SEPA laws and regulations: current & historical revisions

Ecology is responsible for overseeing state rules that implement the State Environmental Policy Act (SEPA).

Find full text of SEPA and state rules:

2024 Legislature : Ecology SEPA bills

No changes were made to the State Environmental Policy Act during the 2024 legislative session.

Questions? Contact Sarah Cassal, sarah.cassal@ecy.wa.gov, 360-407-6922.

2023 Legislature: Ecology SEPA bills

During the 2023 Legislative session, several bills were enacted related to the State Environmental Policy Act (SEPA). The following information identifies these bills and briefly explain the changes they make. Questions? Contact Fran Sant, fran.sant@ecy.wa.gov (360) 529-6375.

Climate Change and Land Use Planning (HB 1181)

Engrossed Second Substitute House Bill 1181 adds a climate change mitigation and resiliency goal to the Growth Management Act (GMA) for cities and counties to implement. The bill adds a new section to SEPA RCW 43.21C.497 making nonproject actions related to implementing new GMA requirements immune from administrative and judicial appeals.

Commerce planning guidance to implement planning requirements under E2SHB 1181.

Engrossed Second Substitute House Bill 1181 adds a climate change mitigation and resiliency goal to the GMA. The bill adds a climate change and resiliency element to the list of elements that counties and larger cities fully planning under the GMA must include. The bill also updates requirements for several existing comprehensive plan elements to address climate change considerations (including Capital Facilities, Land Use, Park and Recreation, Transportation and Utilities elements) and provides direction to address vulnerable populations and overburdened communities.

The new climate change element in local comprehensive plans must include a greenhouse gas emissions mitigation subelement that identifies actions each jurisdiction will take to reduce greenhouse gas emissions and vehicle miles traveled. The Department of Commerce will publish guidelines that specify actions counties and cities have available to update and will update these measures every 5 years. Notably, the bill exempts actions related to the GHG emissions reductions element from appeals under the State Environmental Policy Act. Counties and cities have the option to submit the GHG mitigation subelement to Commerce for approval.

The new climate change element must also include a resiliency subelement that reduces adverse impacts of climate change on communities and ecological systems. Counties and cities are authorized to adopt natural hazard mitigation plans by reference to meet these requirements, provided they comply with the bill.

Commerce, in partnership with other state agencies, is directed to adopt rules and guidance to creates a model element for climate change and resiliency. Commerce published its first guidance documents in July 2023. They will provide updated guidance in December 2023.

Commerce draft guidance describes steps in updating climate element

HB 1181 also directs us to update the states's Shoreline Master Program (SMP) guidelines to address the impact of sea level rise and increased storm severity on people, property, and shoreline natural resources and the environment. It also adds consideration of climate change impacts to the list of elements that must be contained in optional comprehensive flood hazard management plans.

Implementation notes: Commerce began developing guidance to implement E2SHB 1181 with a 2022 legislative proviso. We will update state SMP rules to incorporate consideration of climate change by late 2025. Jurisdictions seeking to start the technical work to support SMP climate change updates may apply for competitive grants starting in July 2023.

SEPA Categorical Exemption for Infill Housing (SB 5412)

Second Substitute Senate Bill 5412 amends SEPA RCW 43.21A.229 to allow proposed housing within urban growth boundaries to rely on environmental reviews completed at the comprehensive planning level rather than the individual project level. Provided certain criteria are met the bill creates a new SEPA categorical exemption for residential housing projects within cities and “middle housing” projects in unincorporated urban growth areas. To be eligible a housing project must be consistent with all development regulations adopted under the GMA.

Before adopting the exemption, cities and counties must prepare an environmental analysis regarding the density and intensity of housing allowed in their jurisdiction, including transportation impacts. The analysis must document that the requirements for environmental analysis, protection, and mitigation for impacts to elements of the environment have been adequately addressed. The city or county must document they have consulted with the Washington State Department of Transportation (WSDOT) on impacts to state-owned transportation facilities, including whether mitigation is necessary for impacts. Jurisdictions will likely incorporate the new exemption as part of the upcoming periodic GMA update cycle.

A special provision unique to Seattle, which categorically exempts residential development from SEPA review.

Implementation notes: The bill does not direct us to update the SEPA Rules. We will coordinate with Commerce, WSDOT, counties, cities and others on guidance for local governments.

Guidance for SB 5412

Middle Housing, Accessory Dwelling Units and Existing Buildings (HB 1110)

Engrossed Second Substitute House Bill 1110 amends both GMA and SEPA. It requires Commerce to develop model middle housing ordinances, a process cities use to seek state approval of required local actions. Commerce will also create guidance to assist cities on what to include in a parking study as well as general technical assistance. The bill includes several provisions amending SEPA, including a “safe harbor” clause for local governments that eliminate SEPA appeals for nonproject actions by local governments. The bill also creates a SEPA categorical exemption for amending development regulations to remove parking requirements from development proposed to fill in a UGA (RCW 43.21C.450).

Implementation Notes: Local governments will implement the bill.

