Portsmouth

1. Zoning district and easement screening (~5d)
   Confirm the parcel's zoning district at Portsmouth Town Hall, 2200 East Main Road (R-10, R-20, R-40, R-60, or R-80 — Portsmouth uses unusually large minimum lot sizes in its R-60 and R-80 districts because of Aquidneck Island septic-density planning). Check whether the parcel carries an Aquidneck Land Trust conservation easement, which is common around Bristol Ferry Road and Common Fence Point and can override otherwise by-right ADU rights. Portsmouth Tax Assessor maintains parcel records that flag ALT easements.
2. Water-service authority determination (~7d)
   Portsmouth has a split water-service map: most of the town is served by Portsmouth Water and Fire District (PWFD, chartered 1952 by RI General Assembly as a quasi-municipal agency, governed by a 7-member elected Administrative Board, 132 miles of main and 4 storage tanks, buying wholesale from Newport Water). The southwest corner — Redwood Farms, Bay View Condos, Raytheon facility, Melville Navy Housing, and the Navy Base — is served directly by Newport Water Division, not PWFD. Confirm provider and availability of an ADU service tap before drawing plans, because PWFD's connection lead time is materially different from Newport Water's.
3. RIDEM OWTS septic design (most parcels) (~45d)
   Most of Portsmouth is on private septic, not municipal sewer, so adding an ADU normally requires a Rhode Island Department of Environmental Management Onsite Wastewater Treatment System review. Engage an RI-licensed OWTS designer to confirm whether the existing field can absorb the additional load or whether a new field or advanced-treatment system is required. RIDEM OWTS permit issuance runs 30 to 60 days from a complete submission and is a separate state-level process from the town building permit.
4. CRMC assent (if coastal) (~90d)
   Mount Hope Bay shoreline (Bristol Ferry Road, Common Fence Point causeway), Sakonnet River frontage (east-side parcels), and Hummocks Park area parcels within 200 ft of mean high water trigger CRMC Category A or B assent. Common Fence Point causeway parcels are in FEMA V zones and additionally need a coastal-construction control line analysis. CRMC review averages 60 to 120 days running concurrent with town building permit.
5. Building permit submission via PermitLinkOnline (~3d)
   Portsmouth uses the PermitLinkOnline e-permitting platform at permitlinkonline.com/csp/portsmouthri/DocumentLink. Upload stamped building plans, site plan, RIDEM OWTS approval (if applicable), CRMC approval (if applicable), and energy compliance forms. The portal routes the application to Portsmouth Building Inspection at 2200 East Main Road, second floor.
6. Building plan review and Fire Department review (~25d)
   Portsmouth Building Inspection (401-683-3611) reviews IRC 2018 with RI amendments compliance. Portsmouth Fire Department conducts a new-construction plan review with a $75 fee covering hydrant access, knox-box requirements, and (for coastal Common Fence Point parcels) the longer engine response time from the Hummocks station. Plan check averages two cycles for non-overlay parcels.
7. Permit fee payment under valuation formula (~1d)
   Portsmouth charges $14 per $1,000 of construction valuation with a $50 minimum, plus the $75 Fire Department plan review fee, plus separate plumbing, electrical, and mechanical permits. Total permit-fee bundle for a typical Portsmouth ADU runs $1,200 to $3,000 depending on valuation. RIDEM OWTS permit ($350 to $1,200) is paid separately to the state.
8. Construction inspections (~45d)
   Five inspection cycles: foundation, framing/MEP rough-in, insulation, MEP finals, overall final. Portsmouth inspectors dispatch from Town Hall second floor; lead time is generally one to three days for routine inspections but stretches in summer. CRMC and OWTS-required final certifications are submitted alongside the building final.
9. Certificate of Occupancy issuance (~5d)
   Once all finals pass, Portsmouth Building Inspection issues the Certificate of Occupancy. Office hours are Monday through Wednesday 8:30 AM to 4:30 PM, Thursday 8:30 AM to 6:30 PM, and Friday 8:30 AM to 2:30 PM at 2200 East Main Road, second floor. Phone: (401) 683-3611.

• Long-term rental: yes Long-term rental is the by-right baseline use under R.I.G.L. § 45-24-37(j).
• Short-term rental: with-restrictions Portsmouth STR rules less restrictive than Newport City but Town requires registration. Owner-occupancy of principal dwelling required for ADU-as-STR per state ADU statute.
• Office rental: with-restrictions Renting ADU as office requires home occupation review.
• Home office: yes Owner home-office use is permitted accessory use.
• Studio / workshop: yes Personal studio / workshop permitted.
• Agriculture: yes Portsmouth's R-60/R-80 large-lot zones explicitly permit agricultural accessory uses; the town has active farms (Sweet Berry, Aquidneck Farms).
• Relative support: yes Family-occupancy ADU explicitly permitted.

• Water: Portsmouth Water and Fire District (most of town) / Newport Water (SW corner) · 30d connect · $5,200
  PWFD chartered 1952, governed by 7-member elected Administrative Board, 132 miles of main, 4 storage tanks, 2 pumping stations. Buys wholesale from Newport Water (9 reservoirs). SW corner of Portsmouth (Redwood Farms, Bay View Condos, Raytheon, Melville Navy Housing, Navy Base) is served directly by Newport Water — confirm provider before applying.
• Sewer: Mostly on-site septic; limited municipal sewer · 14d connect · $18,000
  Most of Portsmouth uses on-site wastewater treatment systems (OWTS / septic). RIDEM OWTS permit required for ADU on septic. Connection cost reflects new septic field for ADU; tie-in to existing septic possible only if capacity allows per RIDEM design.
• Electric: Rhode Island Energy · 21d connect · $1,800
• Gas: Rhode Island Energy (limited gas service in Portsmouth; many parcels are propane or oil) · 30d connect · $2,500

Realistic total: best 7mo · typical 11mo · worst 17mo

Portsmouth contractor lead times less constrained than Newport City because no historic-district seasonality. Septic-system design adds 4-8 weeks for parcels not on PWFD-served sewer.

Modular pathway inspectors are occasional with modular

State ADU loans:

• RIHousing financing

R.I.G.L. § 45-24-73 voids HOA / condo restrictions conflicting with state ADU minimums. Portsmouth HOA prevalence is moderate, concentrated in Carnegie Abbey, Common Fence Point Cooperative, and Aquidneck Land Trust easement parcels.

• coastal-commission
  RI CRMC jurisdiction within 200ft of coastal feature. Mt. Hope Bay, Sakonnet River shoreline, Bristol Ferry, Common Fence Point all trigger CRMC Category A or B review.
• wetland-overlay
  RIDEM Freshwater Wetland buffer (50-200ft depending on wetland type) common in Portsmouth's interior parcels. RIDEM permit required for work within buffer.
• flood-zone
  FEMA AE/VE zones along Mt. Hope Bay shoreline and Sakonnet River. Common Fence Point causeway parcels are in V zones.