The Provincial Water Quality Monitoring Network (PWQMN) collects information about the quality of stream-water from over 400 locations across Ontario.
Monitoring stream-water quality can help us understand the impacts of land-use activities on water quality, enabling us to make informed decisions about managing and protecting our water resources.
Land-use activities may include:
Stream-water monitoring also helps us measure the effectiveness of programs and policies that are designed to protect and restore the quality of our water resources.
Recently, special studies relating to agricultural and urban watersheds have included stream-water collection and analysis. This information will support source protection planning and the management of nutrients, pesticides and road salts.
Stream-water samples are collected by the ministry and its partners - Ontario's Conservation Authorities. Samples are brought to the ministry's laboratory for testing.
Consistent collection methods and laboratory analysis ensure comparable test results for locations across the province.
Samples from each monitoring location are tested for a consistent set of water quality indicators including:
At selected locations, additional samples are collected and tested for other indicators, such as metals and bacteria.
Measurements of qualities like temperature and pH are also taken in the field (during sample collection) using portable water quality meters.
The amount of water flowing in a stream is an important factor in determining stream-water quality and interpreting stream-water quality monitoring results. Stream flows are measured by the Water Survey of Canada.