Rhode Island ADU permit requirements
Last reviewed: June 20, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in Rhode Island means pulling a building permit from the local authority that issues it. Rhode Island has a statewide ADU law that sets baseline standards local agencies must follow. ArchPermit tracks 14 source-cited requirements (12 required, the rest conditional) for this jurisdiction. These requirements were last reviewed June 20, 2026; confirm the exact forms and fees with the local permitting authority.
Rhode Island has a statewide ADU law. This baseline reflects that law plus the universal new-dwelling deliverables. Your local city or county still administers the permit and may add its own forms and fees — confirm the exact checklist with them.
Rhode Island's 2024 amendment to R.I. Gen. Laws § 45-24-73 allows one ADU per lot by right in specified cases (lots ≥20,000 sq ft, within the existing footprint, or as a disability accommodation on an owner-occupied lot). The local AHJ administers permits; non-qualifying ADUs may still need zoning relief.
- Adopted building code compliancerequired
The ADU must comply with Rhode Island's adopted residential building code: RI One- and Two-Family Dwelling Code (RISBC-2, 2018 IRC). Confirm the in-force edition with the local AHJ.
source · reviewed 2026-06-20 - Building cross-sectionsrequired
Cross-sections through the structure showing ceiling heights, wall/roof assemblies, insulation, and fire/sound-rated assemblies where required.
source · reviewed 2026-06-20 - Egress & life-safetyrequired
Emergency escape and rescue openings (egress windows), smoke and carbon-monoxide alarms, and required exits per the adopted residential code.
source · reviewed 2026-06-20 - Energy code compliancerequired
Energy-code compliance documentation for the conditioned space. Rhode Island: RI Energy Conservation Code (SBC-8, 2018 IECC).
source · reviewed 2026-06-20 - Exterior elevationsrequired
Elevations of each affected building face showing height, exterior materials, and openings; existing vs. proposed where exterior changes occur.
source · reviewed 2026-06-20 - Floor plansrequired
Dimensioned floor plans of the ADU (and affected areas of the primary dwelling) showing rooms, uses, door/window locations, egress, and fixture/equipment locations.
source · reviewed 2026-06-20 - Foundation planrequired
Foundation plan with footing/stem-wall sizes and details (or a cited site-specific design), per the adopted residential code.
source · reviewed 2026-06-20 - Framing / structural plansrequired
Floor, wall, and roof framing showing member sizes, spans, spacing, connections, and lateral bracing; structural calculations where the framing is non-conventional.
source · reviewed 2026-06-20 - Local zoning / setback compliancerequiredverify locally
Compliance with the local jurisdiction's zoning: permitted use, setbacks, height, lot coverage, and any ADU-specific standards. These are set locally — confirm with the permitting agency.
source · reviewed 2026-06-20 - Mechanical / plumbing / electricalrequired
HVAC, plumbing fixtures and lines, and electrical (panels, circuits, outlets, lighting, smoke/CO alarms) for the new unit.
source · reviewed 2026-06-20 - No short-term / transient rentalrequiredverify locally
ADUs may not be offered for tourist/transient use or via a hosting platform.
source · reviewed 2026-06-20 - Site / plot plan (to scale)required
Scaled site plan showing property lines, setbacks, existing structures, the proposed ADU footprint with dimensions to property lines, driveways/parking, and utility locations.
source · reviewed 2026-06-20 - By-right qualifying conditionsconditionalverify locally
One ADU by right where: lot ≥20,000 sq ft and primarily residential; OR within the existing footprint without expansion; OR a disability accommodation on an owner-occupied lot.
source · reviewed 2026-06-20 - Statutory ADU size standardsconditionalverify locally
Studio/1BR ADU up to 900 sq ft or 60% of the principal dwelling (lesser); 2BR up to 1,200 sq ft or 60% (lesser).
source · reviewed 2026-06-20