Grimsby Combined Sewer Overflows at Niagara Region Facilities

Data presented here is updated every three months. The data contains records from
June 01, 2024 to May 31, 2025.

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

CSO Location Date of Overflow Volume (ML) Reason for Overflow
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
Baker Road Plant Apr 2, 2025 39.168 ML Heavy Precipitation
Biggar Lagoon CSO Sewage Pumping Station Apr 2, 2025 3.263 ML Heavy Precipitation
Old Orchard Sewage Pumping Station Apr 2, 2025 4.359 ML Heavy Precipitation
Grimsby Works Yard CSO Apr 2, 2025 14.308 ML Heavy Precipitation
Woodsview Sewage Pumping Station Apr 2, 2025 N/A ML Heavy Precipitation
Baker Road Plant Mar 6, 2025 6.115 ML Heavy Precipitation
Biggar Lagoon CSO Sewage Pumping Station Mar 6, 2025 0.064 ML Heavy Precipitation
More Locations

Historical Overflow Data for Grimsby

202420232022
Total Overflows: 17
Total Volume: 53.153 ML 		Total Overflows: 30
Total Volume: 54.866 ML 		Total Overflows: 18
Total Volume: 72.048 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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