Wastewater is the mixture of liquid and solid materials that residents and businesses flush down toilets and empty down sinks and drains every day. This material then travels through the city’s sanitary sewer system to one of four wastewater treatment plants. 

Toronto's Wastewater Treatment Plants are designed to remove solids, chemicals and other undesirable materials in a reliable, cost-effective and environmentally sound way. Our treatment process ensures that the water released to Lake Ontario meets or exceeds all provincial and federal standards.

Environmental Monitoring and Protection