Complete 2026 cost breakdown: construction, permits, financing, and expected rental ROI.
Calculate your Frisco ADU cost →Building an ADU in Frisco costs between $135,000-$270,000 for new construction, with per-square-foot costs averaging $155-$285. These figures include design, permitting, site preparation, and construction. The most affordable option is a garage conversion at $65,000-$150,000, while prefab/modular ADUs fall in between at $95,000-$205,000.
| Cost Category | Estimated Range |
|---|---|
| Architectural Plans | $3,000 – $15,000 |
| Permits & Fees | Frisco publishes a Permit Fee Schedule on its Residential Permits page, but the document is served behind a bot check and could not be read — Confirm current building permit and plan review amounts with Frisco Plans & Permits (972-292-5301) |
| Impact Fees | Confirm with Frisco Development Services (972-292-5301) — no ADU-specific impact fee schedule was found in a city source |
| 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. Get up to 5 free quotes from ADU builders serving Frisco — no obligation.
Get Frisco builder quotes →Permit fees in Frisco are Frisco publishes a Permit Fee Schedule on its Residential Permits page, but the document is served behind a bot check and could not be read — Confirm current building permit and plan review amounts with Frisco Plans & Permits (972-292-5301). The review timeline is Confirm with Frisco Plans & Permits (972-292-5301) — no published review timeline for a Garage Apartment or Guest House was found in a city source, with plan check: Standard residential plan review through Frisco's electronic permit portal. Budget for the facade rule: the exterior of an accessory structure must be built of the same exterior material as the main building and must meet or exceed §4.07.09 Exterior Construction of Main Buildings, with fiber cement siding allowed to satisfy the masonry requirement only on a structure of 200 sq ft or less in a single-family or two-family district (Frisco Zoning Ordinance §4.06.05). Confirm review timing with Frisco Plans & Permits (972-292-5301). Impact fees are Confirm with Frisco Development Services (972-292-5301) — no ADU-specific impact fee schedule was found in a city source. Pre-approved plans: No city pre-approved ADU plan library was found — Confirm with Frisco Development Services (972-292-5301).
| 1-Bedroom Rent | $1,300-$1,750/month |
| 2-Bedroom Rent | $1,700-$2,350/month |
| Annual Rental Income (est.) | $18,300/year |
| Payback Period (est.) | 11.1 years |
| Short-Term Rental | Allowed, but only with a permit. Frisco's short-term rental ordinance names your unit explicitly: an STR is a dwelling "including a single-family dwelling, garage apartment, guest house or a unit in a multi-unit building" rented for less than 30 consecutive days (Frisco Code of Ordinances §18-461). "No short-term rental shall operate within the city without a current, valid short-term rental permit," and every individual unit with cooking, sleeping and bathing facilities needs its own separate permit (§18-462, Ordinance 2021-08-52 adopted 8/17/21). The owner-occupancy condition in Zoning Ordinance §4.06.03(C)(2) still applies on top |
| Overall ROI Estimate | 5-8% annual return |
A typical ADU in Frisco generates approximately $18,300 per year in rental income based on average 1-bedroom rents. At an average construction cost of $202,500, the estimated payback period is 11.1 years — before accounting for the resale value the ADU adds, which an appraiser determines from comparable sales in Frisco 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 Frisco: $65,000-$150,000.
2. Prefab/modular ADUs offer predictable pricing and faster timelines. Average: $95,000-$205,000.
3. Pre-approved plans — Frisco does not offer a pre-approved/standard ADU plan program yet, so budget for custom architectural plans (typically $3,000-$15,000). 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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