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Haloacetic Acids Reporting Requirements Effective January 1, 2020

The Ministry of Environment, Conservation and Park is reminding Municipal Drinking Water System Owners and Operators that the Ontario Drinking Water Standard for Haloacetic Acids (HAAs) comes into effect January 1, 2020. The standard will be 0.08 mg/L (80 µg/L) and is expressed as a running annual average (RAA).

As of January 1, 2017, Schedule 13-6.1 in O.Reg.170/03 requires owners and operating authorities of municipal residential drinking water systems and non-municipal year-round drinking water systems to take samples quarterly and have them tested for HAAs. Samples must be taken from a location that is likely to have an elevated potential for the formation of HAAs. On January 1, 2020, this section will be amended to include directions on how to calculate RAAs.

In accordance with Schedules 16-6 and 16-7 of O. Reg. 170/03, the owner or operating authority is responsible for calculating the RAA and reporting an adverse test result by written notice using the Notice of Adverse Test Results and Issue Resolution form within 7 calendar days of the completion of the quarter that produced the adverse test result for HAAs.

If licensed laboratories do not meet the calculation exemption requirements as outlined in Schedule 16-6(3.2) of O. Reg. 170/03, they are responsible for calculating the RAA and reporting an adverse test result by written notice within 7 calendar days of the completion of the quarter that produced the adverse result for HAAs. To clarify how to calculate RAA, please refer to the Trihalomethane and HAA sampling and reporting requirements technical bulletin.

The ministry would like to clarify the reporting requirements for HAAs effective January 1, 2020. If an owner/operator calculates the RAA for HAAs on or after January 1, 2020 and the result of the calculation exceeds the standard, the result must be reported as an Adverse Water Quality Incident.

If you are aware your system has elevated HAA levels, the ministry recommends you take proactive steps to reduce the amount of HAAs in your system.  Such steps can include:

  1. Reducing the chlorine dose or changing the disinfectant (e.g. to ozone, chlorine dioxide, UV).
  2. Reducing disinfection by-product precursors (organic material) prior to chlorination. This could include enhanced coagulation or enhanced filtration (e.g. adding granulated activated carbon, nanofiltration).
  3. Optimizing the amount of time chlorine is in contact with water to reduce reaction time but still maintain primary disinfection (CT).
  4. Reducing water age in the distribution system (e.g. by managing storage levels or using auto-flushers).

Please consult the ministry’s Approvals and Licensing prior to making any changes to your treatment processes, as these changes may require updates to your Drinking Water Works Permit and/or Municipal Drinking Water Licence.

Questions can be directed to: mdwlp@ontario.ca.

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