Access to clean water is a key aspect of quality of life and fundamental to human health. Canada has around 7% of the world’s freshwater supply, making it a very water-rich country. However, an abundant supply of fresh water is not the same as an abundant supply of good-quality water.

In this article, we explore the statistics around water quality in Canada, from lakes and rivers to tap water. You will also find a brief guide on how water quality is measured towards the end of the article.

Water Quality Statistics for Canadians

  • Freshwater covers 8.9% of Canada’s total area.
  • Canada’s water quality is the best in the Americas and globally ranks 24th.
  • On average, Canadians use 1,687 gallons of water per capita per day.
  • 83% of global drinking water contains microplastics.
  • Between 2018 and 2020, water samples were excellent at 45% of monitoring sites
  • The Great Lakes contain 18% of the freshwater in the world.
  • Based on phosphorus and nitrogen levels, the St. Lawrence River was rated poor between 2017 and 2019.
  • The level of algae growth in Lake Winnipeg is 500% higher than before Europeans settled in the area.

Water Quality in Canada

The water quality of Canada’s 2 million lakes and 8,500 rivers, which cover 8.9% of the total area of Canada, is ranked the best in the Americas. Globally, according to the Environmental Performance Index, Canada ranks 24th for overall sanitation drinking water, 31st for sanitation, and 22nd for drinking water.

With 7% of the world’s freshwater supply, Canada has the third-largest supply in the world. This can easily lead to thinking that we have an endless supply of water. However, in reality, the supply of accessible clean water is limited.

Use of Freshwater in Canada

In Canada, freshwater is used for municipal purposes such as drinking water, manufacturing, agriculture, the oil and gas industry, mining, and generating thermal power. When the quality of water degrades, it affects human uses of water as well as aquatic life.

For example, if the level of nutrients rises above normal, it can result in excessive plant growth, and reduce the level of dissolved oxygen in the water. High concentrations of nutrients in the water can encourage more algae growth, which can cause health effects in people and animals.

Water Consumption in Canada

Canada has the third highest water consumption rate in the world per capita according to the Water Footprint Calculator. The only countries that consume more water per capita are the United Arab Emirates and the United States. On average, Canadians use 1,687 gallons of water every day. In the United Arab Emirates, the rate is 1,687 gallons, and in the United States 2,200 gallons per day.

In Canada, 35% of water is used for bathing and showering, 30% for flushing the toilet, 25% for doing laundry and cleaning, and 10% for cooking and drinking.

Drinking Water Guidelines in Canada

In Canada, drinking water is generally considered to be of excellent quality. However, water in nature picks up bits of anything it comes into contact with. This includes silt, vegetation, minerals, fertilizers, and run-off from agriculture.

Many of these substances are harmless, but some could pose a health risk. To address this, Health Canada, together with the federal, provincial, and territorial governments, has developed guidelines for drinking water.

The guidelines set the levels for microbiological quality, chemical and radiological quality, and aesthetic quality, such as taste, colour, and odour. Canadian municipalities are responsible for testing the water supply in their jurisdiction to ensure it meets the guidelines for safe drinking water.

Tap Water Contaminants

Despite the efforts to ensure Canadian tap water is always clean and safe to drink, there have been instances when the water has been contaminated. For example, in 2017, the level of atrazine pesticide in the drinking water in Montreal and Toronto was above safe standards.

Microplastics are present in 83% of tap water around the globe. The highest concentrations of microplastics are found in tap water in North America.

Freshwater Quality in Canada

The quality of freshwater in Canada has remained relatively stable. The quality of freshwater in rivers is fair to good. However, the quality is variable across the country, especially near agricultural areas or city centres.

Between 2002 and 2020, the water quality in 60% of monitoring sites on Canada’s rivers has not changed. During the same period, the water quality deteriorated at 30% of the sites and improved only at 10% of the sites. Between 2018 and 2020, the quality of water was excellent at 45% of the monitoring sites, 38% were fair, 14% marginal, and 2% were poor.

Water Quality in the Great Lakes

The Great Lakes, which contain 18% of the world’s freshwater, are a fundamental water source in Canada and the Great Lakes basin supports 9 out of the 20 largest cities in Canada. However, the large population and the industrial, urban, and agricultural development in the area place a great strain on the capacity of the lakes to support healthy ecosystems.

The Great Lakes Water Quality Agreement (GLWQA) between Canada and the United States has identified 43 areas of concern across the Great Lakes. 26 of these areas of concern are on the US side of the lakes, 12 are in Canadian waters, and 5 are in shared waters.

The level of phosphorus in the Great Lakes has been one of the main concerns. Since the 1970s, the level of phosphorus has declined in Huron and Ontario Lakes, in Georgian Bay, and the western and eastern basins of Lake Erie.

Water Quality in the St. Lawrence River

The St. Lawrence River is an important commercial waterway and links the Great Lakes and the Atlantic Ocean. The river together with various lakes and freshwater reaches, its long estuary, and a gulf, form a complex ecosystem. This ecosystem is home to a wide range of animal and plant life.

