Everything homeowners ask about building an ADU in Frisco — answered with 2026 data.
Yes, ADUs are allowed in Permitted by right ("P") in AG, RE, SF-16, SF-12.5, SF-10, SF-8.5, SF-7 and OTR under the Use Chart, Frisco Zoning Ordinance §3.02 (Residential Uses: Garage Apartment; Guest House); not listed in PH, 2F, TH, MF-15, MF-19 or MH. In PD – Planned Development districts, which cover much of Frisco, the chart defers to the PD ordinance — ask Development Services (972-292-5301) for your PD's use list. §4.06.03 allows the unit "as an incidental use on the same lot or tract as the main dwelling unit" in Frisco, TX. The maximum size for a detached ADU is No floor-area cap: §4.06.03 sets location, permit, rental and setback standards for a Garage Apartment or Guest House but no maximum size. What binds 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 (§2.06.04). A detached unit is a Guest House, defined in §7.01.01 only as "an accessory building used to house guests of the owner(s)" — confirm with Development Services before adding a kitchen. Attached ADUs can be up to No size cap stated. A Garage Apartment must be attached to a garage, 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 $140,000-$350,000. The cost per square foot averages $250-$400. Garage conversions are more affordable at $30,000-$100,000, while prefab ADUs cost $150,000-$300,000. Permit fees add Building permit $150 for the first 300 sq ft plus $0.50 per added sq ft ($400 for 800 sq ft), plus a $300 application fee and $50-per-trade electrical, mechanical and plumbing permits, per the FY26 Comprehensive Fee Ordinance 2025-09-48 (effective Oct 1, 2025); FY27 figures apply from Oct 1, 2026. to your budget. See our detailed Frisco ADU cost guide.
Detached ADUs in Frisco can be up to No floor-area cap: §4.06.03 sets location, permit, rental and setback standards for a Garage Apartment or Guest House but no maximum size. What binds 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 attached to a garage, 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. The code does define Servant's Quarters (§7.01.01), an accessory dwelling limited to immediate family or full-time domestic staff, but only Garage Apartment and Guest House appear in the Use Chart. 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 (§2.06.04). The 8-foot figure in Figure 4.06.04.1 is the condition for a 3-foot rear setback on alley-backing lots (with a solid fence or wall of the same height on the rear lot line), not a general accessory-structure height cap. 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", for front, side and rear, so it does not get the 3-foot (note A) or 10-foot (note B) rear setback ordinary accessory buildings use (§4.06.03(D), §4.06.04(G)). 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 (§2.06.04). 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, SF-16 and RE, 20 feet in AG and 6 feet in OTR, with larger corner-lot side yards in each (§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, requirement 2). Front setback: Same as the primary structure (Figure 4.06.04.1, note D) — 25 feet in SF-7, SF-8.5 and 2F, 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 (§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, requirement 3). Note that garage conversions may be exempt from setback requirements if the existing structure is already within the setback area.
No separate spaces for the apartment. The Use Chart's parking column sends Garage Apartment and Guest House to schedule item (19), "Dwellings, single-family and two-family", which applies §4.04.02(E): two enclosed garage 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. Converting the garage itself into living space removes those required enclosed spaces, so the apartment goes above or beside the garage, not in it. 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" (§4.06.03(C)(2)). The unit 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). No affidavit or deed restriction is required by the text. 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 Not published. Frisco's Residential Permits page lists the steps (electronic application, fees assigned by email, pre-screen, Department Review, permit download) but no review-time target — confirm current turnaround with Plans & Permits (972-292-5301). Plan check: Standard residential plan review through the electronic permit portal; plan revisions are billed at $50 per hour (Ordinance 2025-09-48). Budget for the facade rule: the exterior of an accessory structure must use the same exterior material as the main building and meet or exceed §4.07.09 Exterior Construction of Main Buildings (100% masonry), with fiber cement siding allowed only on a structure of 200 sq ft or less in a single-family or two-family district, or where the main house is itself all wood or vinyl siding (§4.06.05). Pre-approved plans availability: None. No city pre-approved garage apartment or ADU plan library appears on Frisco's Residential Permits page or in the fee ordinance — confirm with Development Services (972-292-5301).
Average ADU rental income in Frisco: 1-bedroom units rent for $1,500-$2,100/month, 2-bedroom units for $2,000-$2,600/month. Short-term rentals: Allowed with a city short-term rental permit. Expected ROI: 5-12% gross rent yield.
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 north of Main Street (2,250 south of Elm Street), 1 acre in RE and 2 acres in AG (§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 $30,000-$100,000. The key advantages are lower cost (no foundation work), potential setback exemptions, and faster permitting. Read our complete garage conversion guide.
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