Instream Flow Laws and Rules

An October 2016 Washington State Supreme Court case impacts permit-exempt well use, which may affect some of the information provided on this page.

Resources and Studies  

This webpage provides information on the legal basis for setting instream flows, and a general look at developing current instream flow/water management rules.

Terms in green are linked to a glossary.

Instream flows: stream flow regimes set in rule

Authority for setting flows comes primarily from state statutes.  An instream flow is a water right for fish and other instream resources.  Ecology is directed by state law to establish instream flows at levels that protect and preserve instream resources.

Setting instream flows does not put water in streams.  They are set to protect instream resources from future withdrawals.

When stream flows are set in rule, the effective date (also called a "priority date") is thirty days after the date of rule adoption.  The rules only affect water uses started after the effective date of the rule; they do not affect uses existing prior to the rule.

Developing instream flow/water resource management rules

While we still tend to refer to the regulations developed since 2000 as “instream flow rules,” it is more accurate to call them “water resource management rules.”  The rules currently being developed are much more complex and comprehensive than their counterparts in the 1970’s and early 1980’s.

In addition to setting instream flow levels, today’s rules include:

Progress on rule adoption varies considerably from watershed to watershed.  Many factors contribute to the complexity of developing instream flow/water management rules, and there are no easy solutions. These factors include:

Note: Through 2011 and 2012, all state agencies were under a rulemaking moratorium, per the Governor’s Executive Orders 10-06 and 11-03.  All “non-critical” rule development and adoption was suspended.  This also impacted our progress on rule development.

The water management rules being developed today focus on the protection of existing water rights and instream resources, while providing water for future urban and rural needs.

Authority for setting flows

Authority for setting flows is derived from state and federal statutes, and case law.  Setting flows also helps to satisfy federal and tribal law impacting water resources (quantity), water quality, and protection of instream resources, particularly fish.  The primary statutes relating to flows and flow setting are:

State statutes (laws)

Case law

Case law is created when the Courts interpret statutory law. Legal cases affect water resource management in Washington and are binding on Ecology, as is statutory law.

Federal statutes

Washington State must also follow federal law.

Tribal rights

The State of Washington must respect treaty obligations and collaborate with the governments of Native American tribes.  Many watersheds in Washington have established tribal treaty rights or pending tribal claims to water that relate directly to ensuring sufficient stream flows for fish.

Tribes have fishing rights in their historic “usual and accustomed areas.”  A right to productive salmon habitat is asserted along with the right to fish, meaning that flows to support productive fish stocks must be maintained in salmon-producing rivers and streams.  The effective date of flows to support salmon habitat and fish production has been characterized in court cases as “time immemorial,” making this the most senior of water rights in the state.

While an instream flow rule does not alter or affect these rights and claims, the development of instream flow recommendations represents an opportunity to consult tribal governments regarding the relationship between their rights and state instream flow rules.  By law, Ecology must consult with tribal governments when developing and evaluating instream flow recommendations.

There are 29 recognized tribes in Washington State.