new sub-mission ID.

If necessary, contact the Public Health Solutions Service Desk at: 
PublicHealthSolutions@ontario.ca 
Toll-free: 1-866-272-2794 
416-327-3512 (in the GTA).

For more information

If you have questions or would like more information about drinking water:

• email the ministry’s Laboratory Licensing and Compliance Program at llcp@ontario.ca
•  visit ontario.ca/drinkingwater