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City of Winnipeg
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Sewer system

Our wastewater collection (sewer) system is made up of:

Combined sewers

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Illustration of operation of combined sewer system Illustration of operation of combined sewer system during normal weather Illustration of operation of combined sewer system during rainfall
  • A system of single pipes that collect both wastewater from homes, businesses and industries as well as surface runoff from rainstorms and snow melt.

  • There are 79 combined sewer outfalls or outlets to the river system.

  • The older, central region of Winnipeg is served by 1,037 km of combined sewer pipes.

  • Prior to 1937, the collected sewage and storm runoff flowed directly into the local river system without being treated.

  • In 1937, an interceptor sewer system was built to carry sewage in the combined sewer system to the North End Treatment Plant.

  • There are 119 kilometers of interceptor sewers in the city that carry sewage to the three treatment plants.

  • Weirs, or small dams, were installed in all combined sewers near the outlet of the pipe to divert sewage to the interceptor sewer system during dry weather conditions.

  • In wet weather conditions, flows are higher because runoff enters the system. A higher flow means the wastewater level in the pipe may become higher than the height of the weir. When this happens, combined sewers overflow to the river system.

  • Combined sewer overflows occur, on average, 22 times during the year at each outfall.

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Separate sewers

Illustration of operation of separate sewer system

  • A system of two pipes where one pipe carries wastewater and the other carries land drainage and surface runoff from rainstorms and snow melt.

  • The role of the separate sewer system is to collect wastewater from homes, businesses and industries and carry it to a water pollution control centre for treatment.

  • Since the 1960s, new property developments in the city have been serviced by a two-pipe system.

  • The sewage or sanitary sewer system has about 1,423 km of dedicated pipes that are completely separate from the land drainage system.

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Land drainage sewers

  • A system of single pipes that carries rainfall and snow melt runoff from urban areas to the river system.
  • There are 1,173 km of land drainage sewers in Winnipeg.

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Sketch of proposed Crane pumping stationLift stations and diversion structures

  • Because of Winnipeg's relatively flat terrain, it is necessary to pump wastewater using lift stations to the interceptor sewers or to the water pollution control centres.
  • The main purpose of a lift station is to raise sewage to a higher level so that it can be moved into a sewer system where it can flow by gravity.
  • There are 74 wastewater pumping stations and 10 gravity-based wastewater diversion facilities located throughout the city.

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Combined and separate sewer areas

  • The combined sewer system services an area of approximately 8,700 hectares or about 31% of the city.
  • The separate wastewater and land drainage sewers services an area of approximately 22,300 hectares or about 70% of the city.

Map of city showing areas serviced by separate and combined sewer systems

Last updated: July 20, 2017