Storm and wastewater collection

Sewer system

Collection sewers gather wastewater from homes, businesses and industries, transporting the waste or ‘grey’ water through a network of sewers, pumping stations and forcemains to main or trunk sewers. The wastewater is sent to then sent to the Robert O. Pickard Environmental Centre for treatment.

Ottawa’s sewer system covers 2,767 square kilometres and extends from West-Carleton to Cumberland. It includes:

  • 2,000 km of sanitary sewers
  • 125 km of combined sewers
  • 40 lift stations
  • About 27,000 maintenance holes
  • More than 150,000 service connections
  • Sewer pipes ranging in size from 20 cm to three metres in diameter

In the rural areas, other methods of collection are used including:

  • Richmond and Carp are connected to the municipal trunk system
  • Munster Hamlet has a lagoon and spray irrigation
  • Elsewhere individual septic systems are used and the sludge from septic tanks is transported to the Pickard Centre for treatment.


Storm sewers carry rainfall and other surface run-off directly to the nearest creek, stream or river, generally without treatment.

Combined sewers carry both wastewater and run-off to the Pickard Centre for treatment. The stormwater system includes:

  • 900 km of municipal drains in rural area
  • 1,500 km of storm sewers
  • Over 100 stormwater management facilities such as ponds
  • 120,000 building connections

Learn more about how stormwater is managed to help reduce pollutants in runoff and prevent flooding.

Most stormwater is not treated before being released into waterways and can contribute to poor water quality in rivers, lakes, wetlands and streams. Help protect the water supply by ensuring runoff does not carry debris or pollutants by:

  • Selecting native and adapted plants species that require less water, fertilizer and pesticides
  • Keep litter, pet wastes, leaves and debris out of street gutters, storm catchbasin and ditches so they are not washed directly into streams, rivers, lakes and wetlands
  • Apply lawn and garden chemicals sparingly and according to directions
  • Dispose of used oil, antifreeze, paints and other household chemicals at a household hazardous waste depot or Take it Back! retailer, not into catchbasins or ditches
  • Do not hose spilled brake fluid, oil, grease or antifreeze into the street
  • Plant ground cover to reduce soil erosion
  • Wash vehicles at a commercial car wash so that cleaning products do not flow directly into the storm sewers or ditches