ADU (accessory dwelling unit) Planning in Klickitat County, WA (2026)

For a Klickitat County ADU, first establish whether the property is in unincorporated county jurisdiction or inside Goldendale, White Salmon, or Bingen. Also identify any Columbia River Gorge National Scenic Area, shoreline, floodplain, or critical-area constraints. A mailing address alone is not enough to select the rules.

Check the adopted rule before choosing a model

The county is reviewing ADU changes in 2026. Its August 5 environmental-review notice describes proposed changes to size, distance from the main house, owner occupancy, rentals, and parking. An environmental determination is not an adopted zoning amendment or a permit approval.

Ask Planning to identify the adopted ADU ordinance and permit process that apply to your application. Older brochures and workshop drafts can differ, so don’t rely on the old brochure’s fee or estimated review time for a current project.

Questions that determine model fit

Before selecting a floor plan, confirm these items for the parcel:

• Whether the zoning allows an ADU and whether it can be detached.
• The permitted number of homes and whether an existing dwelling changes eligibility.
• The current floor-area and bedroom limits.
• How the separation from the main house is measured, plus property-line setbacks and height.
• Whether owner occupancy, rental restrictions, or a recorded covenant apply.
• The land-use review required before building approval, including any application deadline or expiration condition.

Get those answers from the rules in force. Don’t assume a proposed relaxation has taken effect. If the property is in a city, obtain that city’s requirements.

Water and wastewater come early

Collect the existing well or water-service records and the approved septic design. Ask Environmental Health and the water provider whether the additional dwelling can be served and what approvals or upgrades are required. Do not assume an existing well automatically supports a second home or that a new well is an available solution.

Show septic tanks, drainfields, replacement areas, water lines, easements, and the proposed foundation on the site plan. Utility feasibility can change both placement and budget.

Access, parking, and installation

Confirm whether the ADU must share the existing driveway, what parking is required, and whether road-approach or emergency-access improvements are needed. Wolf separately checks the delivery route, turning space, staging area, and trailer or crane setting options.

Factory construction does not remove the need for local foundation, placement, utility, and inspection approvals. Keep those costs separate from the home price when comparing options.

For Gorge and Mt. Adams delivery, snow, and how Klickitat compares with other mountain counties, see mountain cabins and ADUs in the Cascades.

Start with your property

Send the address or parcel number and intended use. Keep any survey, well records, septic approval, and earlier county correspondence available. We can start the property review and compare the current Wolf models with the requirements that apply.

Request a free Wolf property evaluation.

Planning information reviewed September 14, 2026. Confirm current adopted requirements and fees with the responsible permitting office before committing to a design.