12 billion litres of raw sewage spilled into Winnipeg’s rivers last year; city blames weather

The Assiniboine River in Winnipeg is pictured on April 23, 2025. (CTV News Winnipeg photo)

More than 12 billion litres of raw sewage leaked into Winnipeg’s rivers last year, according to a report from the city that blames weather for the increase.

The total sewage discharge was revealed in a report to the city’s water, waste and environment committee. The report said during heavy snow or rainfalls, Winnipeg’s combined sewer systems are designed to overflow and discharge into the river to protect basements from flooding.

According to the report, there were 1,332 combined sewer overflow events throughout 2024, during which an estimated 12,186 megalitres (more than 12 billion litres) of raw sewage spilled into the Red and Assiniboine Rivers.

This is enough sewage to fill an Olympic-sized swimming pool more than 4,800 times.

It’s more than double the volume of raw sewage spilled the year prior and higher than the 12-year average.

“This increase in events and volume is explained by the increased rainfall and different river levels,” the report said, noting rainfall in 2024 was up 62 per cent over 2023.

“Because 2023 was a significantly drier year, the above-average rainfall and river levels in 2024 resulted in the increased discharge.”

The city noted “some degradation” in river and stream water quality during dry weather compared to results collected in 2014/15. It said water quality improved during wet weather.

The report is set to be discussed at the city committee on Friday. You can read the full report here.