Site-Specific and Ambient Standards

Environment Protection Agency (EPA) water quality criteria are developed to be protective of aquatic life that could be present nationwide. This all-inclusive database may not be relevant to all situations. As such, EPA has provided guidance for modifying the national databases to develop site-specific standards. This allows for the application of standards that are more relevant to a specific site, but are still protective of that biological community.

When natural water quality exceeds standards, EPA guidance also allows for the calculation of site-specific standards based on the existing, or ambient conditions of a water body, if the exceedences are not affected by human activities.