To complete and submit the Washington SEPA environmental checklist, get the current form from the city, county, or state agency reviewing your project, answer every environmental question in Parts A and B with specific numbers and attached technical studies, have the property owner or authorized representative sign it, and file it with your permit application so the lead agency can issue a threshold determination. The checklist itself is the tool the State Environmental Policy Act (RCW 43.21C) uses to decide whether your proposal needs conditions, clears review, or triggers a full Environmental Impact Statement.
Confirm You Actually Need a Checklist
Not every project triggers SEPA review. WAC 197-11-800 exempts categories of minor new construction that fall below set thresholds, and if your proposal fits inside those thresholds you can skip the checklist entirely. The default state thresholds include up to four single-family homes or four multifamily units; commercial or office buildings up to 4,000 square feet of gross floor area with parking for 20 or fewer cars; agricultural structures up to 10,000 square feet used only by the property owner for farming (feed lots are excluded); and fill or excavation up to 100 cubic yards over the total lifetime of the project.1Washington State Legislature. WAC 197-11-800
Other exempt activities include installing commercial signs, constructing bus stops and loading zones, and minor road work like pavement marking, turn restrictions, and guard rails. Local jurisdictions can raise or lower these flexible thresholds, so confirm with your lead agency before assuming you are exempt. If you are not exempt, WAC 197-11-315 requires a threshold determination, and the checklist is how the agency gets there. In practice, private applicants fill it out themselves.2Washington State Legislature. WAC 197-11-315
Get the Right Version of the Form
The Washington Department of Ecology publishes downloadable SEPA templates, but lead agencies frequently use customized versions with jurisdiction-specific questions. Get the checklist directly from the local or state agency reviewing your proposal rather than relying on the generic state template.3Washington State Department of Ecology. SEPA Document Templates Most city and county planning departments post their version online or hand out copies at the permit counter.
How the Checklist Is Organized
The form prescribed by WAC 197-11-960 has four parts: background information about the project (Part A), environmental elements (Part B), non-project actions (Part C, used only for policy or regulatory proposals), and supplemental information (Part D). For a typical development project, Part B is where you spend the most time. Each element asks you to describe existing conditions, explain how your proposal changes them, and identify measures to reduce impacts.4Washington State Legislature. WAC 197-11-960
Earth, Air, and Water
The Earth section asks about terrain, soil types, slope steepness, erosion risk, and soil stability. You describe planned filling, excavation, or grading, give the total quantities involved, and identify your fill source. You also estimate the percentage of the site that will be covered by impervious surfaces after construction.
Air quality questions cover emissions during construction and operation, including dust, vehicle exhaust, industrial odors, and wood smoke, plus any off-site emission sources that could affect the project.
The Water section is one of the longest. You identify streams, lakes, ponds, wetlands, or saltwater bodies on or within 200 feet of the site, estimate fill or dredge material going into them, describe any surface water withdrawals, note whether the site sits in a 100-year floodplain, and explain any planned waste discharge. Groundwater questions cover well usage, approximate withdrawal volumes, and whether stormwater will be directed into the ground. You also describe your stormwater management approach and water quality measures.
Plants, Animals, and Energy
For plants, you identify existing vegetation types and coverage, flag any species on the Washington State Department of Natural Resources’ heritage program list, and describe proposed landscaping or mitigation plantings. The animals section asks about species that use the site for habitat, nesting, or migration, with particular attention to threatened or endangered species.
Energy and natural resources questions address the amount of energy your project will need during construction and operation, the source of that energy, and whether the project will affect renewable resources like solar access or wind patterns. Mineral or resource extraction impacts go here.
Environmental Health, Land Use, and Public Services
Environmental health covers toxic or hazardous chemicals stored, used, or produced on site; noise during and after construction; and any risk of explosion or release of harmful substances. If the project sits on or near a known contaminated site, disclose that here along with any planned cleanup measures.
Land and shoreline use questions ask you to describe current use of the site and surrounding area, identify applicable zoning designations, and explain how the proposal fits within the local comprehensive plan and any shoreline master program. Transportation questions cover expected traffic generation, new parking spaces, and effects on nearby roads and transit service. The public services and utilities section asks whether the project will increase demand for fire protection, police, schools, water supply, sewer, stormwater, or other infrastructure.
