Grimsby Combined Sewer Overflows at Niagara Region Facilities

Data presented here is updated every three months. The data contains records from
September 01, 2025 to August 31, 2026.

Volume is measured in megalitres. (1 megalitre = 1 million litres)

CSO Location Date of Overflow Volume (ML) Reason for Overflow
Grimsby Works Yard CSO Aug 23, 2026 0.153 ML Heavy Precipitation
Old Orchard Sewage Pumping Station Aug 22, 2026 0.908 ML Heavy Precipitation
Woodsview Sewage Pumping Station Aug 22, 2026 N/A ML Heavy Precipitation
Baker Road Plant Aug 2, 2026 62.438 ML Heavy Precipitation
Woodsview Sewage Pumping Station Aug 2, 2026 N/A ML Heavy Precipitation
Biggar Lagoon CSO Sewage Pumping Station Aug 2, 2026 5.343 ML Heavy Precipitation
Grimsby Works Yard CSO Aug 2, 2026 23.525 ML Heavy Precipitation
Old Orchard Sewage Pumping Station Aug 2, 2026 8.856 ML Heavy Precipitation
Baker Road Plant Jul 28, 2026 3.728 ML Heavy Precipitation
Biggar Lagoon CSO Sewage Pumping Station Jul 28, 2026 0.541 ML Heavy Precipitation
More Locations

Historical Overflow Data for Grimsby

202520242023
Total Overflows: 18
Total Volume: 124.085 ML 		Total Overflows: 17
Total Volume: 53.153 ML 		Total Overflows: 30
Total Volume: 54.866 ML

Overflows contain mostly Storm Water

While the volume of an overflow may seem large, the amount of untreated sewage present in the overflow is small when compared to the amount of stormwater or snow melt.

Niagara typically treats about 80,000 megalitres of sewage each year.  The vast majority of wastewater discharged into the sewer system receives full treatment and only a small percentage of this sewage overflows. These overflows usually only occur during periods of heavy rain or during seasonal snow melts.

Historical Data

If you require more detailed information about a specific combined sewage overflow, you can contact the water & wastewater division.

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