Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Salt Lake City ADU cost →Building an ADU in Salt Lake City costs between $180,000-$350,000 for new construction, with per-square-foot costs averaging $300-$350. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $120,000-$200,000, while prefab/modular ADUs fall in between at $100,000-$180,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | About $3,000-$5,000 in building-permit plus plan-review fees for a $150,000-$300,000 ADU: permit $1,425.97 plus $8 per $1,000 over $100,000 (Code 18.32.035), plan review 65% of that (FY2027 Consolidated Fee Schedule, amended 6/16/2026). Trade permits and a $35-per-unit rental licence are extra. |
| Impact Fees | Charged on every new dwelling unit (ADU Handbook v2.2). FY2027 city impact fees per residential unit: single-family rate $5,832 (park $5,173, transportation $429, fire $171, police $59) or multi-family rate $3,550 (park $3,078, transportation $242, fire $171, police $59); Building Services (801-535-7712) assigns the ADU's category. A $545 sewer and $1,871 water connection fee apply only if the ADU gets its own service; storm water $374 per 1/4 acre where it applies (CFS FY2027; Code 18.98, 17.44.060, 17.16.040). |
| Site Prep & Foundation | $10,000 – $35,000 |
| Framing & Structure | $15,000 – $45,000 |
| Plumbing | $8,000 – $20,000 |
| Electrical | $5,000 – $15,000 |
| HVAC | $3,000 – $8,000 |
| Interior Finishes | $15,000 – $40,000 |
Quotes for the same ADU commonly vary 20–40% between builders. We pass your request to up to 5 local builders serving Salt Lake City, where we have them — free, no obligation.
Get Salt Lake City builder quotes →Permit fees in Salt Lake City are About $3,000-$5,000 in building-permit plus plan-review fees for a $150,000-$300,000 ADU: permit $1,425.97 plus $8 per $1,000 over $100,000 (Code 18.32.035), plan review 65% of that (FY2027 Consolidated Fee Schedule, amended 6/16/2026). Trade permits and a $35-per-unit rental licence are extra.. The review timeline is Review times are not published. The Handbook shows building-code, fire, Public Utilities, Engineering and Transportation reviews before the permit, then covenant, owner-occupancy and zoning-certificate steps before occupancy; ask Building Services (801-535-7968) for the current residential queue., with plan check: 65% of the building-permit fee (Code 18.32.035, CFS FY2027). Expedited review costs twice the standard plan-review fee (18.20.050); review of an identical plan set is 30% (Utah HB 368, 2025). Review duration is not published.. Impact fees are Charged on every new dwelling unit (ADU Handbook v2.2). FY2027 city impact fees per residential unit: single-family rate $5,832 (park $5,173, transportation $429, fire $171, police $59) or multi-family rate $3,550 (park $3,078, transportation $242, fire $171, police $59); Building Services (801-535-7712) assigns the ADU's category. A $545 sewer and $1,871 water connection fee apply only if the ADU gets its own service; storm water $374 per 1/4 acre where it applies (CFS FY2027; Code 18.98, 17.44.060, 17.16.040).. Pre-approved plans: Five pre-approved standard plans on the Building Services ADU page (checked Sept 2026): a 650 sq ft 1-bedroom, a 775 sq ft 2-bedroom, an 800 sq ft 2-bedroom, a detached-garage conversion and a second-storey garage conversion, all drawn by private firms. A site review is still required for the permit and all fees still apply. The Planning Division's ADU Handbook (v2.2) is the zoning guide..
| 1-Bedroom Rent | $1,300-$1,650/month |
| 2-Bedroom Rent | $1,600-$2,000/month |
| Annual Rental Income (est.) | $17,700/year |
| Payback Period (est.) | 15.0 years |
| Short-Term Rental | No. An ADU may not be rented as a short-term rental (21A.40.200.Q.1) and the recorded restrictive covenant bars short-term rental of both the ADU and the main house (P.3). |
| Overall ROI Estimate | Roughly 5-10% gross yield: a 1-bedroom at the HUD FY2026 Fair Market Rent ($1,456/mo, about $17,500/yr) against a $180,000-$350,000 build, before vacancy, tax, insurance and upkeep - 10-20 years to recover the build cost. |
A typical ADU in Salt Lake City generates approximately $17,700 per year in rental income based on average 1-bedroom rents. At an average construction cost of $265,000, the estimated payback period is 15.0 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Salt Lake City and varies by market (often less than build cost).
1. Garage conversions save 40-60% vs new construction since the shell already exists. Average cost in Salt Lake City: $120,000-$200,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $100,000-$180,000.
3. Pre-approved plans — available in Salt Lake City, which can save $3,000-$10,000 in design costs and 2-3 months in review time. See which cities offer pre-approved ADU plans.
4. State grants — California's CalHFA ADU grant (up to $40K) is currently paused; check calhfa.ca.gov/adu for status and your state for active programs.
5. Get multiple bids — ADU contractor pricing varies 20-40% for the same project. We recommend getting at least 3 quotes.
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