ADU Cost in Utah (2026): Complete Pricing & Permit Guide
May 13, 2026
In plain English
An ADU (accessory dwelling unit) is a smaller second home on your property — a basement apartment, garage conversion, or backyard cottage. With Utah's new laws making approval easier, 2026 is the best year ever to build one.
Expect to invest $80,000 to $300,000+ depending on type, size, and finish level.
The 3 ADU types at a glance
| Type | Typical cost | Time | Best for |
|---|---|---|---|
| Internal (basement) | $80k – $160k | 3–5 months | Lowest cost, fastest |
| Attached (addition) | $150k – $280k | 5–8 months | More privacy, kitchen separation |
| Detached (backyard) | $200k – $400k+ | 7–12 months | Maximum privacy & rental value |
2026 reality: Utah's HB 82 and SB 174 require most cities to allow ADUs by-right on single-family lots. Permits that took 12 months in 2022 now close in 6–10 weeks.
Cost breakdown by type
Internal ADU (basement conversion)
| Item | Cost |
|---|---|
| Egress windows | $4k – $8k |
| Second kitchen | $18k – $40k |
| Bathroom | $14k – $28k |
| Separate entrance | $5k – $12k |
| HVAC zoning | $4k – $9k |
| Soundproofing floor | $3k – $7k |
| Permits & soft costs | $3k – $8k |
| Total | $80k – $160k |
Detached ADU (backyard cottage)
| Item | Cost |
|---|---|
| Site work & foundation | $25k – $55k |
| Framing & shell | $45k – $90k |
| Mechanical (HVAC/plumbing/electrical) | $30k – $55k |
| Interior finishes | $40k – $90k |
| Utility connections | $15k – $40k |
| Permits, design, soft costs | $15k – $35k |
| Total | $200k – $400k+ |
What changed with Utah's ADU laws
| Law | What it does |
|---|---|
| HB 82 (2021) | Most cities must allow internal ADUs by-right |
| SB 174 (2024) | Streamlined detached ADU approval, capped impact fees |
| HB 306 (2025) | Removed owner-occupancy requirements in many jurisdictions |
Cities still imposing extra rules: Park City, Holladay, and parts of Cottonwood Heights have historic district overlays. Always check your specific lot.
ROI: what an ADU is actually worth
| Use | Monthly value | Annual ROI |
|---|---|---|
| Long-term rental (Salt Lake) | $1,400 – $2,400 | 8 – 12% |
| Long-term rental (Park City) | $2,500 – $4,500 | 9 – 14% |
| Short-term/Airbnb (where allowed) | $3,000 – $7,000 | 12 – 22% |
| Multigenerational use | Saves $25k+/yr | Plus appreciation |
Resale impact: a permitted ADU typically adds $100k–$250k+ to home value in Utah's metro markets.
Permit timeline (typical 2026)
| Phase | Internal ADU | Detached ADU |
|---|---|---|
| Design | 3–6 weeks | 6–12 weeks |
| Permit review | 4–8 weeks | 6–12 weeks |
| Construction | 12–20 weeks | 24–40 weeks |
| Final inspection | 1–2 weeks | 2–3 weeks |
Financing options
| Option | Best for | Notes |
|---|---|---|
| HELOC | Existing equity | Variable rate, flexible |
| Cash-out refi | Locking low rate | Resets your mortgage |
| Construction loan | New detached ADU | Higher interest during build |
| Renovation loan (FHA 203k) | First-time investors | Lower down payment |
FAQ
Do I need an architect?
For detached ADUs, yes — Utah code requires stamped plans. Internal ADUs often only need a designer.
Can I rent it as Airbnb?
Depends on your city. Salt Lake City restricts short-term rentals heavily. Park City requires specific permits. Always verify before building.
Will it raise my property taxes?
Yes, typically by 15–30% of the ADU's added value. Often offset 4–10x by rental income.
How long do detached ADUs take?
Plan on 8–12 months from contract to certificate of occupancy.
Ready to build your ADU?
Get a free ADU feasibility study from Alpha Wolf →
We'll review your lot, your city's rules, and give you a real budget — not a fantasy quote.