Main contaminants of drinking water

Drinking water in Québec is generally of excellent quality. However, despite all measures in place to monitor its quality, drinking water can sometimes be contaminated to varying degrees. In such instances, temporary protective measures are taken, such as issuing boil water or drinking water avoidance advisories.

Most particularly, drinking water can be contaminated by:

• Micro-organisms
  • Escherichia coli (E. coli), fecal coliforms or enterococci
• Chemicals
  • lead
  • trihalomethanes (THMs)

The Regulation respecting the quality of drinking water  establishes standards for drinking water contaminants that present a health risk. This regulation specifies that drinking water distribution system officials ensure the quality of drinking water by complying with current standards. The Ministère de l’Environnement et de la Lutte contre les changements climatiques (MELCC) enforces the application of the Regulation.

If your drinking water comes from a private well, read Well drinking water contamination.