Regional water quality in Canadian rivers

Access PDF (1.33 MB)

River plants and animals rely on clean water to maintain healthy populations. The quality of water and the health of rivers depend on how people develop and use the surrounding land.

Key results

  • Good or excellent water quality was more common on rivers draining into the Atlantic Ocean and the Mackenzie River
  • Marginal or poor water quality was more common on rivers draining into the Great Lakes and St. Lawrence River

Regional water quality, Canada, 2013 to 2015 period

Map of Canada shows the state of water quality at 197 water quality monitoring sites. Inset column charts show the sites grouped by the major river or ocean system into which they drain - Long description below.

Long description

The map of Canada shows the state of water quality at 197 water quality monitoring sites; the 178 core sites for southern Canadian rivers and 19 additional monitoring sites in the Mackenzie River and Pacific Ocean regions.

The inset column charts show the monitoring sites grouped by the major river or ocean system into which they drain: the Atlantic Ocean, the Great Lakes and St. Lawrence River, Hudson Bay, the Mackenzie River and the Pacific Ocean. Of the 46 monitoring sites on rivers draining into the Atlantic Ocean, 7% had excellent water quality, 63% had good water quality, 24% had fair water quality, 7% had marginal water quality, and no monitoring sites had poor water quality. Of the 59 monitoring sites draining into the Great Lakes and St. Lawrence River, 3% had excellent water quality, 27% had good water quality, 41% had fair water quality, 24% had marginal water quality, and 5% of monitoring sites had poor water quality. Of the 46 monitoring sites draining into Hudson Bay, 4% had excellent water quality, 30% had good water quality, 41% had fair water quality, 24% had marginal water quality, and no monitoring sites had poor water quality. Of the 21 monitoring sites on rivers draining into the Mackenzie River, 10% had excellent water quality, 57% had good water quality, 24% had fair water quality, 10% had marginal water quality, and no monitoring sites had poor water quality. Of the 25 monitoring sites draining into the Pacific Ocean, 4% had excellent water quality, 40% had good water quality, 44% had fair water quality, 8% had marginal water quality, and 4% of monitoring sites had poor water quality.

Data for this chart
Regional water quality, Canada, 2013 to 2015 period
Water quality categoryAtlantic Ocean (number of sites)Great Lakes and St. Lawrence River (number of sites)Hudson Bay (number of sites)Mackenzie River (number of sites)Pacific Ocean (number of sites)
Excellent32221
Good2916141210
Fair112419511
Marginal3141122
Poor03001
Total4659462125
Water quality categoryAtlantic Ocean (percentage of sites)Great Lakes and St. Lawrence River (percentage of sites)Hudson Bay (percentage of sites)Mackenzie River (percentage of sites)Pacific Ocean (percentage of sites)
Excellent734104
Good6327305740
Fair2441412444
Marginal72424108
Poor05004
Total100100100100100

Note: Percentages may not add up to 100 due to rounding.

Download data file (Excel/CSV; 1.34 KB)

Access federal data files

Table descriptions (CSV; 10.5 KB)

Variable information (CSV; 16.5 KB)

Federal raw data (CSV; 35.4 MB)

Federal trend data (CSV; 184 KB)

Federal water quality index scores (CSV; 357 KB)

Navigate data using the interactive map
How this indicator was calculated

Note: Water quality was assessed at 197 monitoring sites across Canada using the Canadian Council of Ministers of the Environment's water quality index. The additional monitoring sites improve the coverage of the northern portions of the McKenzie River and Pacific Ocean regions.
Source: Data assembled by Environment and Climate Change Canada from federal, provincial, territorial and joint water quality monitoring programs.

More Information

Water quality varies widely across Canada. For the 2013 to 2015 period:

  • The highest percentage of monitoring sites rated good or excellent was found on rivers draining into the Atlantic Ocean (70%) and the Mackenzie River (67%). Good or excellent water quality was found at undeveloped monitoring sites with very little human development upstream of them. The Atlantic Ocean and Mackenzie River regions have the highest proportion of undeveloped monitoring sites in Canada.
  • The highest proportion of monitoring sites rated marginal or poor was found on rivers draining into the Great Lakes and St. Lawrence River (29%). This area has a lot of urban development and agriculture.

