The official website of the City of London300 Dufferin Avenue519-661-CITY (2489)3-1-1 (within London)
yellow fish saying rainwater only


Our Storm Water System

When there is a heavy rain event, storm water runs from lawns, parks and driveways onto the road and ultimately drains down into the catchbasins of the stormwater drainage system. This water is then released directly into the Thames River. Since storm water is not treated, it is up to all London residents to ensure that only clean water goes into the storm sewer.

Did you know?

The City of London storm water drainage system as of 2018 consists of:

  • 1,400 kilometres of storm gravity sewer
  • 18,600 storm access holes
  • 32,000 catchbasins
  • 100 storm water management facilities
  • 500 outfalls


  • Do not pour anything down the drain that you would not want to put directly into a river or stream
  • Household special waste such as checmicals, old paint, grease and oil should be disposed of properly
  • Use eco-friendly cleansers to wash your car
  • Limit the amount of fertilizers you use on your lawn
  • Ensure your vehicle is not leaking any fluids such as oil
  • Dispose of animal wastes properly
  • Use a rain barrel to harvest, re-use and conserve water
  • Increase the ability of your property to catch rain water by providing permeable surfaces, like gravel and vegetation, around your house which allows ground water and local creeks to replenish, while reducing the strain on the stormwater system
  • Use natural weed and pest controls
  • Collect and properly dispose of lawn debris such as grass clippings, leaves, twigs, stones and pet waste
  • Keep the sewer grate clean of debris
  • Wash your car at a car wash where water is recycled or on a grassy patch of your property so that water is absorbed into the soil
  • In general, nothing but rain water should go down the storm drain
  • Sweep your sidewalk and driveway instead of washing it down
  • Get involved in a storm drain marking program such as the Yellow Fish Road program
  • Keep water from running off your property
  • Develop a rain garden in your yard


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