Municipal Wastewater Effluent Strategy

Municipal wastewater is one of the largest sources of pollution discharged in Canada’s lakes, rivers and oceans. Through the Canada-wide Strategy for the Management of Municipal Wastewater Effluent (the Strategy) governments have developed a consistent approach to managing wastewater across Canada.

Under the Strategy, all wastewater facilities should eventually achieve a minimum of secondary level treatment. Facilities must regularly monitor and report on the quality of the effluent being discharged.

Newfoundland and Labrador, Nunavut and Québec agree with the environmental and public health objectives of the Strategy, but they have not endorsed it.

What is municipal wastewater?

Municipal wastewater consists of sanitary sewage from homes, businesses, industries and institutions as well as the rain and melted snow that drain into sanitary sewers. Municipal wastewater typically contains human and other organic waste, nutrients, pathogens, microorganisms, suspended solids and household and industrial chemicals. Treating wastewater before it is released into lakes and rivers reduces the risks posed to human health and the environment.

National Performance Standards

National Performance Standards are the minimum requirements for effluent quality from all municipal, community and government wastewater facilities that discharge into lakes, rivers and oceans. The National Performance Standards do not apply to sanitary or combined sewer overflows or to facilities located in geographic areas where extreme climatic conditions impede treatment, such as Canada’s Far North.

While all new wastewater facilities are required to meet the National Performance Standards immediately, provisions for staggered deadlines to the end of 2020, 2030 and 2040 were offered to existing facilities. This was put in place to give the necessary time to plan, finance and construct new infrastructure, while ensuring that improvements are made to the highest risk wastewater facilities first. The National Performance Standards form the basis of the federal government’s Wastewater Systems Effluent Regulations.

The National Performance Standards are:

Carbonaceous biochemical oxygen demand (CBOD5)

The National Performance Standard for carbonaceous biochemical oxygen demand is 25 mg/L.

CBOD5 is the amount of dissolved oxygen required by microorganisms to break down organic carbon and inorganic material in a wastewater sample. When wastewater with a high CBOD5 value is returned to a natural water body, it poses a greater risk of depleting oxygen, harming aquatic organisms and disrupting ecological processes.

Total Suspended Solids (TSS)

The National Performance Standard for TSS is 25 mg/L.

Total suspended solids refers to silt, clay, metals, and other organic and inorganic materials that are undissolved in wastewater. Suspended matter not only decreases water clarity, but harmful bacteria, viruses and heavy metals may attach to the particles and spread through waterways.

Total Residual Chlorine (TRC)

The National Performance Standard for TRC is 0.02 mg/L.

Some wastewater treatment facilities use chlorine as a disinfectant. Chlorine is toxic to aquatic organisms so it must be removed from wastewater before it is discharged to lakes, rivers and oceans. Since the implementation of the Strategy, governments have moved away from using chlorine in favour of other more environmentally-friendly methods of disinfection.

Canada-wide Progress

Most wastewater facilities are meeting the National Performance Standards. Federal, provincial, territorial and municipal governments continue to upgrade and improve wastewater treatment facilities so that by the end of 2040, 100% of wastewater treatment facilities should meet the National Performance Standards. Wastewater treatment facilities that currently exceed the National Performance Standards may still comply with regulations if they have been approved for one of the staggered deadlines.



Data for CBOD5 and TSS include wastewater facilities owned by municipalities, communities, provincial and federal governments, and facilities on Indigenous lands. TRC data excludes facilities owned by the federal government or facilities on Indigenous lands.

Only facilities that process over 100 cubic metres per day of influent have been included. Wastewater facilities from Newfoundland and Labrador, Northwest Territories, Nunavut and Québec are not included. Data for CBOD5 and TSS were obtained from the Government of Canada’s Effluent Regulatory Reporting Information System, which contains the data reported under the Wastewater Systems Effluent Regulations. TRC values were obtained directly from provinces and territories and include facilities that meet the National Performance Standard value for chlorine or use different methods of disinfection.

Download Data

Percentage of Wastewater Treatment Facilities Achieving the National Performance Standards in 2017

Investment in Wastewater Infrastructure in Canada

The map shows the total investment in wastewater infrastructure upgrades by federal, provincial, territorial and municipal governments through cost-sharing agreements since 2002, as reported by Infrastructure Canada in April 2019. Funding formulas may vary. Investments include upgrades to pumping stations, sewer systems and wastewater treatment facilities. Upgrades and investments by governments outside of cost-sharing agreements are not included.


Amount invested: over $11 billion
Number of Projects: 3,100

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