Atlantic Ocean

Key results

  • Most monitoring sites in the Atlantic Ocean region are in undeveloped areas and have good or excellent water quality
  • Water quality at monitoring sites close to cities, agriculture and/or mining (mixed pressures) tend to have worse water quality

Map of Canada showsing the state of freshwater quality draining into the Atlantic Ocean and column chart showing ratings grouped into 4 categories - Long description below.

Long description

The map of Canada shows the state of freshwater quality at 46 water quality monitoring sites on rivers draining into the Atlantic Ocean.

The column chart presents water quality ratings grouped into 4 land use categories: agriculture, mining, mixed pressures and undeveloped for the 2013 to 2015 period. Excellent and good water quality was found more often in undeveloped areas. Marginal water quality was found more often at monitoring sites with mixed land use pressures.

Data for this chart
Water quality by land use category, Atlantic Ocean region, 2013 to 2015 period
Land use categoryPoor (number of sites)Marginal (number of sites)Fair (number of sites)Good (number of sites)Excellent (number of sites)
Agriculture00330
Mining00230
Mixed pressures03200
Undeveloped004233
Total0311293
Land use categoryPoor (percentage of sites)Marginal (percentage of sites)Fair (percentage of sites)Good (percentage of sites)Excellent (percentage of sites)
Agriculture00770
Mining00470
Mixed pressures07400
Undeveloped009507
Total0724637

Note: Percentages may not add up to 100 due to rounding.

Download data file (Excel/CSV; 1.26 KB)

Access federal data files

Table descriptions (CSV; 10.5 KB)

Variable information (CSV; 16.5 KB)

Federal raw data (CSV; 35.4 MB)

Federal trend data (CSV; 184 KB)

Federal water quality index scores (CSV; 357 KB)

Navigate data using the interactive map
How this indicator was calculated

Note: Water quality by land use category was assessed at 46 monitoring sites on rivers draining into the Atlantic Ocean using the Canadian Council of Ministers of the Environment's water quality index.
Source: Water quality data were assembled by Environment and Climate Change Canada from existing federal, provincial and joint water quality monitoring programs. Population, mining and land cover statistics for each site's drainage area were provided by Statistics Canada.

Additional information

Along the east coast of Canada, all rivers drain into the Atlantic Ocean. This region includes Nova Scotia, New Brunswick, Prince Edward Island, and Newfoundland and Labrador, along with part of eastern Quebec.

For the 2013 to 2015 period, water quality for 46 monitoring sites on rivers draining into the Atlantic Ocean was rated:

  • excellent or good at 70% of monitoring sites
  • fair at 24% of sites
  • marginal at 7% of sites

Water quality tends to be good to excellent in this region of Canada because large areas are undeveloped, particularly in Labrador. The region is home to approximately 2.4 million people, or 7% of Canada's population. The majority of them live in New Brunswick, Nova Scotia and on the island of Newfoundland.

Agriculture is mainly found in Prince Edward Island, Nova Scotia's Annapolis Valley, and New Brunswick where the soil and climate are suitable. Fertilizers and pesticides used to help crops grow can wash into nearby rivers, impacting water quality in these areas.

Mining is one of the region's largest industries. In Newfoundland and Labrador, iron ore, nickel, copper, cobalt and gold are mined. New Brunswick and Nova Scotia have many active aggregates, limestone and gypsum mines. Water pollution from mine effluent released to rivers and leaching from tailings and waste rock enclosures can have a local impact on water quality. Closed or abandoned metal mines may still be releasing substances to the water.

Between the first year of data collection and 2015, water quality has improved on the Terra Nova River in Newfoundland and Labrador and on the Roseway River in Nova Scotia. These 2 monitoring sites have very little development around them. Water quality has deteriorated on the Aroostook River and the Saint John River in New Brunswick in areas where there is agriculture and industrial development. There has been no change in water quality at the remaining 42 sites.

