Enacted by the Washington Legislature in 1971, the State Environmental Policy Act – commonly called SEPA – helps state and local agencies in Washington identify possible environmental impacts that could result from governmental decisions such as:

  • Issuing permits for private projects such as an office building, grocery store, or apartment complex.
  • Constructing public facilities like a new school, highway, or water pipeline.
  • Adopting regulations, policies, or plans such as a county or city comprehensive plan, critical area ordinance, or state water quality regulation.

SEPA applies to all decisions made by state and local agencies including:

  • Washington state agencies
  • Cities
  • Counties
  • Ports
  • Special districts such as school and water districts

SEPA informs decisions

Everyday, state and local agencies in Washington use SEPA to evaluate proposed decisions. Information learned through the review process can be used to:

  • Change a proposal to reduce likely impacts.
  • Apply conditions to or deny a proposal when adverse environmental impacts are identified.

Some minor projects can be exempt

SEPA also gives local governments the option to allow some minor construction projects to be exempt from review, depending on their size and scale.

Lead agencies for specific proposals

Under SEPA, one government agency is usually identified as the lead agency for every proposal determined not to be exempt from review. The lead agency identifies and evaluates potential adverse environmental impacts of a proposal. In practice:

  • For most private projects, the lead agency is typically either the city or county where the project is located.
  • For public projects, the lead agency is normally the agency proposing the project.

This evaluation is documented and sent to the public and other agencies for their review and comment.

Environmental checklist key SEPA tool

Under SEPA, project proponents are usually asked to complete an environmental checklist. The checklist asks questions about the proposal and its potential impacts on the environment including:

  • Air
  • Animals
  • Earth
  • Energy
  • Environmental health
  • Land use
  • Plants
  • Public services
  • Transportation
  • Utilities
  • Water

After the checklist has been completed, the lead agency will review it and other information about the proposal. If more information is needed, the lead agency can ask the applicant to conduct further studies such as:

  • Traffic studies
  • Site studies to evaluate potential air quality, water quality, or wetlands impacts

When a proponent has gathered and submitted enough information about their proposal, the lead agency can:

  • Issue a determination of non-significance – also called a DNS – if it finds the proposal is unlikely to have a significant adverse environmental impact.
  • Require that a neutral third party prepare an environmental impact statement – or an EIS – if the information indicates the proposal is likely to have a significant adverse environmental impact.

An EIS needs to include:

  • An evaluation of alternatives to the proposal.
  • Measures that would reduce or eliminate likely environmental impacts.

Using SEPA in decision making

The DNS prepared by the lead agency or an EIS completed by a third party provides critical information to all agencies involved in the environmental review and approval process.

As agency decision-makers determine whether or not to issue a license or permit for a proposal, they carefully consider all the information in a DNS or EIS along with technical, economic, and other information.

SEPA gives state and local agencies the authority to require conditions to offset any identified adverse environmental impacts.

In rare cases, an agency can deny a proposal when an EIS shows a proposal is likely to have significance adverse environmental impacts that cannot be reduced to an acceptable level.

Other resources for reviewers

For questions or comments concerning SEPA, please e-mail sepahelp@ecy.wa.gov or call (360) 407-6922.

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