State Environmental Policy Act. The State Environmental Policy Act (SEPA) establishes a review process for state and local governments to identify environmental impacts that may result from governmental decisions, such as the issuance of permits or the adoption of land use plans. The SEPA environmental review process involves a project proponent or the lead agency completing an environmental checklist to identify and evaluate probable environmental impacts. Government decisions that the SEPA checklist process identifies as having significant adverse environmental impacts must then undergo a more comprehensive environmental analysis in the form of an environmental impact statement (EIS). Under SEPA, certain nonproject actions are categorically exempt from threshold determinations and EISs in rule. Examples of categorical exemptions include various kinds of minor new construction and minor land use decisions.

 
State Environmental Policy Act?Categorical Exemptions?Housing Development.  All project actions that propose to develop one or more residential housing units within the incorporated areas in an urban growth area or middle housing within the unincorporated areas in an urban growth area and that meet certain criteria are categorically exempt from SEPA.

Before adopting the categorical exemption jurisdictions must satisfy the following criteria:

• the proposed development must be consistent with all development regulations implementing an applicable comprehensive plan under the Growth Management Act (GMA) adopted by the jurisdiction in which the development is proposed, with the exception of any development regulation inconsistent with applicable provisions of the GMA; and
• the city or county has prepared an environmental analysis that considers the proposed use or density and intensity of use in the area proposed for exemption and analyzes multimodal transportation impacts.

Before finalizing the environmental analysis the local government must provide a minimum of 60 days' notice to affected tribes, relevant state agencies, other jurisdictions that may be impacted, and the public and address any probable adverse impacts.

The environmental analysis must include documentation that the requirements for environmental analysis, protection, and mitigation for impacts to elements of the environment have been adequately addressed for the development exempted. The city or county must document its consultation with the Washington Department of Transportation on impacts to state-owned transportation facilities including consideration of whether mitigation is necessary for impacts to transportation facilities.  The categorical exemption is effective 30 days after the requirements of the environmental analysis are completed by a local government.

Until September 30, 2025, all project actions that propose to develop one or more residential housing or middle housing units within a city west of the crest of the Cascade Mountains with a population of 700,000 or more are categorically exempt from SEPA.  After September 30, 2025, project actions that propose to develop one or more residential housing or middle housing units within the city may utilize the categorical exemption in the manner provided for cities and counties generally.

All project actions that propose to develop one or more residential units within the incorporated areas in a Urban Growth Area must be connected to a sewer system to be categorically exempt from SEPA. 

 
A city or county must prepare an environmental analysis that considers the proposed density and intensity of use in the jurisdiction's comprehensive plan, rather than the area proposed for an exemption.  The environmental analysis must include sufficient subarea detail to identify the potential development ceiling and impacts to facilities. 

The city or county must document its consultation with the Department of Transportation (WSDOT) on impacts to state-owned transportation facilities and identify how impacts identified by WSDOT will be addressed through mitigation.  The city or county may address specific probably adverse impacts to state-owned transportation facilities by including them in concurrency programs and subdivision and dedication approval process.

Nothing in the environmental analysis grants a private party the right to seek judicial relief requiring compliance with the provisions related to this categorical exemption.