When it rains in Toronto, a lot of it falls on the roof of your house where it flows to the eavestrough, then down the downspouts and directly into the sewer system. During heavy rainfall, in many areas of the city, millions of litres of rainwater mixes with sewage in the sewer system – overloading it and causeing this mixture to flow, untreated, into our rivers and Lake Ontario.
The result: flooded basements, polluted rivers, contaminated lake water and beach closings.
- Sanitary sewers transport wastewater from a drain, toilet, or sink. This sewer flows to treatment plants for treatment before being released into Lake Ontario.
- Storm sewers capture rainwater or snowmelt from roof top, street catchbasins, parking lot . This water flows into nearby watercourses or the lake without treatment.
- In some parts of the Toronto, a single pipe called a Combined sewer, carries both sanitary and storm drainage. During dry weather, combined sewers carry all contents to treatment plants. However, during wet weather, the volume of water may exceed the treatment plant’s capacity and some of the untreated water overflows into the lake.
With the financial support of the City of Toronto, a series of events, workshop, information table and tours took place during the summer and fall of 2005.
You can help!
- One of the easiest things you can do is to disconnect your downspouts from the sewer system. The city will do the disconnection for free and add a splash pad or rain barrel where the downspout enter the ground.
- Dispose of hazardous waste properly (e.g. paints, motor oil, pesticides) at a city Household Hazardous Waste station and avoid getting them into the sewer.
- Wash your car at a reputable car wash where the waste water is capture and treated before releasing into the environment.
- Maintain your car to avoid oil leaks.
- Reduce or eliminate your use of chemical fertilizers and pesticides.
- Stoop and scoop animal wastes.
- Consider putting in porous pavement or driveway where water can percolate into the ground naturally.
- Consider installing green roof. A green roof is an extension of the existing roof, which involves a special root repelling membrane, a drainage system, a lightweight growing medium and plants. A green roof will absorb storm water and reduce off-site flows; absorb carbon dioxide and work against the greenhouse effect; conserve energy for the building below them; and, can be made into beautiful flower gardens or bountiful food gardens for occupant.
Related Resources
Publications by TCEL
- Urban Hydrological Cycle
- Stormwater Pollution