The level of phosphorus in the river is a concern for water quality. It enters the river through agricultural runoff, air pollution, and municipal and industrial wastewater. Between 2017 and 2019, the phosphorus and nitrogen levels in the river were rated poor because 50% of samples exceeded water quality guidelines.

Water Quality in Lake Simcoe and Georgian Bay

Lake Simcoe is to the north of Toronto and apart from the Great Lakes, it is the largest lake in southern Ontario. It supplies water to eight municipalities in the area. The oxygen levels in Lake Simcoe have dropped because of higher-than-usual levels of phosphorus.

The Georgian Bay includes the United Nations Educational, Scientific, and Cultural Organisation, which is a designated Biosphere Reserve. The Bay’s water quality is under threat from shoreline development, high levels of phosphorus input, and the growth of toxic algae.

Ontario has set a target to reduce the input of phosphorus into Lake Simcoe to 44,000 kg per year by 2045. By March 2015, measures put in place were preventing about 4,040 kg of phosphorus from entering the lake, while projects around the Georgian Bay, stopped 124 kg of phosphorus from reaching the Bay’s waters each year.

Lake Winnipeg

Lake Winnipeg is the sixth-largest freshwater lake in Canada. The levels of phosphorus and nitrogen in Lake Winnipeg have increased following the draining of wetlands, increased agriculture, and growing cities in the area. As a result, the growth of algae in the lake is now around 500% higher compared to before the European settlers arrived.

Projects to reduce phosphorus levels include creating fencing that prevents livestock from entering the lake and rivers connected to it, stabilising lake shorelines and river banks, restoring wetlands, and planting shrubs, plants, and trees that are native to the area. The target is to reduce the input of phosphorus by 50% to the level before 1990. The level of phosphorus was 0.1 mg per litre in 2013 compared to 0.05 mg before 1990.

Marine Pollution

Canada’s coastline is the longest in the world and stretches 243,000 km along the Atlantic, Arctic, and Pacific oceans as well as the Great Lakes. Marine pollution is harmful to ocean ecosystems, creatures, and resources. A key part of controlling marine pollution is to detect pollution from ships.

Since the number and frequency of patrols that monitor and detect pollution from ships have increased, 97% more vessels have been monitored along the coastlines. In 2013-2014, the patrols recorded 44 releases of harmful pollutants by identified vessels into marine environments. The total of marine pollution incidents detected during that time was 214.

Wastewater Management

Every year, more than 150 billion litres of undertreated and untreated wastewater gets dumped into waterways in Canada. To reduce the risks posed by wastewater, the federal government together with provincial and territorial governments, Indigenous communities, and other interested parties, created national standards for the treatment of wastewater.

Since 2013, the metal mining sector has reported compliance of 99% with limits for metals, pH, and cyanide in wastewater. Within the pulp and paper sector, 96.2% of samples met the regulatory requirements for toxicity tests on fish, 99.9% met the requirements for biochemical oxygen demand, and 99.8% met the requirement for TSS.

How is the Quality of Water Measured?

There are a range of factors that determine the quality of water. When looking at the quality of water in lakes, rivers, and oceans, one of the key factors is the amount of dissolved oxygen in the water. When the oxygen level in a body of water is too low, it will not support the aquatic life. If the level of dissolved oxygen falls below 2mg per litre, it cannot support life in the water. With 2-4 mg per litre, some aquatic insects and fish can survive. The oxygen level needs to be between 7-11 mg per litre to best support aquatic life.

Another factor is the level of alkalinity in the water, which helps aquatic animals to keep within a healthy range of acidity. Higher concentrations also help the body of water to resist fast changes in pH levels. 10 mg per litre is considered a very low alkaline level, 51-150 g per litre is moderate, while over 300 mg per litre is very high.

The conductivity of water refers to its ability to conduct electricity. The higher the conductivity, the more chemicals there are dissolved in the water. These chemicals include nitrate, sulfate, magnesium, sodium, calcium, chloride, and iron. While some bodies of water have naturally higher conductivity, unusually high readings could mean the aquatic life is in danger.

The pH level of the water is also important for the survival of aquatic life. In freshwater sources, such as rivers and lakes, the optimum level of pH is around 7.4. However, levels ranging from 6 to 8 are normal. If there are large changes in the pH levels, it could pose a serious risk to the survival of the fish and other aquatic life. In seawater, the pH level is higher, around 9.


Canada has one of the largest freshwater sources in the world and ranks 22nd for its drinking water quality. Between 2018 and 2020, the water quality at 45% of Canadian water monitoring stations was excellent. However, at 2% of the monitoring stations the quality was poor.

While the government has taken the lead in improving and maintaining water quality in Canada, it is up to every Canadian to use water more wisely. That way we can continue to enjoy the economic, social, and environmental benefits Canada’s freshwater supply provides.

Frequently Asked Questions

You can safely drink tap water in Canada. The country ranks 22nd in the world for its drinking water quality.

Canadians use 1,687 gallons of water per day. This is the third highest rate in the world after the United Arab Emirates and the United States.

There are several ways you can save water. Some ideas include turning the tap off when brushing your teeth, fixing leaky taps, taking shorter showers, only running the washing machine and dishwasher when they are full, reducing food waste, and catching rainwater.