Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Roseville ADU cost →Building an ADU in Roseville costs between $170,000-$400,000 for new construction, with per-square-foot costs averaging $250-$500. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $90,000-$200,000, while prefab/modular ADUs fall in between at $170,000-$340,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | Per the city's Accessory Dwelling Units Fee Policy — confirm current amounts with Development Services at (916) 774-5332 |
| Impact Fees | Waived for ADUs 750 sq ft or less of interior livable space (state law); see the city ADU Fee Policy for larger units |
| 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 Roseville, where we have them — free, no obligation.
Get Roseville builder quotes →Permit fees in Roseville are Per the city's Accessory Dwelling Units Fee Policy — confirm current amounts with Development Services at (916) 774-5332. The review timeline is 60-day state-mandated review; deemed approved if the city misses the deadline (SB 543, Jan 2026), with plan check: Standard building plan check; preapproved master plans reduce review time — confirm timing with the Building Division. Impact fees are Waived for ADUs 750 sq ft or less of interior livable space (state law); see the city ADU Fee Policy for larger units. Pre-approved plans: Yes — Preapproved ADU Plans program per AB 1332 (master plans preapproved for site-specific permit submittal).
| 1-Bedroom Rent | $2,050-$2,350/month |
| 2-Bedroom Rent | $2,500-$2,900/month |
| Annual Rental Income (est.) | $26,400/year |
| Payback Period (est.) | 10.8 years |
| Short-Term Rental | No — state law requires ADU rentals to run longer than 30 days (Gov. Code 66323(e)). Roseville's short-term rental chapter (Ch. 4.25 as of July 2026: no STR permits for ADUs or JADUs) — confirm with Planning. |
| Overall ROI Estimate | 7-14% gross annual return |
A typical ADU in Roseville generates approximately $26,400 per year in rental income based on average 1-bedroom rents. At an average construction cost of $285,000, the estimated payback period is 10.8 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Roseville 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 Roseville: $90,000-$200,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $170,000-$340,000.
3. Pre-approved plans — available in Roseville, 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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