Great Lakes and St. Lawrence River

Key results

  • Water quality on rivers draining into the Great Lakes and St. Lawrence River ranges from fair to poor in southwestern Ontario and along the St. Lawrence River between Montreal and Quebec City. It is good or excellent in eastern Ontario.
  • Water quality at monitoring sites close to cities and agriculture (mixed pressures) tend to have worse water quality.

Water quality by land use category, Great Lakes and St. Lawrence River region, Canada, 2013 to 2015 period

Map of Canada showing the state of freshwater quality rivers draining into the Great Lakes and St. Lawrence River and column chart showing ratings grouped into 4 categories - Long description below.

Long description

The map of Canada shows the state of freshwater quality at 59 water quality monitoring sites on rivers draining into the Great Lakes and St. Lawrence River.

The column chart presents water quality ratings grouped into 4 land use categories: agriculture, mining, mixed pressures and undeveloped. Good and excellent water quality was found more often in undeveloped areas. Poor and marginal water quality was found more often at monitoring sites with mixed land use pressures.

Data for this chart
Water quality by land use category, Great Lakes and St. Lawrence River region, 2013 to 2015 period
Land use categoryPoor (number of sites)Marginal (number of sites)Fair (number of sites)Good (number of sites)Excellent (number of sites)
Agriculture05521
Mining01420
Mixed pressures381340
Undeveloped00281
Total31424162
Land use categoryPoor (percentage of sites)Marginal (percentage of sites)Fair (percentage of sites)Good (percentage of sites)Excellent (percentage of sites)
Agriculture08832
Mining02730
Mixed pressures5142270
Undeveloped003142
Total52441273

Note: Percentages may not add up to 100 due to rounding.

Download data file (Excel/CSV; 1.31 KB)

Access federal data files

Table descriptions (CSV; 10.5 KB)

Variable information (CSV; 16.5 KB)

Federal raw data (CSV; 35.4 MB)

Federal trend data (CSV; 184 KB)

Federal water quality index scores (CSV; 357 KB)

Navigate data using the interactive map
How this indicator was calculated

Note: Water quality by land use category was assessed at 59 monitoring sites on rivers draining into the Great Lakes or St. Lawrence River using the Canadian Council of Ministers of the Environment's water quality index.
Source: Water quality data were assembled by Environment and Climate Change Canada from existing federal, provincial and joint water quality monitoring programs. Population, mining and land cover statistics for each site's drainage area were provided by Statistics Canada.

Additional information

For the 2013 to 2015 period, water quality for 59 monitoring sites on rivers draining into the Great Lakes and St. Lawrence River was rated:

  • excellent or good at 31% of monitoring sites
  • fair at 41% of sites
  • marginal at 24% of sites
  • poor at 5% of sites

Home to almost 60% of Canadians, almost 20 million people, the Great Lakes and St. Lawrence River region contains 6 of the country's 10 largest cities: Toronto, Montreal, Ottawa-Gatineau, Quebec City, Hamilton, and Kitchener-Waterloo. Most human activity in this area is associated with urbanization. The impact of increasing population density can be seen in the diminished water quality at monitoring sites on rivers.

Fertile soils and a relatively mild climate combine to create productive agricultural land in the Great Lakes and St. Lawrence River region. Fertilizers used to help crops grow and manure from livestock can wash into nearby rivers impacting water quality in these areas. Agricultural land is steadily being covered by cities changing the stresses on water quality in the region.

Mining in the region is dominated by feldspar and quartz mines. Feldspar is a type of quartz used to make glass.

Between the first year of data collection and 2015, water quality has improved on the Gatineau River, the Bayonne River, the Saint-Charles River, the Saint François River and the Rivière du Nord in Quebec. These monitoring sites are mostly in areas where a lot of people live and have agriculture and mining in the area (mixed pressures). Water quality has deteriorated on the Credit River, the Nottawasaga River, the North Raisin River, the Gananoque River and the Fall River in Ontario. Land use at these monitoring sites is mixed pressures or agriculture. There was no change in water quality at the remaining 49 monitoring sites.

