Wastewater Treatment

Key Messages

  • P.E.I. and Saskatchewan score “A” grades with the highest proportion of treated wastewater in Canada.
  • Newfoundland and Labrador and Nova Scotia get “D–” grades for being the worst-ranked among all jurisdictions.
  • Canada as a whole gets a “B” and ranks 9th among the 16 peer countries.

Putting wastewater treatment in context

Untreated wastewater poses a variety of problems to both human and environmental health because of chemical and biological contaminants that it may contain. A variety of treatments are possible, ranging from preliminary treatment (removing large solids), primary treatment (removing smaller, undissolved solids that float to the top or settle on the bottom), secondary treatment (removing residual organic matter and suspended solids), and tertiary treatment (removing remaining dissolved solids and chemicals such as nitrogen and phosphorus).1

Because of the variety of possible treatments, the easiest way to compare water treatment across regions is to compare the proportion of wastewater that is treated before it is returned to the environment. We compare the proportion of a population in each region whose wastewater receives at least primary treatment.

Ensuring that Canada’s wastewater is properly treated helps to minimize contamination of local watersheds. This helps to maintain the environment and ensure that groundwater remains safe to consume.

How do the provinces rank relative to Canada’s international peers?

P.E.I. (92.1) and Saskatchewan (90.4) are the top-ranked provinces, with 90 per cent or more of the population receiving at least primary treatment for their wastewater. Both provinces receive “A” grades and have treatment shares comparable to Australia (92.3 per cent) and Denmark (93.5 per cent) but behind top-ranked peers the Netherlands (98.8) and the U.K. (97.9), both of which provide wastewater treatment (primary or better) to nearly 100 per cent of their population.

Several provinces are middle-of-the-pack performers. Manitoba (88.4), Alberta (87.9), Ontario (87.5), and Quebec all (86.3) receive “B” grades and provide more than 85 per cent of their populations with at least primary wastewater treatment, comparable to the shares in peer countries Sweden (87.9) and Ireland (87.5).

British Columbia (75.9) and New Brunswick (75.3) provide primary wastewater treatment or better to less than 80 per cent of their inhabitants and score “C” grades, along with Austria (79.1), Norway (77.1), and Japan (71.3).

Newfoundland and Labrador (46.8) and Nova Scotia (59.2) are the worst-ranked among all the jurisdictions, so they get “D–” grades. Nova Scotia provides at least primary wastewater treatment to only 59 per cent of its population, while Newfoundland and Labrador provides primary treatment or better to the wastewater of less than 50 per cent of its population, well below the shares in the worst-performing peer countries, the U.S. (63.7) and Belgium (60).

Overall, Canada (84.3) ranks in the middle of the pack, scoring a “B” and placing 9th among the 16 peer countries.

How do the provinces perform relative to each other?

P.E.I. and Saskatchewan are the standout performers, with at least 90 per cent of the population receiving primary treatment or better for wastewater. Manitoba, Alberta, Ontario, and Quebec do fairly well, scoring “B”s and providing at least primary wastewater treatment to more than 80 per cent of their populations. B.C. and New Brunswick both provide wastewater treatment to roughly 75 per cent of their populations, resulting in “C” grades.

Nova Scotia and Newfoundland and Labrador are well behind the other provinces, with less than 60 of their populations receiving wastewater treatment. In Newfoundland and Labrador, only 47 per cent of the population receives at least primary wastewater treatment.

How do the territories fare on wastewater treatment?

Wastewater treatment data for Canada’s territories are available only collectively. Across the three territories, wastewater treatment is extremely poor. Only 33 per cent of the population receives at least primary treatment of their wastewater, well below the share in Newfoundland and Labrador, the lowest-ranking province. The territories get a “D–” grade.

The territories are not included in the overall provincial and international benchmarking calculations because data for each individual territory were not available for several of the indicators included in the overall environment report card. The Conference Board is, however, committed to including the territories in our analysis, and so we provide information on territorial performance when data are available.

Why do Nova Scotia, Newfoundland and Labrador, and the territories perform so poorly?

In general, most “sewered” wastewater in Canada receives at least primary treatment. However, Nova Scotia and the territories have large portions of their populations (one-third and one-quarter, respectively) whose wastewater is not collected via sewer, but instead is collected in a septic system or holding tank. Because the water treatment rates are multiplied by the proportion of the population receiving sewerage (in order to make international comparisons), these regions score poorly by this measure. It should be noted, however, that wastewater collected in septic systems should (ideally) receive primary water treatment if the septic system is designed and functions correctly, so the water treatment rates calculated here may be underestimated for these regions.

Newfoundland and Labrador’s performance, on the other hand, cannot be explained by poor access to sewers. Over 92 per cent of Newfoundland and Labrador’s population receive sewerage, more than any other province except Saskatchewan. This province simply does not provide sufficient treatment for a large proportion of the wastewater collected by sewer.


1   Environment Canada, Municipal Water and Wastewater Survey: Municipal Water Use 2009 Summary Tables (accessed December 9, 2015).