Technical bulletin: Adverse drinking water test results — reporting requirements and exemptions
Information for owners and operators of drinking water systems about reporting adverse test results.
Overview
This bulletin outlines information and rules to report adverse drinking water test results for:
- owners and operating authorities of municipal drinking water systems
- non-municipal drinking water systems
- licensed laboratories
Adverse reporting is required under section 18 of the Safe Drinking Water Act, 2002 (SDWA) and Schedule 16 of the Drinking Water Systems regulation: Ontario Regulation 170/03: Drinking Water Systems. This bulletin also outlines some exemptions from the duty to report.
This information is intended to be used as general guidance and may not be applicable to all systems. It is not intended to summarize reporting requirements or exemptions under the Health Protection and Promotion Act or the Ontario Regulation 319/08: Small Drinking Water Systems.
Source law
- Safe Drinking Water Act, 2002
- Ontario Regulation 169/03: Ontario Drinking Water Quality Standards
- Ontario Regulation 170/03: Drinking Water Systems
- Ontario Regulation 248/03: Drinking Water Testing Services
Definitions
- Adverse drinking water test result
- A result that is prescribed as an adverse test result in Schedule 16-3 to Ontario Regulation 170/03 , including an exceedance of an Ontario drinking water quality standard
- Distribution sample
- A sample that is taken from a point that is significantly beyond where the drinking water enters the distribution system or plumbing
- Drinking water
- Water intended for human consumption, or that is required by an act, regulation, order, municipal by-law or other document issued under the authority of an act to be safe to drink (potable) and to not exceed the Ontario drinking water quality standards
- Drinking water test
- Includes a test for the purposes of the Safe Drinking Water Act to assist in the determination of the quality of any waters in respect of a drinking water system
Note: “waters” includes drinking water, raw water, raw water supply and water contained in plumbing.
Prescribed
- Means prescribed by the regulations made under this Act
Treated water sample
- Means a sample from drinking water which has undergone one or more treatment processes and is ready to be distributed to users of the system
Reporting adverse test results
Drinking water system operators routinely collect samples to check water quality and submit them to a licensed laboratory for analysis. If the result is adverse, the laboratory must report the adverse test result to the:
- owner and operator of the drinking water system
- the ministry
- local medical officer of health
The system owner or operator must:
- report the adverse result to the ministry and the local medical officer of health
- take corrective action to resolve the incident
This duplicative reporting helps to ensure all necessary parties are aware of the adverse test result. Ministry water compliance officers will follow up with the system owner and operators to confirm they have taken all required corrective actions in relation to adverse water quality incidents.
Accurate information on chain of custody forms
Licensed laboratories provide instructions on sample collection and submission for persons conducting sampling. When a sample is submitted it must include a chain of custody form (also known as a laboratory submission form or sample requisition form). When accepting samples for analysis, laboratories are required to confirm that all necessary information is recorded on the chain of custody form so that the sample will be routed, analyzed and reported properly.
It is important that complete and accurate information is provided on the chain of custody form so that the laboratory can properly analyze the sample and report the results as required, including any adverse notifications.
The submitter must correctly:
- record the regulation the sample was collected under
- record the sample type (for example, raw, treated, distribution, plumbing)
- identify and fully document reporting exemptions, if applicable
The information on the chain of custody form must not contain any contradictory information. The ministry’s drinking water testing requirements for laboratories website provides information on the minimum requirements for chain of custody forms and best practices.
Laboratories have specific reporting requirements for drinking water samples taken from drinking water systems regulated under the SDWA. In most situations, regulatory reporting requirements are clear. However, this bulletin outlines certain circumstances when a duty to report may not be straightforward.
Where a chain of custody form indicates the results of a sample of drinking water should not be reported under section 18 of the SDWA, the applicable reporting exemption must be identified to the laboratory. Laboratories have been instructed to treat all drinking water samples as reportable unless the submitter has provided the basis for the exemption from reporting in writing. Solely indicating “not reportable” on the chain of custody form with no further explanation is not sufficient documentation for this purpose. Laboratories should review chain of custody forms and request missing information. Potential confusion and reporting errors can be reduced with clear and consistent communication between system owners and operators, samplers, laboratories and provincial officers.
Refer to the Table 3: Scenarios where reporting is not required under Section 18 of the SDWA for examples.
