Draft guideline: Haloacetic acids in drinking water

Summary#

Health Canada is asking for feedback on the draft Guidelines for Canadian drinking water quality — Haloacetic acids. The draft is online from January 9, 2026 to March 13, 2026, and written comments are invited within 60 days.

What it does#

• Proposes a maximum acceptable concentration (MAC) of 0.08 mg/L (80 µg/L) for total HAA6 in drinking water.
• Says the MAC would be measured as a locational running annual average from at least quarterly samples in the distribution system.
• Recommends action if bromochloroacetic acid (BCAA) reaches 10 µg/L or higher at a location.
• Urges water systems to keep HAA levels as low as reasonably achievable (ALARA) but not to weaken disinfection.
• Describes monitoring, lab methods, and treatment or distribution options (for example: removing organic precursors, changing disinfectant type or dose, switching to chloramines, reducing water age, or flushing).
• Invites written comments to Health Canada by email during the consultation period.

Who's affected#

• Municipal and other drinking water utilities that treat and distribute disinfected water.
• Provincial and territorial regulators and public health units that use Health Canada guidelines.
• Laboratories that test for haloacetic acids and water system operators who monitor distribution systems.
• Communities that use surface water or sources with higher organic matter or bromide, where HAA levels tend to be higher.
• If unclear: the guideline is a federal health recommendation, not a law; how it would be enforced or adopted provincially is not specified in the notice.

Why it matters#

• Haloacetic acids are disinfection by-products formed when chlorine reacts with natural organic matter. They are linked to health concerns, including cancer risk at low concentrations, so a guideline could change monitoring and treatment priorities.
• Setting a numeric target (0.08 mg/L) and flagging BCAA ≥ 10 µg/L gives operators specific limits to watch for.
• The guideline balances reducing by-products with keeping water effectively disinfected; it warns that disinfection must not be compromised.
• In practice, some water systems may need to adjust treatment processes, increase testing, or improve distribution management to meet the proposed guideline.