guidelines and Tolerances

Canada’s water quality guidelines include both national and provincial/territorial standards. The Canadian Council of Ministers of the Environment (CCME) and Environment and Climate Change Canada (ECCC) set national guidelines to protect aquatic life, drinking water, and recreational water use.

However, provinces and territories have their own guidelines, which can be stricter (or less so) or more region-specific. In some cases, guidelines are over 20 years old or missing for certain parameters, contaminants. Where no provincial or territorial guidelines exist, CCME and federal standards serve as the default reference.

To make water quality guidelines more accessible, we’ve compiled them into a user-friendly spreadsheet—helping you apply them to your own assessments with ease.

Benthic invertebrates are widely used as bioindicators to assess water quality. Different species have varying tolerances to pollution, with sensitivity scores typically ranging from 0 (highly sensitive) to 10 (highly tolerant)​.

For the Freshwater Health Assessment, tolerance values were assigned primarily at the family level, using well-established datasets such as the Hilsenhoff Biotic Index (HBI) and EPA regional tolerance values​. These scores help classify streams based on their ecological condition.

Since regional differences affect species composition, tolerance values were adjusted for specific Canadian watersheds where necessary. However, in northern zones and certain central regions, the HBI was found to be less reliable, as cold-adapted species naturally have higher tolerance scores, potentially misrepresenting ecosystem health.​

For transparency, these tolerance scores and methodologies have been compiled into an accessible spreadsheet to aid in independent water quality assessments.