Environmental Monitoring & Protection

Washing Wisely Outdoors, Information for Residents

The City of Toronto has a Sewers By-law (PDF) which controls the quality and quantity of substances discharged into the sanitary sewer, storm sewer and natural watercourses. Residents can help keep our waterways clean by performing the following:

  • Don’t pour anything down a catch basin as they are designed for rain water and melted snow only.

  • Report suspected spills into the storm sewer by calling 311.
    Note: under certain circumstances, water from private swimming pools may be discharged into the storm sewer. Visit Swimming Pools, Hot Tubs and Spas for more information.

  • When washing your car, don’t let the wastewater enter the storm sewer by reaching a catch basin.

Car washing
The dirt on cars can contain toxic chemicals, heavy metals, oil and grease. When you wash a car in your driveway or on the street that dirty water, along with the soap used, runs into the storm sewers and straight into local waterways contributing to water pollution and affecting Lake Ontario's water quality.

To avoid having dirty water run into the storm sewer system, consider these options for washing your car:

  • Use a commercial car wash facility (automatic or coin). These facilities are required to follow a set of practices determined by the City, including treating wastewater and discharging it into the sanitary sewer system where it will receive further treatment.
  • Find a location where the wastewater won’t flow into the storm sewer. For example, washing cars on a gravel surface or grass allows the wastewater to be absorbed before it reaches the storm sewer.
  • Dispose of the wastewater into the sanitary sewer. By using a pail, washcloth and only a small amount of water, and then wiping the car dry, the wastewater can be contained in the bucket and disposed of into the sanitary sewer through a laundry sink or toilet. From there it will go to a City wastewater treatment plant.


For a brochure on the above information, click here.