Prudence Island

1. OWTS septic feasibility design (~45d)
   On Prudence Island, septic capacity is almost always the gating constraint, not zoning, because there is no public sewer anywhere on the island and most parcels share thin glacial-till soil. Engage an RI-licensed OWTS designer immediately to evaluate whether the existing field can absorb an ADU's added load, whether a conventional new field will fit, or whether an advanced-treatment system (typically $35,000 to $60,000 vs $20,000 to $30,000 conventional) is required. This step often kills marginal projects before any other money is spent.
2. Well capacity confirmation or new well drilling (~30d)
   No municipal water on Prudence Island; every parcel is served by a private well under RIDEM Office of Drinking Water rules. Confirm existing well yield can support the ADU or arrange a new drilled well. Brackish-water intrusion is documented in some shoreline areas and pre-drill water-quality testing is strongly recommended. Drilling rigs barge in from the Bristol mainland on the Bristol-Prudence ferry, which compresses summer scheduling.
3. Bay Islands Park / Prudence Conservancy easement check (~14d)
   Roughly 60 percent of Prudence Island is preserved land under the RIDEM Bay Islands Park system (created by the 1972 RI Bay Islands Park legislation) or under Prudence Conservancy easements. Confirm with both RIDEM Bay Islands Park staff and the Prudence Conservancy office that the parcel is not subject to a conservation easement that would foreclose ADU construction. The 2023 Map 84 Lot 60 rezoning from Open Space to R-20 (47,000 sqft minimum) is a useful precedent but does not generalize to other Open Space parcels.
4. Building permit submission via Portsmouth PermitLinkOnline (~5d)
   Prudence Island is part of the Town of Portsmouth and uses Portsmouth's e-permitting platform at permitlinkonline.com/csp/portsmouthri/DocumentLink. Upload stamped building plans, RIDEM OWTS approval, RIDEM Drinking Water well permit, CRMC approval (most Prudence shoreline parcels need it), and energy compliance forms. The portal routes to Portsmouth Building Inspection at 2200 East Main Road on the mainland.
5. Portsmouth building plan review (~35d)
   Portsmouth Building Inspection (401-683-3611) reviews IRC 2018 with RI amendments compliance for the Prudence parcel from the mainland office. Reviewers are familiar with Prudence-specific construction logistics (ferry-only material delivery, no hydrants on most of island, propane gas) and will flag plan items that won't survive island-only execution. Plan-check cycles average three rounds for Prudence parcels because of these unique constraints.
6. Prudence Island Volunteer Fire Department review (~14d)
   Prudence Island Volunteer Fire Department (292 Narragansett Avenue, all-volunteer staffing) reviews access and water-supply for new construction. Most of Prudence has no fire hydrants, so PIVFD evaluates whether a residential dry-hydrant or static water supply (cistern or pond access) will support fireground operations. PIVFD comments are sent back to Portsmouth Building Inspection on the mainland.
7. RIDEM OWTS and well permits issued (~30d)
   RIDEM issues the OWTS construction permit (state fee $350 to $1,200 depending on system type) and the Drinking Water well permit (state fee $200 to $500) on its own clock independent of Portsmouth's building permit. Both must be in hand before Portsmouth issues the building permit. RIDEM staff conduct a site visit on Prudence and ferry costs/scheduling factor into their availability.
8. Bristol-Prudence ferry vehicle scheduling (~21d)
   Material delivery to Prudence happens on the M/V Prudence, the Bristol-Prudence ferry from Bristol Town Wharf. Vehicle reservation slots, especially for full-size cement trucks, lumber trucks, and equipment trailers, are extremely limited May through October and must be booked weeks ahead. Single missed crossings ripple through the whole construction schedule. Plan to barge larger loads (concrete, modular sections) on Prudence Conservancy or commercial barges separately from the passenger ferry.
9. Construction inspections via ferry-borne inspector (~90d)
   Five inspection cycles (foundation, framing/MEP rough, insulation, MEP finals, overall final) but Portsmouth inspectors travel from the mainland Town Hall via the Bristol-Prudence ferry. Inspectors typically batch Prudence visits to one or two days per week, which extends each inspection cycle by an extra week or more compared to mainland Portsmouth. Weather cancellations of the ferry directly extend the construction critical path.
10. Certificate of Occupancy from Portsmouth (~7d)
    Once finals pass, Portsmouth Building Inspection at (401) 683-3611 issues the Certificate of Occupancy from the mainland office. Office hours: Monday through Wednesday 8:30 AM to 4:30 PM, Thursday 8:30 AM to 6:30 PM, Friday 8:30 AM to 2:30 PM at 2200 East Main Road, second floor.

• Long-term rental: yes Long-term rental permitted; small year-round population (~150) limits tenant pool.
• Short-term rental: with-restrictions Prudence summer-season demand exists (vacation rentals to Bristol/Portsmouth visitors who want car-free stays). Owner-occupancy of principal dwelling required per state ADU statute. Limited fire/EMS response time should be disclosed to renters.
• Office rental: with-restrictions Office rental impractical due to ferry commute; remote-work cabin viable.
• Home office: yes Owner home-office permitted; good remote-work environment.
• Studio / workshop: yes Personal artist/writer studio permitted; popular use case on Prudence.
• Agriculture: yes Large-lot R-20+ zones support agricultural accessory uses; existing small farms on Prudence.
• Relative support: yes Family-occupancy ADU permitted.

• Water: Private wells (no public water utility on Prudence) · 45d connect · $12,000
  No municipal water on Prudence Island. RIDEM Office of Drinking Water permit required for new wells. Brackish-water issues common in some areas; pre-drill water-quality tests recommended.
• Sewer: On-site wastewater treatment systems (septic) — no public sewer · 60d connect · $32,000
  Mandatory RIDEM OWTS permit and design by RI-licensed designer. Tight-soil parcels may require advanced-treatment system ($35-60k vs $20-30k for conventional). Adding ADU often requires field expansion or full new system.
• Electric: Rhode Island Energy (submarine cable from Bristol) · 30d connect · $4,500
  Power outages more frequent and longer on Prudence due to submarine-cable dependency.
• Gas: Propane (delivered by ferry) · 21d connect · $3,500
  No natural gas mains on Prudence. Propane tank installation only.

Realistic total: best 11mo · typical 17mo · worst 28mo

Prudence construction is dramatically slower: ferry-only material delivery, no on-island GCs, weather-dependent crossings, summer-season ferry vehicle space rationing, and septic/well drilling logistics extend timelines.

Modular pathway inspectors are novice with modular

State ADU loans:

• RIHousing financing

Few formal HOAs on Prudence. Private easements (Prudence Conservancy, RIDEM Bay Islands Park) function similarly and are not subject to HOA preemption.

• coastal-commission
  Prudence is entirely within CRMC jurisdiction (Narragansett Bay island). Most of the shoreline is regulated; ADUs near the water trigger CRMC Category B.
• wetland-overlay
  RIDEM Bay Islands Park system protects large preserved areas. Active enforcement of wetland buffers (50-200ft).
• flood-zone
  FEMA AE/VE zones along most of Prudence shoreline. Hurricane-vulnerable (sole evacuation route is ferry; effectively no evacuation in storms).
• other
  Prudence Conservancy / RIDEM Bay Islands Park easements cover ~60% of island. Confirm parcel is not subject to easement before acquisition.