The Wastewater Systems Effluent Regulations are federal rules under the Fisheries Act establishing minimum treatment standards for wastewater discharged to Canadian waters. These regulations require municipalities to treat sewage to specified levels before release, protecting aquatic environments from harmful substances. The regulations set limits on biochemical oxygen demand, suspended solids, chlorine residual, and un-ionized ammonia. Municipalities discharging to waters frequented by fish must meet these standards, often requiring significant infrastructure investment in treatment plant upgrades. Transition provisions allowed time for communities to achieve compliance, with larger systems facing earlier deadlines. Provincial regulations may impose additional requirements beyond federal minimums. Meeting effluent regulations is a major capital planning consideration for municipal wastewater systems.