Records
Testing records must be kept in accordance with section 13 of Ontario Regulation 170/03 and section 13 of Ontario Regulation 248/03. Documentation pertaining to why any samples are exempt from reporting must be included in the records retained by the drinking water system owner and licensed laboratory and should be clearly identified on the chain of custody.
Reporting adverse test results
There is a duty to report every prescribed adverse result of a drinking water test conducted on any waters from a regulated municipal drinking water system or a non-municipal drinking water system immediately after the adverse result is obtained. Refer to section 18 of the SDWA and section 16-3 of Schedule 16 to Ontario Regulation 170/03 for more information. Subject to certain exemptions discussed in the reporting exemptions section, the duty to report adverse test results applies in the following circumstances:
- where the drinking water test is required by Ontario Regulation 170/03, an approval, municipal drinking water licence or order, including an Ontario Water Resources Act, R.S.O. 1990 order
- where the drinking water test is conducted by or under the direction of the owner of a drinking water system, the operating authority for a drinking water system or a certified operator or trained person employed by the owner or operating authority
- where the drinking water test is conducted under the direction of a provincial officer, medical officer of health, member of the staff of the medical officer of health, person employed by the Ministry of Health or Ministry of Labour
- where the drinking water test is conducted by continuous monitoring equipment or microbiological in-line testing equipment
- where raw water supplied is intended for human consumption (such as where the owner is claiming the exemption from the requirement to provide treatment equipment under Schedule 2)
Note: if a system is operating under a treatment exemption, all water from the system is considered water intended for human consumption. Raw water samples from systems with a treatment exemption must be clearly marked on the chain of custody form. The form should specify the exemption details, such as ‘Raw for consumption and reportable under Ontario Regulation 170/03’ or ‘Raw — no treatment and reportable under Ontario Regulation 170.03’. The method for recording this information may vary based on your laboratory’s chain of custody. Please contact your laboratory for direction if it is unclear how to best document this information on the chain of custody form.
Exemptions from reporting
Although all samples of ‘drinking water’ tested for the purposes of the Safe Drinking Water Act, 2002 are regulated, the SDWA and its regulations provide several exemptions from the requirement to report adverse drinking water test results as otherwise mandated under section 18 of the Act. In some situations, water samples are not considered to be “drinking water samples” and adverse test results are not required to be reported. The following sections discuss some of these situations in more detail.
Ontario Regulation 170/03 exemptions
Section 16-2 to Schedule 16 to Ontario Regulation 170/03 provides several exemptions from the requirement to report adverse test results. Adverse reporting requirements do not apply to:
- a test of water that is supplied exclusively for:
- agricultural operations
- landscaping operations
- industrial or manufacturing operations, including food manufacturing or processing operations
- swimming pool or skating rink maintenance operations
- a drinking water test for chlorine residual that is conducted to comply with corrective action required by paragraph 1 of section 17-4 of Schedule 17 or paragraph 1 of section 18-4 of Schedule 18
- a drinking water test that is conducted on a sample that was taken from plumbing if the test is conducted solely for the purpose of determining the quality of the water in the plumbing (more detail is provided in the exemptions for samples from plumbing section)
Exemptions provided by regulatory relief conditions
The Safe Drinking Water Act, 2002 allows the Director to grant relief from certain regulatory requirements under specific circumstances. Conditions that are less onerous than the defined regulatory requirement may be imposed by an approval issued by the Director under sections 38 and 60 of the SDWA, or an order issued by a Provincial Officer under section 117 of the SDWA. For further information and additional conditions that may apply to regulatory relief approvals, please refer to the Guide for Applying for Fragmentation and Relief from Regulatory Requirements.
Exemptions provided for samples from plumbing
Sampling after a period of flushing
When plumbing is flushed for a period of time, the water in the plumbing is replaced with water from the drinking water distribution system. If a chlorine residual or microbiological sample is taken after a period of flushing, the ministry will infer that that the test is being conducted to assess the quality of water in the drinking water system, not the plumbing.
Any adverse test result with respect to the prescribed chlorine concentrations or microbiological parameters is reportable under section 16-3(1) of Schedule 16 to Ontario Regulation 170/03. The Schedule 16 exemption for drinking water samples taken from plumbing solely to determine the quality of the water in plumbing is not available after a period of flushing.