Clean Energy Siting, and Transmission Planning (HB 1216)

Engrossed Second Substitute House Bill 1216 adds a new section to SEPA 43.21C.535 Clean energy projects—Nonproject environmental impact statements. This addition supports timely and effective siting and permitting for new clean energy projects while protecting the environment, overburdened communities, and Tribal rights and cultural resources. The bill establishes an Interagency Clean Energy Siting Coordinating Council, co-led by Ecology and Commerce, to consider and implement actions to improve permitting clean energy projects and provide an annual legislative report with recommendations.

solar panels and wind turbines in field.

HB 1216 establishes an optional coordinated clean energy permitting process led by Ecology for clean energy projects not using the Energy Facility Site Evaluation Council (EFSEC) process. The process includes timelines and requirements for environmental review and local and state permitting. Applicants would provide funds to conduct this process. The process must include Tribal consultation and engagement with overburdened communities.

The bill directs us to develop three programmatic EISs for solar, onshore wind, and green hydrogen facilities by June 30, 2025.

Implementation notes: The environmental assessments are underway.

Light Pollution (HB 1173)

Engrossed Substitute House Bill 1173 requires utility-scale wind energy facilities to install light mitigation systems that turn off aviation hazard lights when there are no planes nearby. The bill adds a new exemption to SEPA for projects to implement light mitigation projects in RCW 43.21C.540.

Facilities must use technologies approved by the Federal Aviation Administration. The bill applies to all new facilities. Existing facilities must seek to install light mitigation systems by Jan. 1, 2028, or upon the completion of repowering. Facilities have two years to install systems after getting approval.

The bill authorizes us to enforce the bill. Any penalties would be subject to appeals to the Pollution Control Hearings Board.

Implementation notes: We will reach out to facilities to ensure they are aware of the bill’s light mitigation requirements. While we aren't directed to update SEPA rules, we are authorized to adopt rules to reflect future changes adopted by the FAA.

Electrical Transmission Facility Siting (HB 5165)

Engrossed Substitute House Bill 5165 updates planning and permitting requirements for high-voltage electric transmission line projects and adds two new sections to SEPA in RCW 43.21C.405 and RCW 43.21C.408. One directs EFSEC to prepare a non-project EIS for transmission facilities and the other requires lead agencies to incorporate the EFSEC nonproject EIS in their environmental review.

Engrossed Substitute House Bill 5165 updates planning and permitting requirements for high-voltage electric transmission line projects. The updates attempt to help the state’s electricity transmission systems:

improve long-term efficiency
increase capacity to match renewable electricity generation and electricity demand
promote resilience against climate change impacts

The first new section requires EFSEC to prepare nonproject EIS’s for electrical transmission facilities with a nominal voltage of 230 kV or greater. Like other EIS’s, the bill requires disclosure and evaluation of probable environmental impacts and identification of mitigation measures. It also lists a handful of specific impacts that EIS’s must consider and requires each EIS to include a map showing probable significant adverse impacts in relation to the area evaluated.

The second section added to SEPA authorizes lead agencies conducting project-level environmental reviews of electrical transmission facilities of 230 kV or greater to consider nonproject EIS’s prepared under HB 5165 Sec. 6. The bill requires any project-level review of a proposed facility begin with a review of the applicable nonproject EIS to determine if any potential impacts will occur that the nonproject EIS does not consider. If the nonproject EIS recommendations address all significant adverse impacts, project-level impacts are considered mitigated. If additional significant adverse impacts would occur, the lead agency must complete an addendum or supplemental EIS to disclose and analyze these impacts, as well as identify mitigation measures to address the impacts.

Implementation notes: No rulemaking at Ecology will result from these changes.

Additional Housing Units in Existing Buildings (HB 1042)

Engrossed Substitute House Bill 1042 includes one amendment to SEPA in RCW 43.21C.450. The attempts to increase housing units in existing buildings by streamlining permitting and planning requirements for those types of development. The only change to SEPA amends nonproject actions under RCW 43.21C.450 to categorically exempt amendments to numerous types of local development regulations that govern development of existing buildings. Examples of these types of regulations include but are not limited to those that provide increased protections for critical areas and vegetation retention on shorelines, as well as protections against increased impervious surface area. In addition, the bill categorically exempts amendments to local building, energy, electrical, and other technical codes that ensure consistency with minimum state standards.

Implementation notes: Implementation will take place at the local government level. No rulemaking at Ecology will result from these changes.

Accessory Dwelling Unit Construction (HB 1337)

Engrossed Substitute House Bill 1337 attempts to expand housing options by streamlining the planning and permitting process for construction of accessory dwelling units. The only change to SEPA is an amendment to RCW 43.21C.495 adding a subsection that prohibits judicial or administrative appeals under SEPA of nonproject actions that are consistent with the accessory dwelling unit requirements in Sections 3 and 4 of HB 1337. These nonproject actions can include adoption of ordinances and development regulations, as well as amendments to comprehensive plans or subarea plans.