"Proportion of municipal wastewater volume discharged by treatment category, Canada, 2013 to 2023",,,,,, ,,,,,, Year,Volume of municipal wastewater discharged (million of cubic metres),Combined sewer overflow (percentage),No treatment (percentage),Primary treatment (percentage),Secondary treatment (percentage),Tertiary treatment (percentage) 2013,"5,980",2.40,1.90,25.50,45.80,24.40 2014,"6,064",2.90,1.90,25.20,46.10,24.00 2015,"5,716",3.00,1.80,24.90,46.00,24.30 2016,"5,834",2.30,1.80,25.60,46.30,24.00 2017,"6,115",2.90,1.90,25.10,46.50,23.60 2018,"5,950",3.20,1.80,25.30,45.30,24.30 2019,"6,162",2.20,1.80,24.40,47.10,24.50 2020,"5,910",2.00,1.70,24.50,47.00,24.80 2021,"5,478",2.40,1.40,24.00,46.20,26.10 2022,"5,795",2.40,1.40,23.40,47.30,25.50 2023,"6,031",2.20,1.40,23.70,47.20,25.50 ,,,,,, "Note: Percentages may not add up to 100 due to rounding. Combined sewer overflows correspond to the stormwater and wastewater conveyed into a combined sewer that are discharged directly into receiving waters because they exceed the capacity of the sewer system or treatment plant. No data were available for the sewer systems located in the Northwest Territories, Nunavut and north of the 54th parallel in the provinces of Quebec and Newfoundland and Labrador.",,,,,, "Source: Statistics Canada (2025) Table 38-10-0124-01 Wastewater volumes discharged from municipal sewage systems by treatment category (x 1,000,000) (https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=3810012401) and Table 38-10-0100-01 Combined sewer overflow discharge volumes (x 1,000,000) (https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=3810010001).",,,,,, Available on the Environmental indicators website (www.canada.ca/environmental-indicators).,,,,,,