Grays Harbor County, WA Accessory Structures: ADU Rules (2026)
ADU rules in Grays Harbor County, WA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Use type
- Conditional use, board of adjustment approval
- Occupant limit
- Family member only (blood, marriage or law)
- G-5 parcel size
- Must be under 10 acres
- Duration
- Fixed expiration or annual renewal set by board
- Governing section
- Grays Harbor County Code § 17.24.030(F)
Summary
Unincorporated Grays Harbor County does not zone for a standard accessory dwelling unit; instead it allows a temporary second dwelling for a family caregiver as a conditional use. County Code § 17.24.030(F) lets the board of adjustment approve one on any G-5 parcel under ten acres, restricted to a member of the property owner's family and subject to removal once the arrangement ends.
F.On any legal parcel which is less than ten acres, a second temporary dwelling unit may be authorized provided that the following conditions are met:(1)The accessory unit is for use by a member of the family of the occupants of the principal residence on the property. For the purposes of this section, "member of the family" means related by blood, marriage or law;(2)No division of the property is authorized;(3)The unit shall be removed or converted to a conforming use when the use authorized by the permit is discontinued;(4)The parcel shall comply with the minimum lot requirements of the health department for each unit;(5)The board of adjustment shall establish either a final expiration date or annual renewal by the administrator upon showing by the applicant that the approved use is continuing;
Full Breakdown
Rather than a conventional accessory dwelling unit ordinance, the county's zoning title handles a second home on one lot as a conditional second temporary dwelling unit, and § 17.24.030(F) spells out the conditions in the G-5 General Development Five District: the parcel must be under ten acres, the added unit can only be used by a member of the family of the occupants of the principal residence, defined in the section as someone related by blood, marriage or law, no division of the property is allowed, and the unit must be removed or converted to a conforming use once the permitted use is discontinued.
The parcel also has to meet the health department's minimum lot requirements for two units on one septic and water system, and the board of adjustment can set either a fixed expiration date or require an annual renewal showing the arrangement is still active. Nearly identical language authorizes the same use in the A-1 Agricultural district at § 17.12.030(F), the A-2 district at § 17.16.030(E), and the Lake Quinault district at § 17.42.030(A)(2), which caps eligible parcels at under four acres and adds that the unit must meet county potable water and sewage requirements.
None of these sections create a true by-right ADU; every one requires board of adjustment approval and ties the unit to a specific family relationship rather than to the lot itself.
Violations & Fines
Adding a second dwelling without board of adjustment approval under § 17.24.030(F) or the matching sections in the A-1, A-2 and Lake Quinault districts, renting it to someone outside the family, subdividing the parcel to create a separate lot for it, or keeping it in place after the caregiving arrangement or permit expires, is a zoning violation subject to Chapter 8.40 code enforcement and can require removal of the unit.
Frequently Asked Questions
Can I put a second, smaller home on my property for a family member in unincorporated Grays Harbor County?
Can I rent out the second dwelling to a tenant instead of housing family?
Does this second-dwelling rule apply outside the G-5 district?
Sources & Official References
Other rules in Grays Harbor County
How Grays Harbor County compares: Easiest Cities to Build an ADU·Compare Grays Harbor County to another location·View the Washington accessory structures overview
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