Hudson Bay

Key results

  • Water quality in rivers draining into Hudson Bay tends to be good or excellent close to the Rocky Mountains and north of Lake Winnipeg. It is in these regions that there is very little development.
  • Water quality tends to be fair or marginal where there is agriculture, or a mixture of agriculture and mining.

Water quality by land use category, Hudson Bay region, 2013 to 2015 period

Map of Canada showing the state of freshwater quality of rivers draining into Hudson Bay and a column chart showing ratings grouped into 4 categories - Long description below.
Long description

The map of Canada shows the state of freshwater quality at 46 water quality monitoring sites on rivers draining into Hudson Bay.

The column chart presents water quality ratings grouped into 4 land use categories: agriculture, mining, mixed pressures and undeveloped. Marginal water quality was found more often at monitoring sites with agriculture or mixed land use pressures around them.

Data for this chart
Water quality by land use category, Hudson Bay region, 2013 to 2015 period
Land use categoryPoor (number of sites)Marginal (number of sites)Fair (number of sites)Good (number of sites)Excellent (number of sites)
Agriculture051230
Mining00020
Mixed pressures06780
Undeveloped00012
Total01119142
Land use categoryPoor (percentage of sites)Marginal (percentage of sites)Fair (percentage of sites)Good (percentage of sites)Excellent (percentage of sites)
Agriculture0112670
Mining00040
Mixed pressures01315170
Undeveloped00024
Total02441304

Note: Percentages may not add up to 100 due to rounding.

Download data file (Excel/CSV; 1.26 KB)

Access federal data files

Table descriptions (CSV; 10.5 KB)

Variable information (CSV; 16.5 KB)

Federal raw data (CSV; 35.4 MB)

Federal trend data (CSV; 184 KB)

Federal water quality index scores (CSV; 357 KB)

Navigate data using the interactive map
How this indicator was calculated

Note: Water quality by land use category was assessed at 46 sites on rivers draining into the Hudson Bay using the Canadian Council of Ministers of the Environment's water quality index.
Source: Water quality data were assembled by Environment and Climate Change Canada from existing federal, provincial and joint water quality monitoring programs. Population, mining and land cover statistics for each site's drainage area were provided by Statistics Canada.

Additional information 

For the 2013 to 2015 period, water quality for 46 monitoring sites on rivers draining into Hudson Bay was rated:

  • excellent or good at 35% of monitoring sites
  • fair at 41% of sites
  • marginal at 24% of sites

The Nelson River originates at the northern tip of Lake Winnipeg and flows into the south-western corner of Hudson Bay. Its tributaries drain over 1 million km2 of land starting in the Rocky Mountains running through the Prairies and into Lake Winnipeg. Most of the 5.5 million people in the region live in its 5 major cities.

The prairies are the most altered landscape in Canada. Water quality in this region reflects the extensive human development. Agriculture covers almost all the land in the Prairies. Mining, particularly the production of potash and fuels, is the second most important industry. Water quality tends to be worse where rivers run through agricultural and mining areas.

From the first year of data collection to 2015, water quality has improved on the North Saskatchewan River in Alberta, the Red Deer River, the South Saskatchewan River, and the North Saskatchewan River in Saskatchewan and the Pembina River, the Saskatchewan River, and Cooks Creek in Manitoba. Land use at these sites is either agriculture alone or a mix of agriculture and mining (mixed pressures). There has been no change in water quality at the remaining 39 sites.

Mackenzie River

Key results

  • Water quality in the Mackenzie River region is generally excellent
  • Water quality in the southern portion of the region is impaired by mining and oil and gas activity

Water quality by land use category, Mackenzie River region, 2013 to 2015 period

Map of Canada showing the state of freshwater quality of rivers draining into the Mackenzie River and a column chart showing ratings grouped into 4 categories - Long description below.
Long description

The map of Canada shows the state of freshwater quality at 18 water quality monitoring sites on rivers draining into the Mackenzie River.

The column chart presents water quality ratings grouped into 4 land use categories: agriculture, mining, mixed pressures and undeveloped. Good and excellent water quality was found more often in undeveloped areas. Marginal water quality was found more often at monitoring sites with mining in the area.