One shortcut is worth knowing. Under WAC 197-11-315, a lead agency can identify checklist questions already covered by local ordinances, development regulations, or land use plans. When that happens, the agency explains how the project satisfies those local requirements and you can skip a full narrative for those questions, though you still have the option to answer them.
Supporting Documents and Signatures
Written answers carry more weight when backed by supporting materials. Include detailed site plans, topographic maps, drainage diagrams, and any technical studies relevant to your answers: geotechnical reports, traffic studies, wetland delineations, critical areas assessments. Visual and technical aids give reviewers spatial context and reduce back-and-forth requests for clarification.
The property owner or an authorized representative signs the completed checklist. If you are not the property owner, attach documentation showing your authority to act on their behalf. A complete package with checklist, signatures, and supporting materials reduces administrative delays from missing information.
Submitting the Checklist
File the completed checklist with the lead agency responsible for your project’s environmental review. For most private development proposals, that is the city or county where the project is located. Submission methods vary. Some jurisdictions accept online submissions through a permit portal; others require paper copies delivered in person or by mail. Check with your lead agency for current requirements and SEPA review fees, which vary by jurisdiction and project complexity.
The Department of Ecology recommends meeting with your lead agency before submitting, to discuss the project, applicable regulations, and the expected timeline. A pre-application conference can identify potential issues before formal review begins.5Washington State Department of Ecology. Basic Overview of State Environmental Policy Act
What Happens After You Submit
The lead agency’s responsible official reviews the checklist and issues a threshold determination. Under WAC 197-11-310, every non-exempt proposal gets one of these outcomes:6Washington State Legislature. WAC 197-11-310
- A Determination of Nonsignificance (DNS) concludes the project is unlikely to cause significant adverse environmental impacts. A DNS may include a 14-day public comment period, though this is not always required.
- A Mitigated Determination of Nonsignificance (MDNS) identifies potential impacts but concludes they can be reduced to a nonsignificant level through specific conditions or project changes. An MDNS always includes a public comment period.
- A Determination of Significance (DS) concludes the project may cause significant adverse impacts and triggers a requirement to prepare a full Environmental Impact Statement before the project can move forward.
A DNS lets your project proceed without conditions; an MDNS lets it proceed with mitigation conditions attached. A DS adds public scoping, a draft EIS, a comment period, and a final EIS, which can add months or years to your timeline.
Counties and cities operating under the Growth Management Act can use a streamlined optional DNS process under WAC 197-11-355. The lead agency combines the SEPA comment period with the notice of application for the underlying permit, states that it expects to issue a DNS, warns that this may be the only opportunity to comment on environmental impacts, and lists any mitigation conditions being considered. After reviewing comments, the agency issues the DNS or MDNS with no additional comment period, adds one if warranted, or switches to a DS if serious concerns surface.7Washington State Legislature. WAC 197-11-355
Appealing a Determination
WAC 197-11-680 governs administrative appeals of threshold determinations. For project actions in counties and cities subject to integrated project review, an appeal of a SEPA determination issued alongside the project decision must be filed within 14 days after notice that the decision has been made and is appealable. When the appeal is of a DNS that required public comment, the deadline extends by an additional seven days, for 21 days total. Appeals are consolidated with any hearing on the underlying permit and heard by a single hearing officer or body, which in most jurisdictions is the local hearing examiner. Filing fees vary by jurisdiction.8Washington State Legislature. WAC 197-11-680
Habits That Prevent Delays
Vague or incomplete answers are the most common reason agencies request additional information, which stalls your permit timeline. A few practical habits help:
- Answer every question. “Not applicable” is a valid response where it genuinely fits, but a blank field signals you may have overlooked the issue. If a section does not apply, say so briefly and explain why.
- Be specific with numbers. Instead of “some grading will occur,” write “approximately 500 cubic yards of cut and 300 cubic yards of fill.” Reviewers can evaluate measurable quantities; they cannot evaluate generalities.
- Identify mitigation early. If you know your project will produce stormwater runoff or remove trees, describe your management plan in the checklist rather than waiting for the agency to flag it. Proactive mitigation makes an MDNS far more likely than a DS.
- Attach technical reports. Geotechnical assessments, traffic impact analyses, and wetland delineations done by qualified professionals carry more weight than self-reported descriptions. If your site has steep slopes, critical areas, or sits near a water body, invest in the study before submitting.
- Use the pre-application meeting. Agencies will often tell you upfront which sections will get the closest scrutiny for your type of project, and that conversation saves revision cycles later.