New Haven ADU permit requirements
Last reviewed: June 22, 2026
Quick answer
Permitting an accessory dwelling unit (ADU) in New Haven, Connecticut means pulling a building permit from the local authority that issues it. ArchPermit tracks 14 source-cited requirements (10 required, the rest conditional) for this jurisdiction. Submittals go through City Squared online permit portal (paper not accepted). These requirements were last reviewed June 22, 2026; confirm the exact forms and fees with the local permitting authority.
A source-cited checklist of what an ADU (accessory dwelling unit) permit package needs in City of New Haven. Every item links to its authoritative source; items that vary are flagged to confirm locally.
ADUs are by-right (no special permit, no Site Plan review) in the RS-1, RS-2, RM-1, and RM-2 districts per Zoning Ordinance Section 22 (Ord. 1918, eff Oct 2021); a special exception is needed only if the ADU would push the lot above four units. Owner-occupancy is mandatory (a notarized Affidavit of Residence), and a recorded deed restriction (owner-occupancy, no separate sale, runs with the land) must be filed before the building permit issues. ADU min livable area 400 sf, max gross floor area 1,200 sf or the size of the principal dwelling (smaller); min lot 4,000 sf; no minimum off-street parking. Phase 1 ordinance limits creation to existing principal/accessory structures (a Phase 2/3 expansion was pending, not confirmed enacted). New Haven relies on its own Section 22 ordinance rather than the CT PA 21-29 default.
- Affidavit of Residence (Owner Occupancy), notarizedrequired
Signed, notarized ADU Affidavit of Residence per the Owner Occupancy & Leave of Absence rules; submitted to the City Clerk.
source · reviewed 2026-06-22 - Building Permit Application (via City Squared)required
Complete the building permit in City Squared with a detailed project description, any off-street parking used for the ADU, and the property owner's original signature.
source · reviewed 2026-06-22 - Deed Restriction (recorded)required
Signed/notarized ADU deed restriction filed with the City Clerk's Office of Land Records; provide a copy of the recorded restriction with the application.
source · reviewed 2026-06-22 - Elevationsrequired
Proposed elevations of all sides of the structure(s) associated with the improvements.
source · reviewed 2026-06-22 - Floor Plansrequired
Every floor associated with the improvements; sheets ≥8.5×11, scale ≥1"=16 ft if scaled, every room labeled.
source · reviewed 2026-06-22 - Photographsrequired
Color photos of front, sides, and rear of the existing property (≥8×10, individually labeled with location + proposed work).
source · reviewed 2026-06-22 - Plot Planrequired
Building envelope of all structures, property line, and proposed + required setbacks (sheets ≥8.5×11, scale ≥1"=16 ft).
source · reviewed 2026-06-22 - Regional Water Authority Consumption Billrequired
A copy of the South Central CT Regional Water Authority consumption bill (adequate water supply).
source · reviewed 2026-06-22 - Sanitary Sewer Permit + Approved Stamped GNHWPCA Plansrequired
A copy of the Sanitary Sewer Permit and the approved, stamped Greater New Haven Water Pollution Control Authority plans (adequate sewer).
source · reviewed 2026-06-22 - Zoning Tablerequired
Completed using the City's required format (heights, coverage %, gross floor area, lot width, setbacks, parking).
source · reviewed 2026-06-22 - ADU Application Compliance Review Sheetconditionalverify locally
A pre-submission compliance document (owner on-site; no open Building/Fire/Housing violations; adequate water/sewer) referenced by the checklist.
source · reviewed 2026-06-22 - Certificate of Occupancy / Certificate of Approvalconditional
Post-construction, after inspections: a new CO when the use changes (adding a unit), otherwise a Certificate of Approval.
source · reviewed 2026-06-22 - Historic District Certificate of Appropriatenessconditional
Required only if the property is in a Local Historic District and the ADU is visible from a public way.
source · reviewed 2026-06-22 - Survey (signed & sealed)conditional
NOT required for ADUs in existing structures; if provided, must be signed/sealed with the survey date (scale ≥1"=30 ft).
source · reviewed 2026-06-22