Basement apartments
The ApartmentAlready In Your House
Utah law treats a unit inside your home's existing footprint as an internal ADU — permitted in residential zones and exempt from impact fees. For most homes that means the basement.
What Utah law allows
Utah sets a statewide floor for internal accessory dwelling units, which means a city cannot simply ban them in residential zones. The rules are narrower than people expect in one direction and more generous in another: you have to live in the house, but you do not pay impact fees to add a unit inside it.
The relevant sections are Utah Code 10-21-303 for cities and 17-80-303 for counties, with the impact-fee exemption at 11-36a-202.
- Permitted use
- An internal ADU is a permitted use in any area zoned primarily for residential use, subject to local conditions.
- Owner-occupied
- It applies to a detached single-family home occupied as the primary residence of the owner of record.
- Inside the footprint
- The unit must sit within the footprint of the primary dwelling as it stood when the ADU was created. A finished basement is the textbook case.
- No impact fees
- Construction of an internal ADU is not subject to impact fees. Ordinary building permit fees still apply.
- Code still applies
- It must meet all applicable building, health and fire codes. This is the part that decides whether a given basement actually works.
What your city can still require
The state sets the floor. Your city fills in the rest, and two neighbouring cities can land somewhere genuinely different. These are the conditions the statute allows them to attach.
Parking
Off-street parking requirements are common, and on a narrow lot they occasionally decide the whole question.
Appearance standards
Cities may require the house to still read as a single-family home from the street.
Permitting or licensing
A separate registration or licence for the unit, on top of the building permit, is permitted.
No short-term rental
A city may prohibit using the unit as a short-term rental. If a nightly-rental income model is your plan, check this first.
Rental and occupancy rules
Some cities layer their own occupancy rules on top, and those vary most in university towns. Provo is the one to check carefully.
What decides whether your basement works
Ceiling height
The one constraint that cannot be designed around. If the finished height will not make code, no amount of clever layout fixes it, so we measure to the joists before anything else. Older Provo and Springville homes are where this most often ends the conversation.
Egress
A bedroom needs a compliant egress opening. In newer homes that often means enlarging an existing window well, which is exterior work — so it is both a permit item and, in an HOA neighbourhood, an approval item.
A second way out, and separation
A separate entrance, and the fire separation between the unit and the rest of the house, are what turn a finished basement into a dwelling in the eyes of the code. They are also the items most often skipped by unpermitted work.
Mechanical and metering
Heating, ventilation and how utilities are handled all shape both cost and how the unit lives day to day. Worth deciding early, because it moves walls.
Common questions
Is a basement apartment legal in Utah?
An internal accessory dwelling unit is a permitted use in areas zoned primarily for residential use, under Utah Code sections 10-21-303 for cities and 17-80-303 for counties. The main conditions are that the home is a detached single-family house, that you live in it as your primary residence, and that the unit sits within the existing footprint. Your city can still attach its own requirements, so confirm the specifics with them before you build.
Do I have to live in the house?
For an internal ADU, yes. The statute describes it as applying to a detached single-family home occupied as the primary residence of the owner of record. A basement apartment in a house you rent out entirely is a different thing legally, and your city may treat it very differently.
Will I pay impact fees on a basement apartment?
Utah Code section 11-36a-202 exempts construction of an internal ADU from impact fees. That is a meaningful saving and one of the clearer advantages of building inside the existing footprint rather than adding on. Building permit fees are separate and still apply.
What can my city still require?
Quite a lot. Cities may set a minimum lot size, impose appearance standards, require off-street parking, run their own permitting or licensing process, and prohibit using the unit as a short-term rental. Two neighbouring cities can land in genuinely different places, which is why we check with yours before drawing anything.
Does the basement need anything special to be legal living space?
Yes. It has to meet the applicable building, health and fire codes, and a bedroom needs a compliant egress opening. Ceiling height is the constraint that most often decides the question outright in older homes, because it cannot be designed around. We measure it on the first visit.
Can you handle the permitting?
Yes. We pull the permit under your address and coordinate inspections. You should never be in a position where work happens on your home without a permit that names it — that is one of the specific things the national remodeling associations tell homeowners to check.
Worth being clear about
This page is orientation, not legal advice. It summarises the statewide rules for internal ADUs as we understand them, last reviewed September 2026. Statutes change, and your city’s own requirements sit on top of them and vary considerably across Utah Valley.
Before you spend money on a design, confirm the specifics with your city’s planning department — or ask us and we will make the call with you. We would rather tell you early that your basement will not work than take a deposit and find out later.
Tell Us AboutYour Project
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- Service area
- Utah County · Salt Lake County · Summit County
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