ADU rules in Plano

Plano's ADU is the Backyard Cottage: a detached dwelling unit (kitchen, sleeping, and sanitation per the Dwelling Unit definition) on the same lot as a detached single-family home. It is a permitted accessory use, one per lot, in every conventional single-family district (SF-20, SF-9, SF-7, SF-6, UR, PH) and also in SFA, 2F, GR, MF-1 through MF-3, MH, RCD, UMU, and BG, always subject to §15.1800. Minimum lot size is 6,000 sq ft. It is not allowed in the A or ED districts; the ED estate district instead allows accessory dwelling units for family members with one acre of lot per unit.

Plano authorizes only the detached form: Backyard Cottage is defined as a detached dwelling unit, and a single-family dwelling is a building occupied by not more than one household, so a separately occupiable attached second unit would make the building a two-family dwelling, allowed only in 2F, GR, and multifamily districts. The general accessory-building rule also requires accessory buildings to be detached and bars them from use as living quarters except where specifically listed. The closest attached arrangement recognized is an accessory second kitchen in the main building or in servants' quarters within it, which remain part of the single household's dwelling.

The cottage must stay within the district's maximum lot coverage, sit at least 10 ft from the main dwelling and behind it, be architecturally compatible, and be on a permanent foundation. In the ED estate district the separate accessory-dwelling-unit rules set a 500 sq ft minimum and one acre of lot area per dwelling unit, with no stated maximum.

§15.1800 was read in full and contains no requirement that the owner live in either the main house or the cottage, and a search of the whole zoning ordinance found no owner-occupancy condition on backyard cottages. What Plano requires instead is a city-approved covenant recorded with the county before the building permit issues, barring separate sale of the cottage and requiring its removal if the covenant is violated.

The Article 16 residential parking schedule lists Backyard Cottage at 1 space per dwelling unit on top of the main home's 2 spaces. Front-yard driveway parking is allowed only where that matches the prevailing design on the block, any front driveway must be shared with the main dwelling, and curb cuts other than alleys are capped at 24 ft wide.

The §14.100 use table marks Backyard Cottage 'P' (permitted by right) with footnote 51 in every district where it is allowed; no specific use permit or public hearing is involved. The process is a building permit, preceded by city review, approval, and county recording of the no-separate-sale covenant. The exception is the ED estate district, where the district's own accessory dwelling units require site plan approval instead.

Occupancy of any dwelling unit is bounded by the Household definition (relatives plus no more than 4 unrelated adults). For rentals under 30 days, §15.2300 permits STR uses only in nonresidential districts (except O-1), limited multifamily situations, or as nonconforming uses operating before May 15, 2023, so a new STR in a single-family neighborhood is not allowed. Any lawful STR must register annually under Code of Ordinances Ch. 6, Art. XXIV ($300 application fee, $1M liability insurance, hotel occupancy taxes; Ord. No. 2024-4-14). In the ED district, accessory dwelling units are permitted for use by family members.