ADU rules in Frisco

Frisco does not use the term accessory dwelling unit; its detached form is the Guest House, an accessory building housing guests of the owner that must be built separate from the main dwelling. It is allowed by right as an incidental use on the same lot as the main home in the AG, RE, SF-16, SF-12.5, SF-10, SF-8.5, SF-7, and OTR districts, and the code lets it be rented (long term) while the main dwelling is owner occupied. The city's STR ordinance treats a guest house as a dwelling that can be a home, confirming it is separately occupiable.

The attached form is the Garage Apartment, a dwelling unit attached to a garage either above or at garage level, permitted by right in the same eight districts. The garage itself may be attached to the house through an open breezeway or be a detached garage, so this use also covers backyard above-garage units. The definition presumes the main structure is detached and owner occupied. The ordinance does not address an interior secondary suite within the main house as a distinct use.

Unlike many cities, Frisco's ordinance sets no explicit floor-area maximum for these units, so practical size comes down to what lot coverage, setbacks, and height allow on the specific lot. Lot coverage counts main and accessory structures together, and larger accessory buildings must be finished in the same exterior materials as the house (masonry-match thresholds at 120 or 200 sq ft depending on material).

Owner occupancy of the main house is mandatory whenever the Garage Apartment or Guest House is rented or offered for rent; that is the rental gate in §4.06.03(C)(2). The Garage Apartment definition additionally builds in an owner-occupied main structure regardless of rental. A Guest House used only to house the owner's guests carries no separate occupancy test beyond its definition tying it to the owner of the main residence.

Frisco does not add extra required spaces for a garage apartment or guest house; the lot must simply meet the standard residential minimum. Required parking must be on the same lot and paved concrete unless the Director of Engineering Services approves alternatives; enclosed and stacking spaces must be at least 9 by 20 ft.

The Use Chart marks both Garage Apartment and Guest House with 'P' (permitted use, not a specific-use-permit 'S') in AG, RE, SF-16, SF-12.5, SF-10, SF-8.5, SF-7, and OTR; the chart shows no permission in PH, 2F, TH, MF-15, MF-19, or MH. Construction requires only a standard building permit. In OTR, accessory buildings must also match the scale and character of the main structure and need an approved facade plan before permit issuance.

Frisco is notably permissive for a DFW suburb: separate rental of the unit is expressly authorized, conditioned only on the owner living in the main house. Occupancy is not limited to family or servants for these two uses (a separate Servant's Quarters definition with a family-or-domestic-staff limit exists but is not a listed use in the current Use Chart). STR operators register through the city's vendor portal and renew yearly.