Salt Lake City vs Seattle: ADU, STR & Home Business Rules Compared (2026)
Compare ADU owner-occupancy and parking rules, short-term rental licensing, and home business rules between Salt Lake City, UT and Seattle, WA. Washington's statewide ADU preemption law drives the biggest ADU differences; Salt Lake City's short-term rental rules are not independently verified in this corpus.
Side-by-Side Comparison
Salt Lake City vs Seattle
| Salt Lake CityUT | SeattleWA | |
|---|---|---|
| ADUs Allowed? | Yes — Salt Lake City allows and regulates ADUs to promote housing stock and choice (Salt Lake City Code §21A.40.200) | Yes — Washington HB 1337 requires cities to allow at least two ADUs on lots zoned for single-family homes within an urban growth area (Washington HB 1337, RCW 36.70A.681(1)(c)) |
| Owner Occupancy Required? | Yes, ongoing — the property owner must reside on the property, with limited exceptions for duplexes/multi-family/non-residential principal uses, bona fide temporary absences of 3 years or less, or medical-facility placement (Salt Lake City Code §21A.40.200(C)) | No — Washington state law bars cities and counties from requiring the owner of a lot with an ADU to reside in or occupy the ADU or another housing unit on the same lot (Washington HB 1337, RCW 36.70A.681(1)(b)) |
| Parking Required? | Yes — one parking stall is required for the ADU, unless the property is in a zoning district with no minimum parking requirement, already has an extra accessible stall, or is near transit or a designated bicycle route (Salt Lake City Code §21A.40.200(G)(1)) | No — no off-street motor vehicle parking is required for an ADU (Seattle Municipal Code 23.42.022(I)) |
| STR Allowed? | Not independently verified — Salt Lake City's short-term rental licensing framework is referenced in the corpus but the underlying source cache is empty; see official source for Salt Lake City's current STR rules (Salt Lake City Code, STR licensing; slc.gov/planning) | Yes — short-term rental uses are permitted in any structure established as a dwelling unit (Seattle Municipal Code 23.42.060(A)) |
| Registration Required? | Not independently verified — Salt Lake City's short-term rental registration requirement is not confirmed against a primary source in this corpus; see official source before assuming a registration obligation (Salt Lake City Code, STR licensing; slc.gov/planning) | Yes — all operators of short-term rental uses must hold a valid short-term rental operator's license issued by the Department of Finance and Administrative Services (Seattle Municipal Code 23.42.060(C)(2)) |
| Registration Type | Not independently verified — a 'Short-Term Rental License' label appears in Salt Lake City's cached notes but is not confirmed against a primary source; see official source for the current registration type (Salt Lake City Code, STR licensing; slc.gov/planning) | Short-term rental operator's license (Seattle Municipal Code 23.42.060(C)(2)) |
| Home Business Allowed? | Yes — all home occupations not specifically listed as prohibited may be permitted, subject to compliance with the code's standards (Salt Lake City Code §21A.36.030(B)) | Yes — a home occupation of a resident is permitted outright in all zones as an accessory use to a permitted residential use (Seattle Municipal Code 23.42.050) |
| City Permit Required? | Yes — a license is required before engaging in a home occupation, obtained under Title 5, Chapter 5.02 of the city code (Salt Lake City Code §21A.36.030(E)) | No — a qualifying home occupation is permitted outright with no separate permit (Seattle Municipal Code 23.42.050) |
Key Differences
Salt Lake City and Seattle both allow ADUs, but their owner-occupancy and parking rules point in opposite directions. Salt Lake City requires ongoing owner-occupancy of the property (with limited exceptions for duplexes, multi-family uses, temporary absences, or medical-facility placement) and one on-site parking stall unless a transit, bicycle-route, or no-minimum-parking exception applies (Salt Lake City Code §21A.40.200). Seattle, operating under Washington's statewide ADU-preemption law (HB 1337), cannot require owner-occupancy for an ADU and cannot require any off-street parking for it at all (RCW 36.70A.681, Seattle Municipal Code 23.42.022(I)). Short-term rental comparison is one-sided here: Seattle's STR framework is fully verified — a short-term rental operator's license is required from the Department of Finance and Administrative Services (Seattle Municipal Code 23.42.060) — while Salt Lake City's STR posture is not independently verified in this corpus; the underlying source cache is empty, so see official source before relying on any Salt Lake City STR detail. Home business rules also diverge: Salt Lake City requires a license under Title 5, Chapter 5.02 before operating a home occupation (Salt Lake City Code §21A.36.030(E)), while Seattle permits a qualifying home occupation outright with no separate permit (Seattle Municipal Code 23.42.050).
Cost Comparison
Salt Lake City's ADU permit fees typically run $1,500–$6,000, with a 4–8 week review timeline (potentially faster for internal ADUs under Utah's ministerial-approval mandate). Seattle does not publish a fixed ADU permit fee range in the city's cached fee schedule, but pre-approved standard DADU plans from Seattle Department of Construction and Inspections can reduce review time, and school district impact fees of roughly $3,700–$7,400 per new unit may apply. Both figures are drawn from each city's cached fee/process notes and should be confirmed directly with Salt Lake City Building Services or Seattle Department of Construction and Inspections before budgeting.
Our Verdict
Seattle offers substantially more legal certainty and flexibility for ADU builders thanks to Washington's statewide preemption — no owner-occupancy requirement and no parking mandate at all. Salt Lake City's ADU rules (ongoing owner-occupancy, one required parking stall) make more sense for an owner adding housing for family rather than an investor seeking maximum flexibility. On short-term rentals, Seattle's rules are confirmed and require a city-issued operator's license, while Salt Lake City's STR posture cannot be confirmed from this corpus and should be checked directly with the city. For home businesses, Seattle's by-right approach is the lighter-touch option compared to Salt Lake City's license requirement.
Explore Each City
Frequently Asked Questions
Does Salt Lake City require owner-occupancy for an ADU?
Yes — the property owner must reside on the property on an ongoing basis, with limited exceptions for duplexes, multi-family or non-residential principal uses, bona fide temporary absences of three years or less, or medical-facility placement (Salt Lake City Code §21A.40.200(C)). Seattle, under Washington's statewide ADU law, cannot impose an owner-occupancy requirement (RCW 36.70A.681(1)(b)).
Does Seattle require parking for an ADU?
No — no off-street motor vehicle parking is required for an ADU in Seattle (Seattle Municipal Code 23.42.022(I)). Salt Lake City requires one parking stall unless the property qualifies for a transit, bicycle-route, or no-minimum-parking exception (Salt Lake City Code §21A.40.200(G)(1)).
Can I confirm Salt Lake City's short-term rental rules from this comparison?
Not fully — Salt Lake City's STR licensing framework is referenced in city planning materials, but the source cache backing this comparison is empty, so the details are not independently verified here; check with Salt Lake City Planning directly before relying on any STR rule. Seattle's STR framework is confirmed: a short-term rental operator's license from the Department of Finance and Administrative Services is required (Seattle Municipal Code 23.42.060(C)(2)).
Do I need a permit to run a home business in Seattle?
No, in most cases. A home occupation of a resident is permitted outright in all zones as an accessory use to a permitted residential use, with no separate permit required (Seattle Municipal Code 23.42.050). Salt Lake City requires a license under Title 5, Chapter 5.02 of its code before engaging in a home occupation (Salt Lake City Code §21A.36.030(E)).
Source: PropertyZoned Editorial Research. Last verified July 15, 2026.