Everything homeowners ask about building an ADU in Frisco — answered with 2026 data.
Yes, ADUs are allowed in "A Garage Apartment or Guest House shall be allowed as an incidental use on the same lot or tract as the main dwelling unit" (Frisco Zoning Ordinance §4.06.03), in the residential districts the accessory-structure standards apply to — AG, RE, SF-16, SF-12.5, SF-10, SF-8.5, SF-7, OTR, PH, 2F, TH, MF-15, MF-19 and MH (§4.06.01). Frisco's Use Chart at Subsection 3.02 is published as a graphic rather than as searchable text in the online code, so the district-by-district permission could not be read directly — confirm your parcel's district with Frisco Development Services at 972-292-5301 in Frisco, TX. The maximum size for a detached ADU is No ADU-specific floor-area cap appears anywhere in Frisco's zoning ordinance — §4.06.03 sets location, permit, rental and setback standards for a Garage Apartment or Guest House but states no maximum size. What binds instead is the district's maximum lot coverage for all buildings: 45% in SF-7, SF-8.5 and SF-10, 40% in SF-12.5, 30% in SF-16, 20% in RE and 55% in OTR (Frisco Zoning Ordinance §2.06.04). Note also that a detached unit in Frisco is a Guest House, which §7.01.01 does not define as a dwelling unit — confirm with Frisco Development Services (972-292-5301) before designing a detached unit with a kitchen. Attached ADUs can be up to No size cap stated. A Garage Apartment must be built attached to a garage, either above it or on the same level. Frisco has an ADU-friendliness score of 5/10. Check our full Frisco ADU rules page for complete zoning details.
ADU construction in Frisco typically costs $135,000-$270,000. The cost per square foot averages $155-$285. Garage conversions are more affordable at $65,000-$150,000, while prefab ADUs cost $95,000-$205,000. Permit fees add 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) to your budget. See our detailed Frisco ADU cost guide.
Detached ADUs in Frisco can be up to No ADU-specific floor-area cap appears anywhere in Frisco's zoning ordinance — §4.06.03 sets location, permit, rental and setback standards for a Garage Apartment or Guest House but states no maximum size. What binds instead is the district's maximum lot coverage for all buildings: 45% in SF-7, SF-8.5 and SF-10, 40% in SF-12.5, 30% in SF-16, 20% in RE and 55% in OTR. Attached ADUs are limited to No size cap stated. A Garage Apartment must be built attached to a garage, either above it or on the same level. Junior ADUs (JADUs) have a cap of Not a category in Texas — Frisco's ordinance has no junior ADU designation. Maximum height is No height limit specific to a Garage Apartment or Guest House. The residential district maximum applies — 40 feet / 2.5 stories in AG, RE, all five SF districts, OTR, PH and 2F (Frisco Zoning Ordinance §2.06.04). The 8-foot figure that appears in Figure 4.06.04.1 is a condition for the reduced 3-foot rear setback on alley-backing lots, not a general accessory-structure height cap — confirm with Frisco Development Services (972-292-5301). You are allowed up to The ordinance states no numeric cap. §4.06.03 allows "a Garage Apartment or Guest House" as an incidental use on the lot, and §4.07.01 on a qualifying lot.
Rear setback: Same as the primary structure. Figure 4.06.04.1 gives the row "Guest House or Garage Apartment" setback note D — "Same as Primary Structure Setback" — front, side and rear, so it does not get the 3-foot rear setback ordinary accessory buildings on alley-backing lots may use (Frisco Zoning Ordinance §4.06.03(D), §4.06.04(G)). In practice that is 30 feet in AG, RE, SF-16, SF-12.5, SF-10, SF-8.5, SF-7 and 2F, and 8 feet (20 feet for a garage facing an alley) in OTR — Original Town Residential (§2.06.04). The figure is a graphic; confirm your number with Frisco Development Services (972-292-5301). Side setback: Same as the primary structure, with 15 feet required where the structure is adjacent to a side street (Figure 4.06.04.1, notes C and D). By district the primary side yard is 7 feet in SF-7 and SF-8.5, 10 feet in SF-10, 15 feet in SF-12.5 and SF-16, 20 feet in AG and 6 feet in OTR, with larger corner-lot side yards in each (Frisco Zoning Ordinance §2.06.04). No accessory structure may sit in the side yard setback between the front and rear yard setback lines (Figure 4.06.04.1, note 2). Front setback: Same as the primary structure (Figure 4.06.04.1, note D) — 25 feet in SF-7 and SF-8.5, 30 feet in SF-10 and SF-12.5, 40 feet in SF-16, RE and AG, and 20 feet plus a 5-foot utility easement in OTR (Frisco Zoning Ordinance §2.06.04). Separately, no accessory structure may project into the front yard beyond the face of the primary structure, porch excluded (Figure 4.06.04.1, note 3). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
No additional parking is required for a Garage Apartment or Guest House — neither use appears in Frisco's parking schedule at §4.04.08, which sends "Dwellings, single-family and two-family" to §4.04.02(E). That baseline requires a minimum of two enclosed garage parking spaces plus two paved spaces behind the front property line in RE, SF-16, SF-12.5, SF-10, SF-8.5, SF-7, OTR, PH, 2F and TH (Frisco Zoning Ordinance §4.04.02(E)). Confirm with Frisco Development Services (972-292-5301) before relying on the absence. Many cities and states have been relaxing ADU parking requirements in recent years. In California, no additional parking is required for ADUs near transit.
Required in order to rent. "A Garage Apartment or Guest House may be rented or offered for rent provided that the main dwelling unit is owner-occupied" (Frisco Zoning Ordinance §4.06.03(C)(2)). The unit also may not be sold separately from the entire property including the main dwelling (§4.06.03(C)(1)), and owner-occupancy is written into the definition of Garage Apartment itself (§7.01.01). Note that owner-occupancy rules vary by state law — California and several other states have eliminated this requirement for standard ADUs.
The ADU permit review timeline in Frisco is typically 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. 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). Pre-approved plans availability: No city pre-approved ADU plan library was found — Confirm with Frisco Development Services (972-292-5301).
Average ADU rental income in Frisco: 1-bedroom units rent for $1,300-$1,750/month, 2-bedroom units for $1,700-$2,350/month. Short-term rentals: 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. Expected ROI: 5-8% annual return.
The minimum lot size for an ADU in Frisco is No ADU-specific minimum lot size — the underlying district's minimum lot area applies: 7,000 sq ft in SF-7, 8,500 in SF-8.5, 10,000 in SF-10, 12,500 in SF-12.5, 16,000 in SF-16, 4,500 in OTR, 1 acre in RE and 2 acres in AG (Frisco Zoning Ordinance §2.06.04). This applies to detached ADUs — garage conversions and JADUs may have different or no lot size requirements.
Garage conversions are one of the most popular and affordable ADU options. In Frisco, a garage conversion typically costs $65,000-$150,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
Tell us about your project and we'll connect you with ADU builders serving Frisco. Free, no obligation — you choose who to work with.
🔒 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.