Despite this, the ministry will accept that prescribed chlorine concentrations or microbiological parameter exceedances are not reportable under subsection 16-3 (1) of Schedule 16 to Ontario Regulations 170/03 when results from concurrent tests taken at adjacent upstream and downstream distribution system sample locations are not adverse. All testing records must be kept as per the regulation.
Homeowners can contact the local medical officer of health to discuss specific circumstances and any results of a plumbing sample exceedance.
Sampling without a period of flushing
Chlorine residual and total coliforms indicator tests
When a chlorine residual or total coliforms (TC) sample is taken without a period of flushing, adverse test results may be attributed to the water within the plumbing itself:
- a low chlorine residual result may represent a problem within plumbing rather than in the distribution system
- an adverse TC indicator test may indicate contamination of the source supply or distribution or microbiological regrowth within the plumbing
Therefore, the ministry accepts that a system operator may wish to determine whether an adverse chlorine residual or TC result represents a problem solely in a consumer’s plumbing. The Schedule 16 exemption for drinking water samples taken from plumbing without a period of flushing applies if testing is solely to determine the quality of the water in plumbing. (For example, a consumer complaint response).
The detection of Escherichia coli (E. coli) indicates recent fecal contamination and is a rare occurrence within the plumbing system itself. An adverse test result for E. coli does not qualify for the Schedule 16 exemption for drinking water samples taken from plumbing solely to determine the quality of the water in plumbing.
Despite this, the ministry will accept that the presence of E. coli in a plumbing sample is not reportable under subsection 16-3 (1) of Schedule 16 to Ontario Regulation 170/03 when results from concurrent tests taken at adjacent upstream and downstream distribution system sample locations are not adverse. All testing records must be kept as per the regulation. The concurrent distribution sample results should be sufficient for the municipality to determine legally required reporting and corrective actions for the system.
Watermain Disinfection Procedure
The ministry’s Watermain Disinfection Procedure outlines procedures for disinfecting watermains as part of an addition, modification, replacement, extension, planned maintenance or emergency repair to a municipal residential drinking water system. Specific reporting requirements are outlined in that document and should be referred to for additional details.
Process analysers
Adverse test results or equipment malfunctions from process analysers may or may not be reportable. More information is available in the Residual chlorine analyzers technical bulletin.
Water not intended for human consumption
Occasionally, owners or operators of regulated drinking water systems take samples of water that is not intended for human consumption or required to be potable (meet the requirements of Ontario Regulation 169/03). These water samples should be identified as non-potable (or not for human consumption) on the chain of custody form (see the accurate information on chain of custody forms section for more details).
For example, during the construction and commissioning of new watermains, microbiological samples must be taken in accordance with ANSI/AWWA Standard C651. Samples taken to verify the effectiveness of disinfection and demonstrate that it is safe to connect the watermain to the system are considered to be samples of drinking water.
However, where adverse results are obtained, water cannot be directed to users until non-adverse results are obtained. Samples taken from isolated or unconnected portionss of watermains are not of water for human consumption and therefore, adverse results are not reportable.
Other examples include raw surface water, which is generally not intended for human consumption, as it is not treated. Where raw water is not intended for human consumption, a result that exceeds a drinking water quality standard does not trigger the duty to report in section 18 of the Safe Drinking Water Act, 2002.