Data for this chart
Water quality by land use category, Mackenzie River region, 2013 to 2015 period
Land use categoryPoor (number of sites)Marginal (number of sites)Fair (number of sites)Good (number of sites)Excellent (number of sites)
Agriculture00000
Mining01420
Mixed pressures00000
Undeveloped00092
Uncategorized01110
Total025122
Land use categoryPoor (percentage of sites)Marginal (percentage of sites)Fair (percentage of sites)Good (percentage of sites)Excellent (percentage of sites)
AgricultureFootnote [A]00000
MiningFootnote [A]0622110
Mixed pressuresFootnote [A]00000
UndevelopedFootnote [A]0005011
Uncategorizedn/an/an/an/an/a
Total010245710

 Note: n/a = not applicable. Percentages may not add up to 100 due to rounding.

Download data file (Excel/CSV; 1.44 KB)

Access federal data files

Table descriptions (CSV; 10.5 KB)

Variable information (CSV; 16.5 KB)

Federal raw data (CSV; 35.4 MB)

Federal trend data (CSV; 184 KB)

Federal water quality index scores (CSV; 357 KB)

Navigate data using the interactive map
How this indicator was calculated

Note: Water quality was assessed at 21 sites on rivers draining into the Mackenzie River using the Canadian Council of Ministers of the Environment's water quality index. Three sites have not had their land use categorized and are not included in this chart.
Source: Water quality data were assembled by Environment and Climate Change Canada from existing federal, provincial, territorial and joint water quality monitoring programs. Population, mining and land cover statistics for each site's drainage area were provided by Statistics Canada.

Additional information 

For the 2013 to 2015 period, water quality for 21 monitoring sites on rivers draining into Mackenzie River was rated:

  • excellent or good at 67% of monitoring sites
  • fair at 24% of sites
  • marginal at 10% of sites

The Mackenzie River watershed is the largest in Canada, covering nearly 20% of the country and is one of the least developed. Its two largest tributaries, the Peace River and the Athabasca River, drain much of north-central Alberta and the Rocky Mountains in northern British Columbia. The majority of the 450 000 people living in the watershed live in the southern portions of the watershed.

Much of the watershed consists of unbroken wilderness. The heaviest land use in the region is oil and gas extraction in central Alberta. This land use results in water quality in these areas being degraded relative to water in the undeveloped parts of the watershed.

Between the first year of data collection and 2015, water quality has not changed in this region.

Pacific Ocean

Key results

  • Water quality in rivers draining into the Pacific Ocean is generally good or excellent
  • Fair, marginal or poor water quality is found where there is mining

Water quality by land use category, Pacific Ocean region, 2013 to 2015 period

Map of Canada showing the state of freshwater quality of rivers draining into the Pacific Ocean and a column chart showing ratings grouped into 4 categories - Long description below.
Long description

The map of Canada shows the state of freshwater quality at 20 water quality monitoring sites on rivers draining into the Pacific Ocean.

The column chart presents water quality ratings grouped into 4 land use categories: agriculture, mining, mixed pressures and undeveloped. Good and excellent water quality was found more often in undeveloped areas. Poor and marginal water quality was found more often at monitoring sites with mining in the area.

Data for this chart
Water quality by land use category, Pacific Ocean region, 2013 to 2015 period
Land use categoryPoor (number of sites)Marginal (number of sites)Fair (number of sites)Good (number of sites)Excellent (number of sites)
Agriculture00100
Mining12410
Mixed pressures00000
Undeveloped00281
Uncategorized00410
Total1211101
Land use categoryPoor (percentage of sites)Marginal (percentage of sites)Fair (percentage of sites)Good (percentage of sites)Excellent (percentage of sites)
AgricultureFootnote [A]00500
MiningFootnote [A]5102050
Mixed pressuresFootnote [A]00000
UndevelopedFootnote [A]0010405
Uncategorizedn/an/an/an/an/a
Total4844405

Note: n/a = not applicable. Percentages may not add up to 100 due to rounding.

