Grimsby Combined Sewer Overflows at Niagara Region Facilities

Data presented here is updated every three months. The data contains records from
July 01, 2025 to June 30, 2026.

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

CSO Location Date of Overflow Volume (ML) Reason for Overflow
Baker Road Plant Jun 14, 2026 7.686 ML Heavy Precipitation
Biggar Lagoon CSO Sewage Pumping Station May 23, 2026 0.147 ML Heavy Precipitation
Baker Road Plant May 23, 2026 14.083 ML Heavy Precipitation
Grimsby Works Yard CSO May 23, 2026 13.222 ML Heavy Precipitation
Old Orchard Sewage Pumping Station May 23, 2026 4.282 ML Heavy Precipitation
Woodsview Sewage Pumping Station May 23, 2026 1.656 ML Heavy Precipitation
Baker Road Plant Apr 25, 2026 1.467 ML Heavy Precipitation
Grimsby Works Yard CSO Apr 25, 2026 2.030 ML Heavy Precipitation
Grimsby Works Yard CSO Mar 11, 2026 3.298 ML Heavy Precipitation
Old Orchard Sewage Pumping Station Mar 11, 2026 0.822 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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