Basement apartments and ADUs planned around permits, privacy, kitchens, laundry, and egress.
A basement apartment can add usable space and, when it is legal to rent, potential monthly income. It can also make room for aging parents, adult children saving for a home, or guests who need privacy. The details matter because legal ADUs have code, parking, entry, and permit requirements.
Utah has become more ADU-friendly in recent years. HB 82, passed in 2021, requires most municipalities to allow internal ADUs in residential zones, but each city still has its own rules.
Utah Basement Finishing designs and constructs legal, permitted basement apartments, accessory dwelling units (ADUs), and mother-in-law suites throughout Salt Lake, Utah, Davis, and Weber counties. We handle design, permits, construction, and all the regulatory navigation so you end up with a unit that’s both livable and legal.
If ADUs are part of the plan, bring them up before the general basement layout is drawn. A basement apartment changes almost every major decision: entry location, kitchen plumbing, bathroom placement, bedroom egress, laundry, sound control, fire separation, parking, electrical load, and city approval.
A smart first pass is:
Similar to a full apartment but designed for family rather than tenants:
We check ceiling height, separate entrance options, plumbing access, electrical panel capacity, parking, and zoning rules. Not every basement can become a legal apartment, and we will tell you upfront if yours is a poor fit.
We create a full apartment floor plan with kitchen, bathroom, bedroom(s), living area, laundry, and storage. Plans include fire separation details, egress windows, electrical load calculations, and HVAC design. We submit to the building department and manage the review process.
Full buildout: framing, fire-rated assemblies, plumbing, electrical, HVAC, insulation, drywall, flooring, cabinets, fixtures, and exterior entry work. Timeline: 8-14 weeks depending on scope.
Multiple inspections throughout construction (framing, fire separation, rough plumbing, rough electrical, insulation, final). After the final inspection, you receive a certificate of occupancy, the legal document that allows you to rent the unit.
| ADU Configuration | Cost Range |
|---|---|
| Studio apartment (no separate bedroom) | $40,000–$60,000 |
| 1-bedroom apartment | $50,000–$80,000 |
| 2-bedroom apartment | $65,000–$100,000 |
| Mother-in-law suite (connected, kitchenette) | $35,000–$60,000 |
| Mother-in-law suite (full kitchen, ADA features) | $50,000–$80,000 |
Major cost components:
At Utah’s current rental rates:
We see basement ADU and mother-in-law suite questions most often in growing Salt Lake and Utah County markets where homeowners want flexibility without moving: Salt Lake City, South Jordan, Herriman, Riverton, West Jordan, and Lehi.
Rules can change by city, so do not design the apartment from a generic checklist. We verify feasibility before treating the basement as rental-ready.
Is a basement apartment legal in Utah? In most cases, yes. Utah’s HB 82 (2021) requires cities to allow internal ADUs (including basement apartments) in residential zones. However, specific requirements vary by municipality, lot size minimums, parking requirements, owner-occupancy rules, and impact fees differ from city to city. We research your specific situation before starting.
Do I need a separate entrance for a basement apartment? For a legally rentable ADU, most municipalities require a separate entrance that doesn’t pass through the main dwelling. For a mother-in-law suite occupied by family, a shared entrance is typically acceptable. We’ll clarify requirements for your city.
What’s the difference between an ADU and a mother-in-law suite? Functionally, they’re similar. Legally, an ADU is a separate dwelling unit with its own entrance, kitchen, and bathroom that can be rented to non-family members. A mother-in-law suite is typically an internal living space designed for family that may share an entrance with the main home. ADUs require more stringent fire separation, separate utilities (in some jurisdictions), and permits.
Do I have to live in the home to rent a basement apartment? Many Utah municipalities require owner-occupancy, meaning the homeowner must live in either the main house or the ADU. Some cities have relaxed this requirement. We verify the specific rules for your property.
Will building a basement apartment increase my property taxes? Potentially. Adding a legal ADU increases your home’s assessed value, which may increase property taxes. However, the rental income typically far exceeds any tax increase. Consult with your tax advisor for specifics.
Can I use my basement apartment for Airbnb/short-term rental? It depends on your city’s short-term rental regulations. Some Utah cities allow short-term rentals in ADUs with a business license; others restrict ADUs to long-term rentals only (30+ days). Salt Lake City, for example, has specific short-term rental licensing requirements. We’ll point you in the right direction for your jurisdiction.
Start generating rental income from your basement. Call 801-515-3473 for a free ADU feasibility estimate.
Utah Basement Finishing, 369 E 900 S #235, Salt Lake City, UT 84111 | Mon–Sat 8am–6pm