Building permits, zoning and land rules in Yakima County, Washington

Yakima County requires a permit before residential construction and other work regulated by the International Codes begins in its unincorporated jurisdiction¹. Work exempt from a building permit may still need zoning, utility, electrical, plumbing or mechanical approval¹. Yakima County reviews plans against current building codes and state and local regulations; ask Building & Fire Safety which code editions apply to your application¹². All permitted work must remain exposed for inspection until approved, and final inspection and approval are required before occupancy or use; we could not confirm a separate certificate requirement for every home¹³. An owner-builder can qualify for an exemption from contractor registration when working on their own property, except when the work is for sale, demolition or lease; project permits still apply^1,9. Do not assume a barn or farm structure is exempt from county review because the available agriculture provision concerns contractor registration⁹.

Yakima County Building & Fire Safety handles applications, plan review and inspections for new construction, alterations, grading, changes of use, relocated structures, and modular or manufactured-home placement¹². Reach the division at (509) 574-2300 or buildinginfo@co.yakima.wa.us; Accela Citizen Access supports the county's online application process¹². Project Coordinators route applications to the necessary reviewing divisions¹⁴. Building permit fees typically depend on square footage, construction type and occupancy; the county announced a 3.1 percent increase and an energy-code permit fee effective April 1, 2026^15,16. Inside Yakima, Toppenish and Selah, city offices handle building permits; Yakima Health District remains the on-site sewage authority^3,17,18,19.

Yakima County administers Title 19 zoning and reviews subdivision applications in unincorporated land within its land-use jurisdiction^2,11. Minimum lot size for land divisions and lot-line adjustments is district-specific; wastewater, access and other requirements can increase the area needed^6,10. Ask Planning for the parcel's district, setbacks, coverage and height limits^6,20. Title 19 sets no square-foot minimum dwelling size, but manufactured homes need siting review^10,21. ADUs are allowed conditionally; ask Planning to confirm the parcel's ADU limit and shared-water requirements before designing a separate dwelling^20,22,23.

Yakima, Sunnyside, Grandview, Toppenish and Selah administer their own zoning^{17,19,24,25,26}. Union Gap, Zillah, Mabton, Tieton and Harrah also administer their own zoning^{27,28,29,30,31}. Yakima Health District still handles on-site sewage review; Tieton also requires a public-works written permit for private sewage systems^3,32.

Yakima Health District administers on-site sewage permitting, review and inspection throughout Yakima County^3,33. A new or replacement on-site system needs a site-and-soil evaluation, design review, application fee, approved design and permit before installation begins^3,4. The Health District performs the final inspection before a new system is covered, then can sign off on the residence's Certificate of Occupancy³. If an available public sewer is within 200 feet, or the parcel is in a city utility service area, sewer connection may be required instead of septic³. Off-grid homes in Yakima County still need Health District approval for septic where sewer is unavailable and septic is allowed³. Only about 21.1 percent of county soils are rated without severe limits for a conventional drain field, so settle wastewater feasibility before locating the house³⁴. Reach Environmental Health at (509) 249-6508 or YHD.HelpDesk@co.yakima.wa.us³³.

Outside an approved campground or RV park, unincorporated Yakima County allows one self-contained RV on privately owned land for temporary use of no more than 30 days when the county's ownership, equipment and no-addition conditions are met⁶. Overnight occupancy by two or more camping units must meet campground or RV-park requirements⁶. While a permanent dwelling is being built on the same lot, an RV may instead qualify for up to 3 years with both a temporary-use permit and an active residential building permit, and it must be removed within 30 days after the home is occupied⁷. A tiny home used as a dwelling is a building regulated by the state building code; a park-model RV under 400 square feet is treated as temporary recreational equipment unless the stated manufactured-home-community exception applies⁸. Local zoning and installation approval still control where either type may go⁸.

1. Ask Planning to identify the zoning district, allowed dwelling type and district-specific lot and setback standards^6,20.
2. Ask the Yakima Health District whether sewer connection is required or septic is allowed, then complete the site-and-soil evaluation before fixing the house location^3,4.
3. Resolve access through the Road Approach Permit process for a connection to county right-of-way, or document legal access to an approved county-road location if the parcel lacks frontage³⁵.
4. Ask Building & Fire Safety for a Flood Hazard Determination if the parcel is FEMA-mapped; a structure within the 100-year floodplain needs a Flood Hazard Development Permit, with Flood Development review during plan review and elevation documentation before building-permit issuance^1,5,12.
5. Submit plans to Building & Fire Safety, whose Project Coordinators route the application to required divisions^12,14.
6. Keep permitted work exposed for required inspections and obtain final approval before occupancy or use¹³.

Before buying land in unincorporated Yakima County, ask Planning about district-specific lot area, setbacks, coverage and height, especially if you intend to divide the parcel^2,6,10,20. A county-road approach is reviewed case by case, and the listed Road Approach Permit fee is $275³⁵. We could not confirm a complete private-well permit rule, so ask Environmental Health and the applicable water provider before closing³³. FEMA-mapped projects need flood review and elevation documentation; new or replacement manufactured homes are prohibited in floodways⁵. Median property taxes are about $2,299 per year at an effective rate near 0.8 percent³⁴.