St. Catharines Combined Sewer Overflows at Niagara Region Facilities

Data presented here is updated every three months. The data contains records from
April 01, 2022 to March 31, 2023.

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

CSO Location Date of Overflow Volume (ML) Reason for Overflow
Port Weller Plant
[map it ] 		Mar 25, 2023 0.128 ML Heavy Precipitation
Port Weller Plant
[map it ] 		Mar 17, 2023 2.897 ML Heavy Precipitation
Snow Melt
Port Weller Plant
[map it ] 		Mar 17, 2023 9.318 ML Heavy Precipitation
Snow Melt
Jordan Valley SPS
[map it ] 		Mar 4, 2023 N/A ML Heavy Precipitation
Snow Melt
Port Dalhousie Plant
[map it ] 		Mar 3, 2023 22.036 ML Heavy Precipitation
Port Weller Plant
[map it ] 		Mar 3, 2023 67.674 ML Heavy Precipitation
Snow Melt
Port Weller Plant
[map it ] 		Mar 3, 2023 43399.000 ML Heavy Precipitation
Snow Melt
Port Weller Plant
[map it ] 		Feb 9, 2023 0.714 ML Heavy Precipitation
Port Dalhousie Plant
[map it ] 		Feb 9, 2023 57.341 ML Heavy Precipitation
Port Weller Plant
[map it ] 		Feb 9, 2023 7.737 ML Heavy Precipitation
More

Historical Overflow Data for St. Catharines

202220212020
Total Overflows: 34
Total Volume: 761.968 ML 		Total Overflows: 41
Total Volume: 305.509 ML 		Total Overflows: 31
Total Volume: 231.800 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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