Should Canada Set New Limits on Chemicals in Tap Water?
Official title: Guidelines for Canadian drinking water quality — Haloacetic acids
Health Canada wants to set new limits on haloacetic acids (HAAs) in drinking water. These chemicals form when chlorine used to disinfect water reacts with organic matter like decaying leaves. The proposed limit is 0.08 mg/L. While these byproducts carry some health risks, the danger from drinking unchlorinated water is far greater.
Why This Matters
Drink tap water? This affects you. HAAs are in most Canadian tap water because we use chlorine to kill harmful bacteria. Some HAAs may increase cancer risk at high levels. The new rules would require water systems to test more often and keep levels low—especially for brominated HAAs, which are more potent.
What Could Change
Water treatment plants would need to monitor six types of HAAs quarterly and report annual averages. If brominated HAA levels hit 10 µg/L, plants must take action to reduce them. Treatment systems may need to adjust chlorine dosing, remove more organic matter before disinfection, or switch to chloramines in some cases.
Key Issues
- Is 0.08 mg/L the right limit for total haloacetic acids in drinking water?
- Should bromochloroacetic acid (BCAA) be added to the list of monitored HAAs?
- Is the 10 µg/L threshold for brominated HAAs appropriate to trigger action?
How to Participate
- Review the proposed guidelines on Health Canada's Environment and workplace health consultations web page.
- Submit your written comments by email to water-consultations-eau@hc-sc.gc.ca by the deadline.