Kitsap County

Permits for ADUs on parcels in unincorporated Kitsap County are issued by the Kitsap County Department of Community Development (DCD). DCD operates a combined permit intake for planning review (zoning / critical-areas conformance) and building review (International Residential Code / Washington State amendments). Incorporated cities inside Kitsap (Bainbridge Island, Bremerton, Port Orchard, Poulsbo) handle their own ADU permits through their own departments and are NOT covered by this unincorporated-permitting record.

Process overview: An ADU on an unincorporated Kitsap parcel is permitted as a combined planning/building permit. Typical workflow: pre-application review (optional, recommended for critical-areas parcels), submission of site plan and construction drawings, planning review for zoning and critical-areas conformance, building-code plan review, issuance, construction with inspections, and final certificate of occupancy. Critical-areas parcels (steep slopes, wetlands, marine shorelines, wellhead protection zones) add a critical-areas report and may add a SEPA threshold determination.

Impact fees: Kitsap County levies school, traffic, and park impact fees on new residential units pursuant to KCC Chapter 4.110 and the county's adopted impact-fee schedule. The exact fee amounts change annually and are published on the DCD website; an ADU constructed as a second unit on an existing lot is typically assessed at the applicable ADU rate rather than the full single-family rate. (schedule)

The Kitsap County Assessor maintains parcel-level assessment records for all real property in Kitsap County, including parcels within incorporated cities. ADU additions are assessed as improvements to the host parcel; Washington does not permit separate tax-parcel creation for an attached ADU, but a detached ADU sold as a condominium under RCW 36.70A.680 receives its own tax parcel upon condominiumization.

Assessment policy: ADU additions are captured on the next physical-inspection cycle or via self-reported improvement. Washington's Revaluation Cycle (RCW 84.41) requires annual revaluation with a physical inspection at least every six years; Kitsap revalues annually. There is no statewide ADU-specific exemption; local Multi-Family Property Tax Exemption (MFTE) programs under RCW 84.14 are city-level and do not generally apply to detached unincorporated-area ADUs.

Kitsap County administers critical-areas and shoreline overlays that cut across multiple jurisdictions and materially affect ADU siting. The county's critical-areas ordinance is in KCC Title 19 and covers wetlands, fish and wildlife habitat conservation areas, frequently flooded areas, geologically hazardous areas, and critical aquifer recharge areas. The county's Shoreline Master Program governs development within 200 feet of Puget Sound shorelines under the Shoreline Management Act (RCW 90.58).

• Kitsap County Critical Areas Ordinance — Regulates development within designated critical areas. An ADU proposed on or near a mapped critical area requires a critical-areas report prepared by a qualified professional and may require buffer averaging or reasonable-use authorization.
• Kitsap County Shoreline Master Program (SMP) — Applies to shorelines of statewide significance, shorelines of the state, and shorelands within 200 feet of the ordinary high-water mark on Puget Sound and other jurisdictional water bodies in Kitsap. An ADU within the shoreline jurisdiction requires a Shoreline Substantial Development Permit unless specifically exempt.
• FEMA Special Flood Hazard Areas (SFHA) — Kitsap participates in the National Flood Insurance Program and enforces FEMA-mapped SFHAs through the county floodplain-management ordinance. An ADU proposed in a Zone A, AE, or VE area faces elevation, venting, and anchoring requirements that materially change construction cost.
• Wildland-Urban Interface (WUI) / Wildland Fire Hazard — Washington adopted a statewide WUI code effective July 2023. Kitsap enforces WUI construction requirements on parcels mapped as moderate, high, or extreme wildland-fire hazard. ADUs on mapped WUI parcels require ignition-resistant construction measures that affect cladding, roofing, vent protection, and defensible space.
• Critical Aquifer Recharge Areas (CARA) — Kitsap relies substantially on groundwater; CARA overlays restrict certain uses and may require enhanced on-site sewage system design or connection to public sewer for a new ADU, depending on the underlying zone and CARA category.