Jurisdiction
ADUs in Spokane Valley
These rules apply to lots inside the City of Spokane Valley, a separate jurisdiction from the City of Spokane and unincorporated Spokane County. Because Spokane Valley is in an urban growth area, Washington HB 1337 governs ADUs here and sets the baseline.
State law sets the Spokane Valley baseline
Spokane Valley is a Growth Management Act city inside an urban growth area, so Washington's HB 1337 governs ADUs here. Under state law, Spokane Valley must allow at least two ADUs per lot, may not require owner-occupancy (except where the unit is used as a short-term rental), may not cap ADU size below 1,000 square feet, and may not cap ADU height below 24 feet. State law also caps an ADU impact fee at 50 percent of what the principal unit would pay, which matters here because Spokane Valley charges transportation impact fees in three subareas under Ordinance 22-005: the South Barker Corridor, Mirabeau, and North Pines Road. The city publishes no ADU rate and no ADU exemption, so ask the permit center whether a fee applies to your parcel.
Spokane Valley's local municipal code is still being updated to match state law, and some published materials may still reference older limits such as a lower height cap, a percentage-of-primary size cap, or an owner-occupancy deed restriction. Where the local code is stricter than HB 1337, state law controls for parcels inside the urban growth area.
Confirm how the current rules apply to your property with Spokane Valley Community Development, and check whether your lot can support an ADU.
The permit process in Spokane Valley
ADU permitting runs through the Spokane Valley permit center, which reviews zoning and building requirements and issues permits. A call to Spokane Valley Community Development confirms the exact local numbers and the status of the city's HB 1337 code update. Our homeowner permit guide explains what to expect.
Spokane Valley ADU questions
- Does Spokane Valley have its own ADU rules?
- Yes, but as a Growth Management Act city inside an urban growth area, Spokane Valley is governed by Washington HB 1337, which sets the baseline. The city municipal code (SVMC 19.40.030) is still being updated to match state law. Confirm the exact local numbers with Spokane Valley Community Development.
- Is owner occupancy required for a Spokane Valley ADU?
- No. HB 1337 prohibits owner-occupancy requirements inside an urban growth area, except where the unit is used as a short-term rental. Older SVMC language requiring owner-occupancy predates HB 1337 and is superseded.
- Does Spokane Valley charge impact fees on an ADU?
- It may. Spokane Valley adopted transportation impact fees for three subareas by Ordinance 22-005: the South Barker Corridor, the Mirabeau subarea, and the North Pines Road subarea. Neither the city ADU page nor the city impact fee page publishes an ADU rate or an ADU exemption, so ask the permit center whether a fee applies to your parcel. Where one does apply, HB 1337 caps an ADU impact fee at 50 percent of what the principal unit would pay (RCW 36.70A.681). Other permit and connection fees still apply, set by the city master fee schedule.
References and primary sources
Regulatory and fee specifics on this page are cited to the current primary sources below. Confirm any figure against its source for your specific parcel before you rely on it.
- City of Spokane Valley ADU page (spokanevalleywa.gov) City ADU information and permit center.
- Spokane Valley Municipal Code 19.40.030 (ecode360.com) Accessory dwelling unit standards.
- City of Spokane Valley residential building permits (spokanevalleywa.gov) Master fee schedule (Resolution 25-013).
- City of Spokane Valley transportation impact fees (spokanevalleywa.gov) The three subareas adopted by Ordinance 22-005. No ADU rate or exemption is published.
- RCW 36.70A.681 (app.leg.wa.gov) HB 1337 requirements that preempt conflicting local rules.
Related
What it costs, and what happens after you send it
- What does an ADU cost in Spokane Valley?
- detached new-build $110,000 to $260,000, garage conversion $50,000 to $120,000, prefab or modular installed $80,000 to $180,000. Add roughly $3,000 to $5,000 in permit, plan review and impact fees, which is an estimate from one source rather than a published fee schedule, so confirm it with your permitting jurisdiction.
- How solid are those numbers?
- Treat them as planning ranges, not prices. They come from two third-party estimator sites, ADU Zoning and ADU Wizard, both read in full on 2026-08-17, neither of them a government publication. The two land in nearly the same place on total project cost, which is why totals are shown here. They differ by roughly a factor of two on cost per square foot, so a per-square-foot rate is not a reliable way to budget an ADU here and none is quoted.
- How fast will someone get back to me?
- Your request goes to an independent local ADU builder, usually within about an hour during the day. The builder then contacts you to look at the property and price the project on their own schedule.
- What types are covered?
- Detached ADUs, attached ADUs, garage conversions and basement junior ADUs. See every type.
Only a builder standing on your lot can price your actual project.
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