Table 1: Scenarios where reporting is required under section 18 of the SDWA
| Description | Reason reporting is required under section 18 of the SDWA |
|---|---|
| Treated or distribution samples taken for E. coli/TC analysis to meet Schedule 10, 11 or 12 of Ontario Regulation 170/03 | Adverse results are reportable as the sample is required by regulation |
| Municipality takes a lead sample from residential plumbing as part of required sampling under Schedule 15.1 of Ontario Regulation 170/03 | Adverse results are reportable as the sample of drinking water is required by Schedule 15.1 of Ontario Regulation 170/03 |
| Owner decides to test treated water more frequently than required by Schedule 13 of Ontario Regulation 170/03 for pesticides | Adverse results are reportable as the samples were tested by or pursuant to the direction of the owner of a drinking water system (DWS) |
| Sample taken from the distribution system by the owner of a DWS serving children’s camp that is not yet open to children | Adverse results are reportable as the samples were tested by or pursuant to the direction of the owner of the DWS |
| An existing non-municipal system that is in the process of installing treatment submits a sample of raw water for analysis | Adverse results are reportable as the samples were tested by or pursuant to the direction of the owner of the DWS and the water is intended for human consumption |
| A non-municipal year-round residential system is operating with a treatment exemption (Schedule 2-11) and submits a sample of raw water for analysis | Adverse results are reportable as the samples were tested by or pursuant to the direction of the owner of the DWS and the water is intended for human consumption |
Table 2: Scenarios where reporting is required once within a specific time frame for an individual drinking water system
| Description | Reason reporting is not required |
|---|---|
| Operator takes a distribution chlorine residual, and the result is below 0.05 mg/L free chlorine (or 0.25 mg/L combined chlorine) a report was made within the most recent 24 hours in respect to distribution chlorine residual | Adverse results are not reportable because an adverse report for low distribution chlorine was made in the preceding 24 hours |
| Operator takes a grab sample and observes filter effluent turbidity >1.0 NTU and a report was made within the most recent 24 hours in respect to turbidity (at a system required to provide filtration) | Adverse results are not reportable because an adverse report for high turbidity was made in the preceding 24 hours |
| Operator takes a sodium sample that is above 20 mg/L two years after their last reported sodium exceedance | Adverse results are not reportable because an adverse report for sodium was made in the preceding 57 months |
| Operator takes a fluoride sample from a system that does not fluoridate, and the result is above 1.5 mg/L four years after their last reported fluoride exceedance | Adverse results are not reportable because an adverse report for fluoride was made in the preceding 57 months |
| Operator takes a fluoride sample at the end of the fluoridation process and the results that is above 1.5 mg/L and has made a report to SAC within the last 24 hours | Adverse results are not reportable because an adverse report for fluoride was made in the preceding 24 hours |
Table 3: Scenarios where reporting is not required under Section 18 of the SDWA
| Description | Reason for exemption from reporting under section 18 of the SDWA |
|---|---|
| Municipality takes a microbiological sample from residential plumbing during customer service complaint without flushing the plumbing | Adverse results are generally exempted from reporting by paragraph 2 of section 16-2(2) of Schedule 16 (sample taken solely for the purpose of testing water quality in plumbing) |
| Municipality takes a lead sample from residential plumbing during customer service complaint (not to comply with community lead testing required under Schedule 15.1 of Ontario Regulation 170/03) | Adverse results are exempted by paragraph 2 of section 16-2(2) of Schedule 16 (sample taken solely for the purpose of testing water quality in plumbing) and are not reportable |
| Municipality decides to test raw water from their DWS | Adverse results are not reportable as the raw water is not intended for human consumption |
| Private residence well owner decides to test the water within the home, (well is not part of a DWS regulated under SDWA or Ontario Regulation 319/081 | The adverse results are not reportable as this private residential well is not subject to the SDWA or Ontario Regulation 319/08. |
| Residential homeowner connected to municipal system submits samples for testing | Results are not reportable as the samples are not required by regulation or tested by or pursuant to the direction of the owner of a DWS |
| Sample taken after disinfection of a physically unconnected watermain | Adverse results are not reportable as the water is not intended for human consumption |
| Sample taken of a new connected watermain where the water is physically isolated from the rest of the DWS | Adverse results are not reportable, as the water is not intended for human consumption until clear results are achieved (at which point the isolating valves can be opened and the main put into service). |
| Sample taken in a reservoir that is out of service for repairs | Adverse results are not reportable as the water in the reservoir is not intended for human consumption until clear results are achieved |
| An individual not acting on behalf of the drinking water system owner/operator/operating authority submits a sample from a lunchroom tap in a building connected to a municipal system | Results are not reportable as they are not required by regulation or tested by or pursuant to the direction of the owner of a DWS |
| Sample taken from the tank of a truck transporting water (water hauler) | Results are not reportable as the vehicle does not form part of the DWS and the samples are not required under Ontario Regulation 170/03 |
| Operator takes a chlorine residual as part of the required corrective actions to restore chlorine residual due to a previously reported low chlorine residual. The result is below 0.05 mg/L free chlorine (or 0.25 mg/L combined chlorine) | Results are not reportable because Ontario Regulation 170/03 states section 18 of the SDWA does not apply to a chlorine residual test taken to meet the required correction actions (i.e., paragraph 1 of section 17-4 or 18-4). |
For more information
If you have questions or would like more information about drinking water, contact the ministry’s drinking water hotline:
Footnotes
- footnote[1] Back to paragraph Regulation issued under Health Protection and Promotion Act for small drinking water systems