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Standards for Water Body Health

Relationship between Water Quality Criteria and Water Quality Standards

Body of water with gray skies

Water Quality Standards

Water quality standards are regulations that include designated uses and water quality criteria to protect those uses. The criteria adopted and incorporated into the standards are the allowable concentrations of pollutants in State, Territory and authorized Tribal waters. These standards, which include water quality criteria, are adopted by the State, Territory or authorized Tribe and reviewed and approved or disapproved by EPA. For more information, visit EPA’s page describing water quality standards and the four components that make up water quality standards.

LEARN: What are Water Quality Standards?

Water Quality Criteria

Section 304(a)(1) of the Clean Water Act requires EPA to develop these criteria for water quality. EPA publishes human health and aquatic life criteria and is currently developing sediment and biological criteria. These criteria are complementary: each is designed to protect specific types of living organisms or ecological systems from the adverse effects of pollution. Water quality criteria are developed independently based on the best available scientific data and scientific judgments. The criteria are generally listed at some threshold concentration that, if exceeded, would cause harm to aquatic life, wildlife or human health. For many pollutants, EPA has developed recommendations and criteria. States, Territories and authorized Tribes may adopt EPA’s recommended values or adopt their own values based on appropriate data and information.