Utah's statewide internal-ADU law, in plain terms
Utah's HB 82, codified at Utah Code 10-9a-530, made internal accessory dwelling units a permitted use statewide in most single-family zones as of October 1, 2021 — meaning a basement apartment no longer needs a conditional-use hearing in most places. An internal ADU is a second living unit created within an existing single-family home's footprint, rented for 30 days or longer. The state removed the blanket owner-occupancy mandate, but it expressly let cities keep one — so Highland, Alpine, Lehi, Draper, Sandy, and others can still require the owner to live on-site, and many do. State law also caps it at one ADU per home and lets cities require registration or a rental license, charge for inspections, and add parking rules. Translation: the right to build is statewide, but the conditions are local. Always confirm the specifics with your city before you frame a wall.
A legal bedroom needs real egress
Every sleeping room in a Utah basement apartment must have its own emergency escape and rescue opening — this is the rule people fail most. Under the IRC as adopted by Utah, an egress window needs a minimum net clear opening of 5.7 square feet, at least 24 inches of clear height and 20 inches of clear width, with the sill no higher than 44 inches off the floor. If the window well is deeper than 44 inches, you'll need a permanently affixed ladder or steps. A bedroom without conforming egress is not a legal bedroom, no matter how nice the finish. Cutting a new egress opening through the foundation is structural concrete work — Wasatch Finish does not do that. We coordinate or refer that to the appropriate licensed trade, then handle the interior finish around the new well once it's in.
Ceiling height, kitchen, and the entrance
A legal basement apartment in Utah needs at least 7-foot ceilings in habitable rooms (IRC R305.1), with beams, ducts, and girders allowed to drop to 6 feet 4 inches. Habitable rooms generally must be at least 70 square feet, and a bedroom at least 7 feet in any direction. The unit needs a kitchen — typically a sink, cooking appliance, and refrigerator space — to count as a true dwelling rather than a bedroom suite. On entry, the law allows either a shared interior entrance or a separate exterior one; an internal ADU can share the home's existing entry, which is why basements work so well as IADUs. A new separate exterior entrance, where a city wants one, is exterior/structural work handled by the right trade — Wasatch Finish builds the interior.
Smoke alarms, CO, radon, and parking
A legal basement apartment in Utah needs hardwired, interconnected smoke alarms and carbon-monoxide detection per fire code, plus proper fire separation between the unit and the rest of the home. Given Utah's radon problem — roughly half of tested Utah homes register above the EPA's 4 pCi/L action level, and basements are the most affected space — testing and, if needed, mitigation is a smart step before you finish, even when it isn't strictly required for permitting. Parking is set locally: many Wasatch Front cities require one dedicated off-street space for the ADU on top of the home's existing parking, so check your city's number before you assume the driveway covers it. These are the details that turn a finished basement into a legal, rentable unit rather than just extra living space.
Where Wasatch Finish fits — and what gets referred out
Wasatch Finish handles the interior finish of a basement apartment: framing the interior walls within the existing footprint, insulation, drywall, paint, trim, interior doors, flooring, and the finish work on a kitchenette or bathroom — all non-structural, all scoped under $50,000 to match our Utah DOPL R101 license. A modest finished basement on the Wasatch Front runs about $40–$90 per square foot by finish level, and an added basement bath typically falls around $8,000–$18,000. What we don't do, and won't claim to: cutting a new egress window well into the foundation, building a separate exterior entrance, moving or adding an electrical sub-panel, or relocating plumbing stacks — those are structural and MEP scopes referred to the appropriate licensed trades. Permits and the ADU registration are filed by the owner or general contractor. We finish the space; the city signs off on the unit.
Bottom line
A basement apartment is legal in Utah when it's a permitted internal ADU (HB 82 / Code 10-9a-530) with real egress, 7-foot ceilings, a kitchen, smoke/CO alarms, and your city's registration and parking met — Wasatch Finish does the non-structural interior finish; egress cut-ins, exterior entrances, and panel/plumbing work are referred out. Confirm specifics with your city.
Questions
Is a basement apartment legal in Utah?
Yes — a basement apartment is legal in Utah when it's a permitted internal accessory dwelling unit (IADU) under HB 82 / Utah Code 10-9a-530 and the finished space meets code. Since October 1, 2021, internal ADUs are a permitted use statewide in most single-family zones, so no conditional-use hearing is usually needed. You still must register with your city, pass inspection, and meet egress, ceiling-height, kitchen, and alarm requirements. Confirm local rules with your city first.
Does the owner have to live in the home to rent a basement apartment in Utah?
Not under state law, but possibly under your city's rules. Utah's HB 82 removed the statewide owner-occupancy mandate for internal ADUs, but it expressly let cities keep one — and many Wasatch Front cities do require the owner to live on-site. That makes owner-occupancy the single biggest local variable. Check your specific city's ADU ordinance before counting on renting a basement unit while living elsewhere, because the answer genuinely differs from city to city.
What does a legal basement bedroom need in Utah?
A legal basement bedroom in Utah needs a conforming egress window, a 7-foot ceiling, and interconnected smoke and CO alarms. The egress opening must give at least 5.7 square feet of net clear opening, 24 inches of clear height, 20 inches of clear width, and a sill no higher than 44 inches. The room needs at least 70 square feet and 7 feet in any direction. Without conforming egress, the room cannot be legally counted or rented as a bedroom.
Can Wasatch Finish build a basement apartment?
Wasatch Finish builds the interior finish of a basement apartment — framing within the existing footprint, insulation, drywall, paint, trim, doors, flooring, and kitchenette or bath finish — all non-structural and under $50,000 per our Utah DOPL R101 license. We do not cut new egress wells into the foundation, add exterior entrances, move sub-panels, or relocate plumbing stacks; those structural and MEP scopes are referred to licensed trades. The owner or GC files permits and the ADU registration.
How much does it cost to finish a basement apartment in Utah?
Finishing a basement apartment in Utah generally runs about $40–$90 per square foot depending on finish level, with an added bathroom typically around $8,000–$18,000. The interior finish — framing, drywall, paint, trim, flooring, and kitchenette finish — fits within a non-structural, under-$50,000 scope. Separate egress cut-ins, exterior entrances, and panel or plumbing relocation are priced and handled by the appropriate trades. These are planning ranges; your real number follows an on-site visit.