ADU rules in Narragansett

Narragansett allows one ADU per lot by right only in the three circumstances it copied from R.I. Gen. Laws 45-24-73(a): a lot of 20,000 sq ft or more in residential use, a unit inside the existing footprint of the house or of an existing attached or detached accessory structure (a garage conversion, for example), or an owner-occupied property where the unit is a reasonable accommodation for a family member with a disability. The Table of Use Regulations lists 'Accessory dwelling unit' as P in R-80, R-40, R-20, R-10 and R-10A (X in every business, industrial and public zone) but sends the reader to section 7.3(6), which offers no other path. A new detached cottage on a lot under 20,000 sq ft (most R-10 and R-10A lots) therefore has no by-right or special use permit route in the ordinance. Under the directory's Rhode Island convention this is 'conditional': the only by-right path is the statutory circumstances.

An internal conversion (basement, attic, part of the existing house) qualifies by right anywhere in the five residential zones because it stays within the existing footprint under §7.3(6)(a)(3). An attached ADU 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; on smaller lots the ordinance offers no route for an expanding addition. The ADU definition in §2.2 matches the state definition word for word and covers a unit that is part of an expanded or remodeled primary dwelling, and ADUs are allowed with single-family or multifamily principal dwellings.

Section 7.3(6)(b) sets the caps exactly at the state minimums of 45-24-73(b)(1), so the local cap meets but does not exceed the statutory floor. ADUs may not contain more than two bedrooms. A detached unit is also an accessory structure: one over 144 sq ft or 13 ft tall must meet the zone's full front, side and rear setbacks and is limited to 18 ft in height, and combined coverage of all buildings on the lot may not exceed the zone's maximum building coverage in §6.4 (§6.5 for substandard lots of record). Floor area is gross floor area as defined in §2.2, which excludes basements, cellars and garage space.

The only owner-occupancy language in section 7.3(6) is the statutory disability-accommodation circumstance: an ADU on 'an owner-occupied property as a reasonable accommodation for family members with disabilities.' ADUs that qualify on a 20,000 sq ft lot or within an existing footprint carry no owner-occupancy requirement, at application or afterward. The older 'Accessory family dwelling unit' definition (family-only, no separate entrance needed) still sits in §2.2 but no longer appears in the use table or in any operative section.

Section 7.3(6)(b)(4) requires one additional off-street parking space for each bedroom in the ADU, the most a town may require under 45-24-73(b)(2)(viii). The general residential parking rule in §7.9(1)(a) (one 200 sq ft space per bedroom with a minimum of two spaces per dwelling unit) would demand more for a studio or one-bedroom unit; the ADU-specific rule and the state cap control. Section 7.9 also says garage space counted toward required parking may not be converted to living space unless the spaces are relocated on site or the zoning board grants relief, which matters for garage conversions.

An ADU meeting 45-24-31 and 45-24-73(a) is 'a permitted use in all residential zoning districts' and 'shall be permitted through an administrative building permit process only' (§7.3(6), restating 45-24-37(e)); the application goes through the town's E-Permit building permit system. The ordinance creates no special use permit route for ADUs outside the three circumstances, so a homeowner who does not qualify would need a variance from the zoning board of review, and 45-24-73(b)(3) bars treating such an application, by itself, as a land development project. A detached accessory structure over 1,500 sq ft ground floor area or over 18 ft tall needs a special use permit, but the ADU size caps keep a compliant ADU well under that threshold.

State law and the town ordinance both bar renting an ADU for tourist or transient use or through a hosting platform (§7.3(6)(b)(5), 45-24-73(b)(8)), so the town's short-term rental permit program (Chapter 14, Article XVII, capped at 900 permits for the 2026-27 year) is not available for an ADU. Narragansett goes further: any ADU used as a rental 'shall be leased for a term of no less than 12 consecutive months' (§7.3(6)(d)), which also rules out the town's common academic-year and summer-only lease patterns. Every rental unit must be registered with the building inspector by August 31 each year ($120 per unit, $300 late fee, $500 minimum fine for violations). ADUs may not be split off or sold separately by subdivision, condominium, ground lease or tenancy in common (§7.3(6)(b)(6)). In R-10, R-10A and R-20, a dwelling unit that is not in an owner-occupied building may house at most five college students, one per legal bedroom (§7.23).