Water Quality

​​​​​​​Water quality standards are the foundation of the water quality-based control program mandated by the federal Clean Water Act. Water quality standards define goals for surface waters in Oregon by designating uses, setting criteria to protect those uses and establishing provisions to protect water quality from pollutants.

DEQ establishes water quality criteria for toxic pollutants to protect both aquatic life and human health. These criteria are established to protect surface waters for aquatic life use, to allow Oregonians to consume fish and shellfish, and to use state waters for drinking water supply without adverse health effects. DEQ develops its water quality criteria based on EPA recommended criteria and toxicity data, but sometimes modifies the federal criteria to protect local species and populations. 

Current toxics standards

    • Aquatic life criteria - Table 30

    • Human health criteria -Table 40

    • Guidance values ONLY - Table 31

Aquatic life tox​​ics criteria

Aquatic life criteria are established to protect fish, shellfish, and wildlife. They represent the level of a chemical that can be present in a waterbody that makes harm to plants and animals unlikely. Aquatic life criteria may apply to freshwater and/or saltwater, and they account for both short-term (acute) and long-term (chronic) exposures.

​On Jan. 31, 2013, EPA disapproved a number of aquatic life criteria that the Environmental Quality Commission adopted in 2004. The pollutants included pesticides, cadmium (acute only), copper, ammonia and aluminum. Since 2013, DEQ adopted and EPA approved revisions to several of the disapproved criteria. See “Parameter Specific Information" below for more details on the current status of aquatic life criteria for pollutants disapproved by EPA in 2013.

Additional resources

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Human health toxics criteria

Human health criteria establish goals for Oregon's surface waters, including protecting sources of drinking water and helping ensure that fish from Oregon's waters are safe to eat. These criteria establish chemical levels in water and tissue that are unlikely to cause significant risk to people. Human health criteria are designed to protect people from the long term (i.e. lifetime) effects of pollution exposure. ​​

On Oct. 17, 2011, the U.S. Environmental Protection Agency approved revisions to Oregon's water quality standards designed to reduce or prevent toxic pollutants in Oregon waterways. These standards establish goals for Oregon's surface waters, including protecting sources of drinking water and helping ensure that fish from Oregon's waters are safe to eat. EPA's approval makes the revised state standards, including new NPDES permitting implementation policies, effective for state and federal Clean Water Act programs.

In conjunction with revisions to the human health standards, DEQ revised certain water quality rules to clarify procedures and create new permitting tools (i.e. intake credits, a site-specific background pollutant criterion, and a revised variance rule) for implementing the standards. For more information about these revisions, please see the fact sheet and internal management directives below. 

Additional resources

DEQ staff developed the following documents to support this rulemaking. They are intended to help the public understand the various policy and technical issues raised, alternatives discussed, and the DEQ recommendations resulting from discussions with the rulemaking workgroups.

Rulemaking Issue Papers

​​Parameter specific information