Building permits, zoning and septic rules in Grays Harbor County, Washington

Grays Harbor County requires a building permit to erect, move, add to or structurally alter a building or structure in unincorporated areas; building approval must conform to county zoning¹. The Building Division enforces the 2021 International Building, Residential, Fire, Mechanical, Fuel Gas and Existing Building codes, plus the Washington State Energy Code and Uniform Plumbing Code, with state and local amendments⁹. County inspections check that permitted work is safe and code-compliant, so ask Planning & Building which inspections the project needs¹⁰. Washington's energy code also requires permitted work to remain visible and accessible for inspection and requires final approval before occupancy¹¹. Washington's owner-builder exemption concerns contractor registration; it does not waive building permits or other construction requirements and does not cover work performed to sell, demolish or lease the property^4,12. Inside McCleary, the city Building Official approves building permits before construction; septic remains with county Environmental Health^3,13.

Grays Harbor County's Planning & Building Division is at 100 W. Broadway Ave. #31, Montesano, WA 98563; call 360-249-5579 or email pbd@graysharbor.us¹⁴. County construction permitting begins with a required pre-application meeting requested through the online portal⁹. The published sequence is Site Plan Review, related permits or approvals, and then the building-permit application⁹. Site Plan Review can identify road access, addressing, septic, fire access, water availability or other approvals for the particular project⁹. Building-permit fees vary with project value, square footage and construction type, so ask a Permit Coordinator for an estimate before submitting¹⁵. Grays Harbor County water and sewer service reaches only select areas, so confirm service and water availability for the parcel⁸.

Grays Harbor County administers zoning, land-use standards and subdivision rules in unincorporated areas; incorporated cities and towns apply their own regulations². Ocean Shores, Montesano, Westport, Elma, McCleary and Oakville set their own zoning inside city limits; county Environmental Health still handles septic^{3,16,17,18,19,20,21}. Dividing land or developing mobile-home or RV parks in unincorporated Grays Harbor County requires county review unless an exemption applies; boundary-line adjustments and lot consolidations are exempt from subdivision requirements²². Minimum lot size depends on the district: Rural Residential needs at least 1 acre, R-1 Restricted Residential 15,000 square feet, R-2 General Residential 10,000 square feet for the first dwelling, and R-3 Resort Residential 7,200 square feet for a single-family home, each unless health regulations require a larger area for septic and water^23,24,25,26. In the A-1 Agricultural district, a use must sit on a parcel that was legally created before the ordinance or meets the 10-acre or fractional-section alternative²⁷. We could not confirm complete residential setback, coverage, height or minimum-home-size standards; ask Planning & Building for the parcel’s district requirements¹⁴.

Grays Harbor County Environmental Health administers on-site sewage-system design, installation and maintenance countywide³. Applications for new or modified systems must include a design and go through SmartGov; paper is accepted only for drawings³. Every system must be designed by a Washington-licensed on-site designer or professional engineer, and site preparation includes two test holes in the primary and reserve drainfield areas²⁸. Prepare the test holes for Environmental Health inspection: each must be 2 feet wide and 6 feet deep³. The published 2025 schedule lists a $1,000 new residential conventional-system permit and a $1,300 alternative-system permit, with fees adjusted each January; confirm the current amount before applying²⁹. Only 3.1% of county soils lack severe limits for a conventional drain field, so establish septic feasibility before treating a rural parcel as buildable⁷. The county does not require a septic inspection for a private-home sale, but a lender, government loan program or real-estate professional may request a pumper's report³.

Washington allows a tiny house on wheels of no more than 400 square feet when it is built to the state building code, but foundation, installation, location and local permits still depend on Planning & Building approval⁵. We could not confirm Grays Harbor County's rule for long-term occupancy of one RV or a tiny home on private land, so ask Planning & Building about the parcel and proposed use before relying on either as housing¹⁴. County RV-park review does not establish permission to live in an individual RV: park development requires subdivision review, and mobile-home parks have layout and setback requirements while RV parks require boundary buffering and landscaping²². A short-term rental in an eligible unincorporated zoning district generally needs a county STR permit, with an exception for rental use approved through a Conditional Use Permit or Planned Unit Development before March 22, 2022⁶. County STR permits require annual renewal at least 30 days before expiration; contact Planning & Building about additional requirements when buying a rental approved under a Conditional Use Permit⁶.

1. Request the required pre-application meeting through the county's online permitting portal⁹.
2. Submit Site Plan Review so the county can identify zoning and related approvals for the parcel⁹.
3. Secure the approvals the review identifies, which may include road access, addressing, septic, fire access and water availability⁹.
4. If septic is needed, hire a Washington-licensed on-site designer or professional engineer and prepare the test holes for Environmental Health²⁸.
5. Resolve access with the correct road authority. Fire-equipment-access and Public Works road-access reviews apply as needed; a new county-road approach requires county permission, while a state-highway connection requires written WSDOT permission^15,30,31.
6. Submit the building-permit application and plans after securing the required related approvals⁹.
7. Keep permitted work visible for required inspections and obtain final approval before occupancy¹¹.

Confirm septic feasibility first: only 3.1% of Grays Harbor County soils lack severe limits for a conventional drain field⁷. Ask Planning & Building to identify the parcel’s zoning district and applicable lot size, setbacks, height, coverage and allowed uses². Grays Harbor County regulates development in flood zones; ask Planning & Building which floodplain standards apply¹⁰. Washington requires a local floodplain development permit for work on floodplain property³². Verify road jurisdiction and whether Site Plan Review calls for access approval rather than assuming every parcel follows the same driveway process¹⁵. Confirm water and sewer availability because county utility service is limited to select areas⁸. Washington's domestic groundwater exemption allows up to 5,000 gallons per day per project without a water-right permit, but additional restrictions can apply; a notice to Ecology is required 72 hours before drilling and does not approve water use³³.