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Rule Making

Water Quality Standards for Protecting Human Health
(Fish consumption rates)
Chapter 173-201A WAC


Following extensive outreach, we adopted a water quality standards rule on August 1, 2016, that updates surface water quality standards to include human health criteria and updated tools to implement the standards.

Under the federal Clean Water Act, EPA has 60 days to approve, or 90 days to disapprove, the state rule.

Protects health

This rule maintains a more protective cancer risk rate and is in keeping with the governor's directive from October 2015. It aims to protect the health of Washington’s people, fish and the economy. It provides a foundation for our ongoing progress to reduce and control toxics in the environment as we continue to work with researchers and manufacturers to find safer chemical alternatives, eliminating these toxics at the source.


Our new adopted rule helps the state maintain control over how to meet federal requirements to ensure we are protecting human health while providing businesses and local government sensible tools to comply with updated standards.

EPA rule

The US Environmental Protection Agency (EPA) issued a proposed rule on September 14, 2015 that revises the current federal Clean Water Act human health water quality criteria applicable to waters under the state of Washington’s jurisdiction. EPA has not adopted this rule.

Compare Ecology's and EPA's proposed rules


Both the adopted state rule and EPA proposed rules agree that water quality standards should be based on a daily average fish consumption rate of 175 grams per day and a one-in-one-million cancer risk rate.


The state's new rule offers implementation tools to wastewater dischargers to provide them time to come into compliance while working on reducing toxics in their waste streams. EPA's rule proposal does not contain these options.

EPA's proposed rule contains stringent limits for PCBs and arsenic, and adds a new limit for methyl mercury that will be difficult for Washington dischargers to meet. Our adopted rule maintains the current standards, as proposed in our initial rule, for PCBs. Criteria for mercury would remain under federal regulation. Arsenic would align with the federal Safe Drinking Water Act standard.

Ecology's rulemaking process


Last updated August 2016



Becca Conklin



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EPA draft rule for Washington

Ecology's comments on EPA's draft rule for Washington

Archival Rule Documents

State Law

Approved Surface Water Quality Standards