Draft Haloacetic Acids Drinking-Water Guideline

Summary#

Health Canada has published a draft Guidelines for Canadian drinking water quality — Haloacetic acids under the Canadian Environmental Protection Act, 1999. The draft proposes a maximum acceptable concentration for a group of haloacetic acids (called HAA6) and is available for comment from January 9, 2026 to March 13, 2026; written comments are accepted for 60 days after publication (email: water-consultations-eau@hc-sc.gc.ca).

What it does#

• Proposes a maximum acceptable concentration (MAC) of 0.08 mg/L (80 µg/L) for total HAA6 in drinking water. This would be measured as a locational running annual average based on at least quarterly samples taken in the distribution system.
• Adds bromochloroacetic acid (BCAA) to the five haloacetic acids already considered, so the guideline covers six compounds in total (referred to as HAA6).
• Says that if the locational running annual average for BCAA is 10 µg/L or higher, water systems should take steps to reduce formation of brominated HAAs.
• Recommends keeping HAA levels as low as reasonably achievable (ALARA) while making sure disinfection still works.
• Advises water systems to use monitoring and treatment options (for example: removing organic precursors before disinfection, adjusting disinfectant type or dose, and managing distribution system factors like water age and flushing).
• Notes that reliable analytical methods exist to measure these HAAs at concentrations below the proposed MAC.

Who's affected#

• Municipal and regional water utilities and their operators.
• Laboratories that test drinking water for disinfection by‑products.
• Provincial and territorial regulators and public health bodies, including Health Canada as the guideline author.
• People who drink tap water, especially customers of systems that use surface water or have bromide in the source water.
• It is unclear from the notice whether private well owners would be directly covered by these guidelines; they may still want to be aware of HAA risks.

Why it matters#

• If adopted, the guideline would push many water systems to monitor HAA6 more regularly and possibly change treatment or distribution practices. That can mean extra testing and operational costs for utilities.
• The goal is to reduce long‑term health risks (including cancer risks reported for some HAAs) while keeping water disinfection effective. The draft stresses that the health risk from not disinfecting water is much larger than the risk from these by‑products.
• Systems that use warm surface water or sources with bromide are more likely to see higher HAA levels and may need to act sooner.
• This is a draft guideline open for comment, not a final rule or law. Comments can be sent to water-consultations-eau@hc-sc.gc.ca within 60 days of publication.