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Water and Waste Department

CSO Master Plan

To see if there is any combined sewer overflow activity in your area, visit MyUtilityInfo.


The City of Winnipeg is proceeding with a major infrastructure upgrade program, called the Combined Sewer Overflow (CSO) Master Plan, to manage the effects of combined sewer overflows (CSOs) on our waterways.

The CSO Master Plan includes proposed CSO control solutions, cost estimates, funding scenarios and provides a roadmap for achieving our goal of reducing CSOs in Winnipeg.

The operation of the combined sewer system in Winnipeg is governed by Environment Act Licence No. 3042 (EA No. 3042), issued by the Province of Manitoba (through Environment and Climate Change, formerly known as Manitoba Sustainable Development or MSD) in September of 2013.

Goals for Reducing CSOs

The CSO Master Plan outlines long-term goals for reducing the amount of CSOs entering our waterways and will be carried out in two phases.

Control Target 1

The CSO Master Plan will work to reduce the effects of CSOs on our waterways by increasing the amount of combined sewer flow that is treated at our sewage treatment plants before being released into the river. The plan is designed to take the 2013 baseline sewer system from collecting about 74 percent of the combined sewer flows and treating it, to collecting and treating 85 percent by 2045.

Control Target 2

The CSO Master Plan may work towards a higher level of CSO capture which is yet to be determined. A percent capture assessment to determine the next level of control is required by the Province on or before April, 2025.

An update on the CSO Master Plan is required to be submitted to Environment and Climate Change by April, 2030.

Note: all goals for CSO reduction are based on the Representative Year.


Last update: March 4, 2025

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