The Manitoba government has laid charges under the Environment Act over a release of partially-treated sewage over a seven-week period last year.
The province says a malfunction at the city's south-end treatment plant allowed partially treated sewage to enter the Red River between October and November, 2011.
The province also alleges the city failed to properly monitor the sewage, which delayed the response time.
In written response, the city says it has already taken steps to improve the plant, such as performing more monitoring and a new response protocol when problems arise.
The province recently ordered the city to replace the southend plant with a more modern facility.