ADU rules in Spokane Valley

A detached backyard ADU is allowed outright, with no hearing and no discretionary review. The permitted use matrix marks 'Dwelling, accessory units' with an 'S' in R-1, R-2, R-3 and R-4 and in the MU, CMU, NC, RC and IMU zones, and SVMC 19.60.040(D) defines 'S' as allowed subject to the supplemental regulations of Chapter 19.65 SVMC, which for ADUs simply send the applicant back to Chapter 19.40 SVMC. Only one ADU is allowed per lot, attached or detached, so a detached unit consumes the lot's single allowance. An existing detached accessory structure such as a garage may be converted into a detached ADU provided every standard is met, including the setbacks. Two gaps are worth knowing: ADUs are not allowed at all in the MFR zone even though single-family dwellings are permitted there, and no ADU may be placed on a lot that already holds a duplex, a multifamily dwelling or an accessory apartment inside the principal structure.

Attached and internal ADUs run through the same permitted use matrix row and the same Type I administrative permit as detached ones; the SVMC defines an accessory dwelling unit as 'a freestanding detached structure or an attached part of a structure' and Chapter 19.40 SVMC sets one shared set of standards. There is no minimum house size and no lot-size gate for an attached unit. Two rules bite specifically on attached and internal conversions: the entrance must be on the side or rear of the structure, or otherwise unobtrusive when viewed from the front of the street, and only one entrance may sit on the facade of the primary dwelling; and the 50 percent size cap has no exception for converting existing basement or attic space, so a small house yields a very small internal unit. Because only one ADU is allowed per lot, an attached unit rules out a detached one on the same property.

The 50 percent rule is the binding constraint on almost every lot: a 1,400 sq ft house supports at most a 700 sq ft ADU, and a 1,000 sq ft house at most 500 sq ft. The footprint test in SVMC 19.40.030(B)(4) is far more generous and rarely governs, and because it reads 'whichever is greater' it overrides the tighter general accessory structure footprint rule of SVMC 19.65.130(A)(1) under the conflict clause in SVMC 19.40.020(A). Note that 'habitable square footage' is not defined anywhere in the SVMC, including Appendix A, so how the base figure is measured is a staff interpretation. Chapter 19.40 SVMC sets no separate ADU height limit, so the underlying zone's 35 ft dwelling height in Table 19.70-1 applies, and the unit still counts inside the zone's lot coverage cap of 30 percent in R-1, 50 percent in R-2 and R-3 and 60 percent in R-4. The two-bedroom cap in SVMC 19.40.030(B)(5) is a hard limit regardless of size.

Spokane Valley still enforces a full, ongoing owner occupancy requirement, one of the last in the Spokane area. The titleholder must occupy either the primary dwelling or the ADU as their permanent residence for six months or more of each calendar year and may at no time receive rent for the owner-occupied unit, and the application must include a letter from the owner affirming that one legal titleholder lives in one of the units. The obligation does not end at approval: before occupancy is issued, a deed restriction is recorded with the Spokane County Auditor noting the presence of the ADU, the owner occupancy requirement and the other maintenance standards, and approval may be revoked if the unit falls out of compliance. The city's application form adds a notarized affidavit in which the owner certifies a 50 percent or greater interest in the property and continued occupancy of one of the two units, and warns that a buyer who intends to keep renting the ADU must file a new Certification of Owner Occupancy within one year of transfer. An owner may cancel an ADU's registration by filing a letter with the county auditor.

SVMC 19.40.030(A)(3) requires one off-street parking space for the ADU in addition to the parking required for the primary dwelling unit, and Table 22.50-1 confirms both halves: 'Dwelling, accessory units, 1 per dwelling unit' and 'Dwelling, one- and two-family, townhouse, 2 per dwelling unit.' The space must be paved with asphalt or Portland cement, although grasscrete, paver blocks or an equivalent hard surface may be used for residential driveways and parking areas. The 25 percent reduction for sites within half a mile of a frequent transit route in SVMC 22.50.020(A)(9) applies only to nonresidential projects, so proximity to a transit line buys an ADU nothing; the only relief is the discretionary reduction of up to 25 percent that the city manager or designee may grant under SVMC 22.50.020(A)(7) on a written request demonstrating site conditions that prevent compliance. The city's ADU application site plan asks the applicant to mark the two existing required stalls and the one proposed paved stall.

Purely administrative. Table 17.80-1 classifies 'Accessory dwelling units' under Chapter 19.40 SVMC as a Type I application, and SVMC 17.80.020(A) defines Type I procedures as those that 'apply to permits and decisions issued administratively.' There is no public hearing, no neighbor notice and no discretionary approval criteria. The applicant files the city's Accessory Dwelling Unit application with a labeled floor plan, a site plan showing parcel dimensions, all existing and proposed structures, the ADU entry and the required parking stalls, and a description of the exterior design, plus a notarized affidavit of ownership and occupancy; the Planning Division signs the decision block and staff records the deed restriction with the Spokane County Auditor. Building permits are handled separately under SVMC Title 24 and are themselves Type I when not subject to SEPA. The only ADU flavor that needs a hearing is the industrial accessory dwelling unit of SVMC 19.40.040, a separate use in the IMU and I zones that requires a conditional use permit.

Chapter 19.40 SVMC sets no minimum lease term, no rent limit and no tenant restrictions, so a conventional long-term tenancy in the non-owner-occupied unit is unrestricted. What the code does forbid is renting out both units: SVMC 19.40.030(D)(1) requires the titleholder to live in one of them and bars rent on that unit. Home businesses are prohibited in the ADU entirely. On short stays, the phrase 'short-term rental' does not appear anywhere in the Spokane Valley Municipal Code (a full-text search of the code returned no match), so there is no registration, permit, cap or primary-residence test of the kind Spokane city adopted; short-stay lodging in a residential zone instead runs through the separate 'Bed and breakfast' use, permitted in R-1 through R-4 and MFR and defined as a single-family dwelling providing accommodations to paying guests, which is the house rather than the ADU. Lodging businesses owe the transient occupancy tax of Chapter 3.20 SVMC and, inside the tourism promotion area, the lodging charge of Chapter 3.21 SVMC. Separately, SVMC 5.05.010(C)(1) counts 'owning, renting, leasing, maintaining, or having the right to use, or using ... real property permanently or temporarily located in the City' as engaging in business, SVMC 5.05.020 requires anyone engaging in business to hold a city business license registration, and the exemptions in SVMC 5.05.030 do not carve out residential landlords. The code is silent on selling an ADU separately or as a condominium.