Wastewater is any water used in a home, school or business that leaves through a drain. Regular activities such as flushing toilets, taking showers, doing laundry, washing dishes produce wastewater which must be treated before returning to the environment. Generally, wastewater is collected in large pipes called sewers and treated at plants that reduce contaminants to a level the environment can handle.

York Region wastewater collection and treatment system is divided into two distinct service areas:

• Most wastewater generated in York Region is collected in a large trunk sewer system called York-Durham Sewage System and treated at the Duffin Creek Water Pollution Control Plant in Pickering before discharging into Lake Ontario. This system currently serves Newmarket, Aurora, King City, Richmond Hill, Vaughan, Markham and Stouffville. Since 2006, a small portion of wastewater flows from Vaughan is being treated in Peel Region.

• Wastewater originated in Keswick, Sutton, Holland Landing, Mount Albert, Schomberg, Nobleton and Kleinburg is collected and treated at individual water pollution control plants. Mount Albert, Holland Landing, Schomberg, Nobleton, Sutton and Kleinburg plants discharge into local rivers and Keswick plant discharge into Lake Simcoe.

Today, York Region operates and maintains 7 wastewater treatment plants, 19 pumping stations, 2 wastewater storage tanks and over 270 Km of sewers. As York Region population continues to grow, more facilities will be required to permit the safe discharge of water back into our rivers and lakes.