Download data file (Excel/CSV; 1.50 KB)

Access federal data files

Table descriptions (CSV; 10.5 KB)

Variable information (CSV; 16.5 KB)

Federal raw data (CSV; 35.4 MB)

Federal trend data (CSV; 184 KB)

Federal water quality index scores (CSV; 357 KB)

Navigate data using the interactive map
How this indicator was calculated

Note: Water quality was assessed at 25 monitoring sites on rivers draining into the Pacific Ocean using the Canadian Council of Ministers of the Environment's water quality index. Five sites are not included in the chart; their land use is not categorized because they are close to the Canada-United States border or the ocean.
Source: Water quality data were assembled by Environment and Climate Change Canada from existing federal, provincial, territorial and joint water quality monitoring programs. Population, mining and land cover statistics for each site's drainage area were provided by Statistics Canada.

Additional information 

For the 2013 to 2015 period, water quality for 25 monitoring sites on rivers draining into the Pacific Ocean was rated:

  • excellent or good at 44% of monitoring sites
  • fair at 44% of sites
  • marginal at 8% of sites
  • poor at 4% of sites

The landscape through which rivers draining into the Pacific Ocean flow varies from large areas with little to no development to one of Canada's largest cities, Vancouver. Roughly 4.4 million people, or 16% of Canadians, live in the watershed.

In the Okanagan Valley, soil conditions and climate are favourable for orchards, vineyards and cash crops. Cattle ranching are dominant throughout much of the other interior plateau and valley lands.

Mining is one of the region's largest industries. Coal, lead, zinc, copper, gold, silver, molybdenum and other precious metals are actively mined within the watershed. Soil erosion, water pollution from mine effluent released to rivers, and seepage from tailings and waste rock impoundments can have an impact on water quality.

Between the first year of data and 2015, water quality has improved at the Pend d'Oreille River, the Skeena River, the Thompson River, the Kootenay River, the Columbia River, and the Kettle River in British Columbia and declined at the Quinsam River, the Elk River, and the Fraser River. All of these monitoring sites had either no development upstream or had a mix of agriculture, mining and/or cities. There has been no change in water quality at the remaining 16 sites.

About the indicator

What does the indicator measure

This indicator provides a measure of the ability of rivers across Canada to support plants and animals. At each monitoring site, water quality measurements are compared to water quality guidelines to create a rating for the site. If measured water quality is below the guidelines, it can be considered a healthy ecosystem.

Water quality at a monitoring site is considered excellent when substances in a river are very rarely measured above their guidelines. Conversely, water quality is rated poor when measurements are usually above their guidelines, sometime by a wide margin.

Why is this indicator important

Clean freshwater is an essential resource. It protects aquatic plant and animal biodiversity. We drink it, use it for manufacturing, energy production, irrigation, swimming, boating and fishing. Degraded water quality damages the health of all freshwater ecosystems, such as rivers, lakes, reservoirs and wetlands. It can also disrupt fisheries, tourism and agriculture.

This indicator provides information about the state of surface water quality across Canada to support water resource management. It is used to provide information about the state of water quality for the Canada Water Act report and Environment and Climate Change Canada's annual departmental performance reports. It is also used to assess progress toward the 2016–2019 Federal Sustainable Development Strategy.

What are the related indicators

The Water quality in Canadian rivers indicator provides a summary of the state and trends in water quality in Canada at the national level.

The Nutrients in the St. Lawrence river and Nutrients in Lake Winnipeg indicators report the status of total phosphorus and total nitrogen concentrations in those two ecosystems.

The Phosphorus levels in the offshore waters of the Great Lakes reports on the state of and trends in total phosphorus concentrations in the open waters of the Canadian Great Lakes.

FSDS icon. Pristine lakes and rivers. Pristine lakes and rivers

This indicator supports the measurement of progress towards the following 2016–2019 Federal Sustainable Development Strategy long-term goal: Clean and healthy lakes and rivers support economic prosperity and the well-being of Canadians.

Access PDF (1.33 MB)

Date modified: