ADU Pass
Ashaway
ADU Pass helps homeowners in Ashaway, Washington County, Rhode Island navigate the permit paperwork for building an accessory dwelling unit. This area covers 1 ZIP code.
Map
ADU details
ADU legality: allowed
ADUs by right under default RIGL Sec 45-24-73 minimums applied through the Town of Hopkinton Building & Zoning Department. Most Ashaway parcels are on private wells and septic; municipal water/sewer service is limited.
Cost scenarios
| Scenario | Sq ft | Permit | Build | Total |
|---|---|---|---|---|
| minimum | 200 | $1,900 | $52,000 | $53,900 |
| 600 | 600 | $2,700 | $174,000 | $176,700 |
| midpoint | 900 | $3,500 | $261,000 | $264,500 |
| maximum | 1,200 | $4,400 | $348,000 | $352,400 |
Fee breakdown (as of 2026-04)
Permitting process
- Pre-application research at Hopkinton Building & Zoning (~5d)
Visit Charles Niles Complex (395 Woodville Road) or call 401-377-7771. Building Official Anthony L. Santilli. Confirm zoning district under Hopkinton's R-1, R-2, RFR districts, and any historic-district overlay near Ashaway village center. - RIDEM septic system design (most Ashaway parcels are on private septic) (~35d)
If existing OWTS cannot accommodate the additional dwelling unit's design flow, a RIDEM-approved septic engineer must design and submit a new system or upgrade. RIDEM ISDS approval typically 30-45 days. - Submit zoning certificate application to Hopkinton Building & Zoning (~1d)
Zoning Certificate Application is the entry document. Required: site plan, floor plan, elevations, IECC 2018 compliance docs, RIDEM ISDS approval where applicable. - Zoning compliance review (Zoning Enforcement Officer) (~14d)
Hopkinton Zoning Enforcement Officer reviews against default state ADU minimums (RIGL Sec 45-24-73) plus Hopkinton's lot, setback, and parking requirements. - Building permit submittal via statewide e-permitting portal (~1d)
Building permit at permits.ri.gov (Hopkinton participates in the statewide system). Plan review by Building Official. - Building plan review (combined building / electrical / plumbing / mechanical) (~25d)
Hopkinton Building Official routes plans to MEP inspectors. Rural town with small staff - allow extra calendar time. - Permit issuance and fee payment (~3d)
Fees per Hopkinton Town Hall fee schedule. Pay via state portal. - Construction inspections + Certificate of Occupancy
Foundation, frame, MEP rough, insulation, final, then CO. Septic final inspection coordinated through RIDEM.
Viability (permitted uses)
- Long-term rental: yes Long-term rental of ADU permitted under default RIGL Sec 45-24-73.
- Short-term rental: with-restrictions Hopkinton does not have a dedicated STR ordinance. STR of an ADU permitted but standard residential nuisance / noise ordinances apply.
- Office rental: no ADU is dwelling-unit use only.
- Home office: yes Home occupation permitted in residential districts subject to use-table conditions.
- Studio / workshop: yes Personal artist / workshop studio permitted as accessory residential use.
- Agriculture: with-restrictions Hopkinton's RFR Rural-Farming-Residential district allows broader agriculture; ADU use itself remains residential.
- Relative support: yes Family-occupancy ADU permitted; in-law suite is the dominant use case in rural Hopkinton.
Contacts
Staff: Anthony L. Santilli (Building Official), Hopkinton Planning Department (Subdivision / planning intake)
Utilities
- Water: Private wells throughout Ashaway village; no Ashaway-specific public water utility · $12,000
- Sewer: Private OWTS / septic systems regulated by RIDEM ISDS - no municipal sewer in Ashaway · $28,000
- Electric: Rhode Island Energy · 21d connect · $1,900
- Gas: Rhode Island Energy gas mains do not extend into Ashaway; propane is the typical heat source · $3,000
Property values & taxes
Market rent by ADU size
| Sq ft | Rent |
|---|---|
| 400 | $1,150/mo |
| 700 | $1,500/mo |
| 1,200 | $1,900/mo |
Construction timeline
Realistic total: best 8mo · typical 13mo · worst 20mo
Rural Hopkinton GC market is very shallow; many contractors based in Westerly or Charlestown. Septic-system permitting and installation is the longest single-step delay.
Modular pathway RI State Building Code Commission - Modular Home Program · inspectors are rare with modular
Rural narrow roads through Hopkinton; Route 3 (Main Street Ashaway) tight at the village center. Module placement on rural acreage easier than dense villages.
Financing
State ADU loans:
- RIHousing - state mortgage / refi products eligible for ADU (Rhode Island Housing and Mortgage Finance Corporation)
Insurance impact
Septic / well systems shift loss profile; flood AE zone parcels need NFIP policy.
HOA prevalence & preemption
Ashaway has very low HOA prevalence - rural village with mostly individual deeds.
Regulatory overlays (3)
- wetlands — Ashaway River and tributaries trigger RIDEM Freshwater Wetlands review within 50/200 ft buffers; Crandall Brook also relevant · +30d · +6% cost
Most of Ashaway village is within RIDEM jurisdictional buffers due to river proximity. (map) - flood-zone — FEMA SFHA Zone AE along Ashaway River through village center · +14d · +8% cost
Ashaway River AE zone affects mill housing along Main Street and adjacent lots. (map) - wellhead-protection — RIDEM-mapped Sole Source Aquifer protection in southwest RI · +10d · +3% cost
Septic siting and design subject to RIDEM aquifer protection setbacks. (map)
Technical envelope (climate & building code)
Climate & energy code
Building code
Amendments:
- Rhode Island State Building Code (SBC-1) - amendments to IRC 2018 — RI removes IRC R313 sprinkler mandate; modifies frost depth and energy provisions.
Contractor market (aggregate)
Legal history (timeline)
Current ordinance: Town of Hopkinton Code of Ordinances - Zoning chapter; default state statute Sec 45-24-73 controls in absence of local ADU customization, adopted n/a, last amended n/a
- 1824-01-01 — Ashaway Line & Twine Mfg. Co. founded by Capt. Lester Crandall (other)
Continuous family-owned mill at the heart of the village, oldest single-family RI enterprise. In 1939 produced the world's first commercial nylon product (DuPont fishing line).
Effect: Anchors the village historic district pattern - mill housing surrounding the Ashaway Line & Twine works on the Ashaway River. Influences any historic-preservation review touching village-center parcels. - 2024-06-25 — RI H 7062 / S 2998 signed - statewide ADU mandate codified at RIGL Sec 45-24-73 (state-law)
Required every Rhode Island municipality to permit one ADU by right on owner-occupied 1-3 family residential lots, effective 2024-09-01.
Effect: Hopkinton (and therefore Ashaway) must process ADU applications under default state minimums absent a local customization.
Known issues (1)
- policy-gap (since 2024-09) — Builders must read RIGL Sec 45-24-73 directly for the operating standard; some local interpretive questions (e.g., setbacks for detached ADUs on RFR-zoned acreage) await Town Council clarification. (source)
Rhode Island state — ADU law and programs
State ADU law
Rhode Island enacted statewide ADU preemption in 2024 through H 7062 (chief sponsor Rep. June Speakman and colleagues; co-sponsored in the Senate as S 2710), which amended the Zoning Enabling Act (Title 45, Chapter 24). Municipalities must permit ADUs by-right on any lot containing a single-family dwelling, subject only to uniform minimum standards set by the statute. One of the most ADU-friendly state statutes in the country as of 2025.
- R.I.G.L. § 45-24-73 — Design standards required for accessory dwelling units; Consistent statewide treatment of accessory dwelling units required — Core ADU standards added by H 7062 (2024). Requires municipalities to permit ADUs by-right. Caps 1-bedroom and studio ADUs at 900 sqft or 60% of the principal dwelling's floor area, whichever is less. Caps 2-bedroom ADUs at 1,200 sqft or 60%, whichever is less. Prohibits owner-occupancy requirements. Caps additional parking at 1 off-street space per bedroom. Prohibits ADU-specific impact fees. Voids HOA, condominium, and similar private-covenant restrictions that conflict with the statute as against public policy.
- H 7062 (2024 RI General Assembly) — An Act Relating to Housing — Accessory Dwelling Units — The enacting bill. Also cited by municipalities adopting conforming ordinances (Providence 2024 Chapter 3584, East Providence 2024 ADU Ordinance, South Kingstown 2024-07-12 regulations).
State HOA preemption
R.I.G.L. § 45-24-73 explicitly voids homeowners' association, condominium association, or similar private-covenant restrictions on ADUs when those restrictions conflict with the statute's ADU minimums. The preemption is framed as a public-policy void, meaning the offending covenant is unenforceable rather than simply regulated. Pre-existing ADU-friendly covenants remain valid (the statute only void conflicting restrictions). Applies to all common-interest communities governed by the Rhode Island Condominium Act (R.I.G.L. Title 34, Chapter 36) and Rhode Island Condominium Ownership Act (Title 34, Chapter 36.1), as well as HOAs in planned-community subdivisions.
- R.I.G.L. § 45-24-73 (HOA preemption clause added by H 7062 (2024)) — Provides that private covenant restrictions imposed by condominium associations, homeowners' associations, or similar residential property governing bodies that conflict with the ADU provisions are void as against public policy. Drafted broadly — covers declarations, bylaws, rules and regulations, and recorded covenants.
State financing programs
RIHousing, the state's housing finance agency, operates an ADU financing program built around the FHA 203(k) loan product. Covers attached and interior ADUs for both purchase and refinance. Detached ADUs are NOT eligible. Requires mandatory homebuyer education, use of an FHA-approved 203(k) consultant, and a RI licensed and insured contractor. No state-specific grant program for ADUs is in effect as of 2026-04-21; the federal 203(k) rails are the production vehicle.
State housing programs
Rhode Island does not currently operate a single statewide pre-approved-ADU-plan catalog (as California's CalHFA and Washington's Commerce plan libraries). Implementation of the 2024 ADU law is happening municipality-by-municipality, with the Executive Office of Housing (EOH) coordinating technical assistance. Providence published a citywide ADU Guide (February 2025) as the leading model; East Providence adopted a conforming ordinance in 2024; South Kingstown published regulations in 2024. RIHousing runs the ADU financing side (see stateFinancing).
Federal (United States) — ADU-relevant rules and programs
Federal ADU law
The United States has no federal statute that directly regulates accessory dwelling unit entitlement or design. Land-use authority over ADUs resides with states and local governments under the traditional police power. Federal engagement is limited to financing (Fannie/Freddie/FHA/VA/USDA), flood insurance (FEMA/NFIP), and discretionary housing programs (HUD), which are recorded in sibling sections of this file.
Federal financing programs
Federal housing-finance agencies and GSEs set nationwide underwriting rules that govern whether an ADU can be financed, appraised, and counted toward mortgage qualifying income. The relevant actors are Fannie Mae, Freddie Mac, FHA (HUD), VA, and USDA Rural Development.
Federal tax credits
There is no ADU-specific federal tax credit. ADUs may incidentally qualify for existing federal energy-efficiency and clean-energy tax credits when the ADU construction includes qualifying measures.
Federal housing programs
HUD administers several discretionary programs that can fund ADU-related activity at the grantee's election, but none is an ADU-specific program.
ZIP Code
- 02804
Post Office
- 129 Main St, 02804