Grimsby Combined Sewer Overflows at Niagara Region Facilities

Data presented here is updated every three months. The data contains records from
March 01, 2025 to February 28, 2026.

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

CSO Location Date of Overflow Volume (ML) Reason for Overflow
Baker Road Plant Dec 28, 2025 3.520 ML Snow Melt
Heavy Precipitation
Old Orchard Sewage Pumping Station Dec 28, 2025 1.550 ML Heavy Precipitation
Woodsview Sewage Pumping Station Dec 28, 2025 0.580 ML Heavy Precipitation
Grimsby Works Yard CSO Dec 28, 2025 10.046 ML Heavy Precipitation
Grimsby Works Yard CSO Oct 30, 2025 2.731 ML Heavy Precipitation
Old Orchard Sewage Pumping Station Jun 18, 2025 1.713 ML Heavy Precipitation
Woodsview Sewage Pumping Station Jun 18, 2025 0.810 ML Heavy Precipitation
Old Orchard Sewage Pumping Station May 22, 2025 0.370 ML Heavy Precipitation
Baker Road Plant May 22, 2025 27.080 ML Heavy Precipitation
Grimsby Works Yard CSO May 22, 2025 4.603 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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