ADU rules in Woonsocket

Woonsocket allows one ADU per lot in every residential district (R-1 to R-4) only where it fits one of the three by-right circumstances that §6.18-2 copies from R.I. Gen. Laws 45-24-73(a). For a detached unit that means converting an existing detached accessory building (garage, barn) without expanding its footprint, on any lot; building a new detached unit on a lot of 20,000 sq ft or more whose primary use is residential, which covers most conforming R-1 lots (the R-1 minimum lot is 25,000 sq ft); or building one on an owner-occupied property as a reasonable accommodation for a family member with disabilities. A new backyard cottage on a typical R-2, R-3 or R-4 lot (10,000, 7,000 and 6,000 sq ft minimums) has no by-right path; the city's October 2026 ADU quick reference says such projects need zoning relief from the Zoning Board of Review, heard as dimensional variances.

An internal ADU (basement, attic or other conversion inside the existing house, or inside an existing attached accessory structure) qualifies under §6.18-2(3) and is a by-right permitted use on any residential lot, with no zoning relief needed even where the existing structure is legally nonconforming (45-24-73(b)(2)(vii)). An addition that expands the house's footprint is by right only on a lot of 20,000 sq ft or more or as a disability accommodation on an owner-occupied property; elsewhere it needs zoning board relief. The local definition (§18(d), Ch. 8558) matches the state definition, so ADUs are allowed with single-family and multifamily principal dwellings alike.

§6.18-3 says ADUs 'shall be limited to' the state's minimum figures: a studio or one-bedroom unit of 900 sq ft or 60% of the principal dwelling's floor area, whichever is less, and a two-bedroom unit of 1,200 sq ft or 60%, whichever is less. The ordinance copies the statute's 'of at least' wording, so the local cap sits exactly at the 45-24-73(b)(1) floor; the city's ADU quick reference reads it the same way (900/1,200 sq ft or 60% if smaller). Up to two bedrooms are allowed (45-24-73(b)(2)(x)). Woonsocket sets no separate accessory-building height, so a detached ADU follows the district limits: 35 ft and 2.5 stories in R-1, 30 ft and 2 stories in R-2, 30 ft in R-3 and R-4 (more with added side yards). Unattached accessory buildings may sit 5 ft from side and rear lines in R-2 to R-4 and 15 ft in R-1, and district lot coverage applies (25% R-1, 35% R-2, 50% R-3 and R-4).

Woonsocket's ADU section imposes no general owner-occupancy rule. Owner occupancy appears only in the disability-accommodation path, §6.18-2(1) ('On an owner-occupied property as a reasonable accommodation for family members with disabilities'), copied from 45-24-73(a)(1). ADUs inside an existing footprint or on a lot of 20,000 sq ft or more carry no owner-occupancy requirement, and the city's quick reference says so ('This is the only path that requires owner occupancy'). §6.18-4 bars the restrictions listed in 45-24-73(b)(2), including revoking a legally established ADU on transfer of title or occupancy ((b)(2)(xii)). The 2025 amendment struck the former zoning-board 'accessory family dwelling unit' regime in §7.2-7.

§5.1-3.13, as amended by Ch. 8558, requires 'two (2) spaces ... for each dwelling unit, plus one (1) space for each accessory dwelling unit'. That fits within 45-24-73(b)(2)(viii), which bars requiring more than one space per bedroom of the ADU; the city's ADU quick reference applies the cap so that a studio with no bedroom needs no added space. The principal dwelling keeps its own two spaces. The council twice voted down eliminating residential parking minimums (25-O-43 in 2025; 26-O-03, a Monument Square to Main Street pilot, defeated 6-1 on 6-15-2026), so the one-space rule stands.

An ADU that fits a §6.18-2 circumstance 'shall be a permitted use in all residential zoning districts through an administrative building permit process only' (§6.18-1, mirroring 45-24-37(e)); the applicant files a building permit with the Building and Zoning office, with no hearing. Woonsocket created no special use permit for other ADUs, and the use table in §4.4 has no ADU row (§3.2 prohibits unlisted uses). An ADU outside the three circumstances therefore needs relief from the Zoning Board of Review, which the city's October 2026 quick reference says the board currently hears as dimensional variances. §6.18-5 adds that such an application is not, by itself, a minor or major land development project, and §6.18-7 allows unified development review for applications that include ADUs.

State law bars ADUs from being offered or rented for tourist or transient use (occupancy under 30 consecutive days) or through a hosting platform (45-24-73(b)(8), terms defined in 42-63.1-2), and Woonsocket repeats the bar in §6.18-9 (codified as '16.18-9'). Long-term rental is allowed, and the city may not restrict tenants by family relationship or age (45-24-73(b)(2)(i), adopted by §6.18-4); the old family-only accessory family dwelling unit rule was repealed in 2025. Woonsocket's City Code has no short-term rental registration or licensing ordinance (a scan of every chapter on clerkshq.com on 2026-10-15 found none), so only the state DBR registration under 42-63.1-14 applies to short-term rentals of the main house.