Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Buffalo ADU cost →Building an ADU in Buffalo costs between $110,000-$220,000 for new construction, with per-square-foot costs averaging $120-$250. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $55,000-$130,000, while prefab/modular ADUs fall in between at $80,000-$180,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | Building-permit fees are set on construction value; the current schedule was not retrievable online - confirm with Permit & Inspection Services. Zoning fees (OSP memo eff. July 1, 2025): area variance $150 (1-2 units), minor site plan $350, special use permit $350. |
| Impact Fees | None - the UDO contains no development impact fee; confirm any water or sewer connection charges with Buffalo Water. |
| 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 Buffalo, where we have them — free, no obligation.
Get Buffalo builder quotes →Permit fees in Buffalo are Building-permit fees are set on construction value; the current schedule was not retrievable online - confirm with Permit & Inspection Services. Zoning fees (OSP memo eff. July 1, 2025): area variance $150 (1-2 units), minor site plan $350, special use permit $350.. The review timeline is Not published - the city does not post plan-review times for residential permits; ask Permit & Inspection Services when you register the project., with plan check: Not published; part of the building-permit review by Permit & Inspection Services.. Impact fees are None - the UDO contains no development impact fee; confirm any water or sewer connection charges with Buffalo Water.. Pre-approved plans: None - Buffalo publishes no pre-approved ADU plan set (Sept 2026)..
| 1-Bedroom Rent | $1,000-$1,300/month |
| 2-Bedroom Rent | $1,150-$1,550/month |
| Annual Rental Income (est.) | $13,800/year |
| Payback Period (est.) | 12.0 years |
| Short-Term Rental | Not addressed by the ADU rules; confirm with Permit & Inspection Services |
| Overall ROI Estimate | Not estimated; HUD FY2026 SAFMR $970-$1,290/mo (1-BR) against a $110,000-$220,000 build |
A typical ADU in Buffalo generates approximately $13,800 per year in rental income based on average 1-bedroom rents. At an average construction cost of $165,000, the estimated payback period is 12.0 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Buffalo 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 Buffalo: $55,000-$130,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $80,000-$180,000.
3. Pre-approved plans — available in Buffalo, 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.
Tell us about your project and we'll pass it to ADU builders serving Buffalo. Free, no obligation — you choose who to work with. We don't have builders in every area yet; if nobody covers yours, we'll email you to say so.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Just browsing? Search ADU builders near you by ZIP code.