ADU rules in South Kingstown

South Kingstown's ordinance calls ADUs "accessory apartments" and allows one per lot, inside the house or "as an accessory structure" (Sec. 503.2.A). The local gates are tight: a unit on public sewer may go in any district that allows dwellings, but only on a lot meeting the larger accessory-apartment minimums in the Sec. 401 table (for example 15,000 sq ft in R10, 30,000 in R20, 45,000 in R30). Without public sewer the text allows one only in R200 by special use permit, and never inside the Carrying Capacity Overlay District around the salt ponds and Narrow River (Sec. 503.2.C and D). Detached units also need 15 ft side and rear setbacks (Sec. 402 note B). State law (R.I. Gen. Laws 45-24-37(e) and 45-24-73(a)) overrides these gates for a lot of 20,000 sq ft or more, a conversion within an existing footprint, or a disability accommodation. In 2026 the zoning board has treated 20,000 sq ft as the lot area needed for an ADU and has granted dimensional variances on smaller lots.

An accessory apartment may be "within" a principal residence (Sec. 503.2.A) and must then meet the principal-use dimensional rules (Sec. 503.2.B.1). The same sewer, lot-size and Carrying Capacity Overlay gates apply as for detached units, so an attached unit is not by right everywhere. State law makes a conversion inside the existing house footprint, and any ADU on a lot of 20,000 sq ft or more, by right through a building permit. Footprint-expanding additions on smaller lots fall back to the local gates or a variance; ZBR-26-7 (312 Woodruff Avenue, R10, 19,782 sq ft) needed a dimensional variance for an attached 1,040 sq ft ADU.

Sec. 503.2.E.2 caps an accessory apartment at 750 sq ft measured to the exterior walls, including covered porches but excluding access stairs, with relief by special use permit. The Article 12 definition also limits it to one bedroom and two occupants and requires it to be smaller than the house. Both are below the statutory floor: 45-24-73(b)(1) requires a town to allow at least 900 sq ft (studio or one bedroom) and 1,200 sq ft (two bedrooms), or 60 percent of the principal dwelling if that is less, and (b)(2)(x) bars limiting an ADU to fewer than two bedrooms. The May 20, 2026 zoning board minutes (ZBR-26-11) describe the maximum ADU floor area as 1,200 sq ft and grant a variance above it, so the town applies the state figure. Accessory building height is 15 ft in R10 to R40 and 20 ft in R80 and R200 (Sec. 401).

Sec. 503.2.E requires that the accessory apartment be "in the same ownership as the principal residence" and that "either the principal residence or the accessory apartment is occupied by the owner for at least six (6) months of the year." Before a certificate of occupancy, the owner must record a deed restriction that runs with the property. This is an ongoing requirement, and the text applies it to every accessory apartment. State law requires owner occupancy only for the disability-accommodation ADU under 45-24-73(a)(1). For ADUs on 20,000 sq ft lots or within an existing footprint the statute imposes none, and 45-24-73(b)(2)(xii) bars revoking a legal ADU on transfer of title.

The Sec. 711 parking table lists "Residence with accessory apartment: 2 for principal dwelling; 1 for accessory apartment." Sec. 712 requires all spaces to be surfaced, allows at most two outdoor spaces in the front yard, and requires screening where the apartment has more than two outdoor spaces. The state cap is one off-street space per ADU bedroom (45-24-73(b)(2)(viii)), so a one-bedroom unit's single space complies. A two-bedroom ADU allowed under state law could be required to have up to two.

A sewered accessory apartment that meets the Sec. 401 lot-size row and the Sec. 503.2 standards needs only a building permit, a deed restriction and a certificate of occupancy. An unsewered unit is allowed only in R200 by special use permit from the zoning board of review (Sec. 503.2.C), with mandatory septic conditions. Size relief above 750 sq ft is also by special use permit (Sec. 503.2.E.2), and lot-area or height shortfalls go to the board as dimensional variances (Secs. 401 and 907). Under 45-24-37(e), an ADU on a lot of 20,000 sq ft or more, inside an existing footprint, or as a disability accommodation must be allowed through an administrative building permit only.

State law bars offering or renting any ADU "for tourist or transient use or through a hosting platform" (45-24-73(b)(8)), which means stays under 30 consecutive days. Long-term rental of the ADU is allowed. Since 2025 every rental unit must be registered each year with the zoning official under Zoning Ordinance Art. 5.5 (adopted 10-14-2025, amended 2-9-2026 and retroactive to 12-20-2025). The fee schedule is set by council resolution; the town lists $50 per long-term unit and $300 per unit rented for 30 days or less. Sec. 503.2.B.3 bars renting rooms or taking boarders in either the house or the apartment. The definition limits the apartment to two occupants, a local cap the state's two-bedroom rule undercuts. Units given the Ch. 17 tax abatement need leases of at least 12 consecutive months (Sec. 17-86(d)), and the same-ownership rule in Sec. 503.2.E.3 bars selling the ADU separately.