SEPA laws and regulations: current & historical revisions

2026 legislative session: Ecology SEPA bills

During the 2026 session of the Washington Legislature, a couple bills were enacted related to the State Environmental Policy Act. The following information identifies these bills, including the changes they make to the law. 

Project Permits- Review Process (HB 2418)

Engrossed Second Substitute House Bill 2418 primarily makes changes to the Local Project Review Act, Chapter 36.70B RCW to streamline application review timelines by the local government but also adds a new section to SEPA Chapter 43.21C RCW and amends several other procedural laws.  

The one change to SEPA identifies new requirements for who acts as the responsible official representing local government. This change is found in Section 10 of the bill. It adds a new provision to SEPA that applies to Growth Management Act fully planning towns, cities and counties when they act as SEPA lead agency for a residential project. When such towns, cities and counties designate a responsible official for the local permit decisions for a residential project that same individual must also act as the SEPA responsible official. 

In addition to this one change in SEPA, several subsections were added to the Local Project Review Act, see RCW 36.70B.080, that exclude time from the project permit application timer, or removes days that do not count towards the deadline to issue a decision on a project permit application. These time exclusions include: 

• Any time a local government is waiting for another agency to take an action on a project component that impedes the issuance of the project permit decision. 
• Any time it takes to prepare a SEPA EIS once a determination of significance is issued.
• Any time it takes between the issuance of a final decision and the expiration of the applicable administrative appeal period. 

Renewable Energy-Taxes and Local Investments (HB1960)

Engrossed Third Substitute House Bill encourages renewable energy projects in Washington by providing tax incentives and resources to counties. The bill tasks the Washington State Department of Commerce (Commerce) to provide technical assistance to local governments on siting and design of renewable energy facilities in counties. As part of providing technical assistance, Commerce must develop and publish a model ordinance for counties to adopt that contains regulations for decommissioning wind facilities, consistency with the Growth Management Act and avoids adverse impacts to natural and cultural resources.  The bill also requires Commerce to implement SEPA for the publication of the model ordinance. 
 
Section 302 of the Bill amends SEPA by adding a new non-project exemption for counties in RCW 43.21C.525. The provision authorizes counties to adopt Commerce’s model ordinance without conducting a SEPA review. 

2025 legislative session: Ecology SEPA bills

During the 2025 session of the Washington Legislature, several bills were enacted related to the State Environmental Policy Act. The following information identifies these bills, including the changes they make to the law. 

Transit Oriented Development (HB 1491), effective July 27, 2025  

Third Substitute House Bill 1491 prioritizes increasing transit-oriented development within Washington cities. The addition to the State Environmental Policy Act (SEPA), RCW 43.21C.229, adds a new categorical exemption for residential and mixed-use density around transit station areas within cities managing their growth and development under the state Growth Management Act (GMA). The new exemption affects locations meeting the definition of a “station area” added to RCW 36.70A.030(51). Generally, these areas are located within one-half mile walking distance of a rail station area or within a quarter mile of a bus rapid transit stop. The categorical exemption is limited to the construction of multi-family residential buildings or mixed-use buildings containing a residential portion located within a zone that allows mixed-use development.  

This new categorical exemption is subject to the following exceptions to the exemptions  identified in WAC 197-11-800(1)(a); or in other words, if any of the following criteria apply to a commercial or residential construction project in a service area, the proposal it is not SEPA exempt: 

• The proposal includes other components that are not exempt from SEPA , see WAC 197-11-305(1)(b).
• The project is located wholly or partially on lands covered by water defined in WAC 197-11-756. These lands are surface water bodies in Washington, including wetlands, lakes, rivers and streams and saltwater bodies, and artificial water bodies like reservoirs, impoundments and channelized streams.

• The project requires an air emission permit not exempt under RCW 43.21C.0381; 
• The project requires a water discharge permit not exempt under RCW 43.21C.0383. This includes a project that disturbs five or more acres of land, or another water discharge permit issued by the state Department of Ecology. 
• The project requires a rezone that triggers a comprehensive plan amendment identified in WAC 197-11-800(6)(c).  

Designation of historic landmarks (HB 1576), effective July 27, 2025:

Substitute House Bill 1576 creates new processes and criteria for nominating and establishing property to be put on the historic register in Washington under the state Growth Management Act. The changes to SEPA add an appeal safe haven for cities and counties adopting ordinances, development regulations and other nonproject actions under the new law. The bill’s new language adds RCW 43.21C.495 identifying nonproject actions taken by cities and counties for consistency with sections 1 and 2 of the bill. These are not subject to SEPA administrative or judicial appeals. 

Energy Transformation Act (SB 5445), effective July 27, 2025: 

Engrossed Substitute Senate Bill 5445 encourages the development of distributed energy resources to support clean energy goals under the Clean Energy Transformation Act. The bill adds a new section to SEPA creating categorical exemptions for solar energy projects. Three types of projects are now categorically exempt:

• Small-scale projects on previously disturbed or developed lands
• Projects located over existing parking lots
• Solar energy projects located on landfills and reclaimed surface mines

Read the details below for specific criteria for each of the three new exemptions.

Growth Management Act – Housing Element (SB 5471), effective July 27, 2025:

Third Engrossed Senate Bill 5471 authorizes counties fully planning under the Growth Management Act (GMA) to allow for middle housing in unincorporated urban growth areas. 

Changes to SEPA include a new subsection to RCW 43.21C.495 providing an appeal safe haven to counties adopting non-project action implementing section 1 of the bill. The new language blocks all administrative and judicial appeals under SEPA for any locally adopted ordinance, resolution, development regulation or other non-project action taken by a GMA-fully-planning-county to incorporate the middle housing allowances into their planning and regulatory scheme. 

Growth Management Act- Comprehensive Plan Housing Element, (SB 5148), effective July 27, 2025

Engrossed Second Substitute Senate Bill 5148 establishes a new approval process with the state Department of Commerce for the housing element of comprehensive plans and associated housing development regulations for cities and counties fully planning under the Growth Management Act (GMA).

The bill adds a new subsection to RCW 43.21C.495 identifying a SEPA appeal safe haven for cities and counties adopting nonproject actions implementing the housing element requirements in RCW 36.70A.070(2). The new section blocks all administrative and judicial appeals under SEPA for adoption of ordinances, development regulations, amendments to development regulations for compliance with the housing element under GMA. 

The bill also identifies compliance with SEPA as criteria for approval by Commerce for the housing element and associated housing regulations.

State Transportation System (SB 5801), effective July 27, 2027: 

Engrossed Substitute Senate Bill 5801 enacts comprehensive changes to several laws for ongoing development and maintenance of the state transportation system.

Section 605 of the bill adds a new section to the State Environmental Policy Act (SEPA) that applies to transit projects when a “detailed statement” or Final Environmental Impact Statement (Final EIS) has been prepared by a transit agency. The new section identifies two different scenarios for compliance with SEPA when a transit agency prepares a Final EIS: One for a SEPA Final EIS and one for a Final EIS under the National Environmental Policy Act..

Average time to complete an environmental impact statement

Every two years, Ecology is required to submit a report to the legislature documenting the average time it takes to complete a final environmental impact statement under SEPA.  The report is required under 43.21C.0311(2). You can find these reports on our publications page. 

State Environmental Policy Act case law summary:  

The following summaries are a collection of court decisions affecting Chapter 43.21C RCW. This is not a complete list of all applicable opinions on SEPA. To find the complete written opinions related to these summaries, we recommend searching Washington State Courts