City guide · New Britain, Connecticut

New Britain ADU regulations.

ADU zoning guide for New Britain, CT. Learn about permitted ADU types, size limits, parking rules, and owner occupancy requirements.

Last reviewed 2026-04-27

  • ADUs allowedYes — under Chapter 25 of the New Britain Code of Ordinances, adopted December 15, 2022
  • ApprovalZoning + building permit through the New Britain Building / Zoning Department
  • Owner occupancyRequired

New Britain, CT permits Accessory Dwelling Units under Chapter 25 of its Code of Ordinances, adopted December 15, 2022. The local rules are more restrictive than the CT state baseline: ADUs are limited to 800 sq ft (or 40% of the principal-structure floor area, whichever is less), must be attached to the primary residence, require owner-occupancy, and need 3 off-street parking spaces total. The CT Affordable Homes Act 2024 (effective February 2025) may have preempted some local provisions — confirm with Planning & Zoning before starting any project.

Status

Currently allowed
Yes — under Chapter 25 of the New Britain Code of Ordinances, adopted December 15, 2022
Form of approval
Zoning + building permit through the New Britain Building / Zoning Department; specific procedure per Chapter 25
Governing ordinance section
New Britain Code of Ordinances, Chapter 25 — Accessory Dwelling Units
Last amended
Chapter 25 adopted December 15, 2022

Eligibility

Where ADUs are allowed

Zoning districts permitted
Single-family residential zones, with a minimum lot size requirement
Minimum lot area
8,000 sq ft (the lot itself must exceed 8,000 sq ft for an ADU per Chapter 25)
Limit per property
1 ADU per lot
Lot type / use restrictions
Single-family residence; the principal owner must claim one of the units as a primary residence

Types allowed

Attached ADU (interior conversion or addition)
Yes — only attached forms permitted under Chapter 25
Detached ADU (free-standing)
No — detached ADUs are not permitted in New Britain
Garage conversion
Conditional — only if attached to or within the principal structure

Size and placement

Size limits

Maximum size
800 sq ft OR 40% of the principal-structure floor area, whichever is LESS
Self-contained requirement
Each ADU must have separate cooking, sanitary, and sleeping facilities

Setbacks

Setback requirements
Must comply with existing zone setback standards; CT framework prohibits more restrictive ADU-specific setbacks
S-2 zone dimensional standards
Minimum lot area: 8,000 sq ft

Rules for use

Parking

Required spaces
3 off-street parking spaces total (2 for the principal dwelling + 1 for the ADU)
Curb cuts
No new curb cuts allowed — the existing driveway must serve both units

Owner occupancy

Required
Yes — per Chapter 25, no owner may construct or maintain an ADU without claiming one of the units (primary or ADU) as their primary residence
Post-2024 state-law caveat
CT Affordable Homes Act 2024 (PA 24-148, effective February 2025) removes municipal authority to require owner-occupancy in many ADU contexts. Whether New Britain has amended Chapter 25 to comply is unclear.

Rental use

Long-term rental
Permitted
Short-term rental
Not addressed in retrieved Chapter 25 excerpts — confirm with Building/Zoning

How to apply in New Britain

Approving body
New Britain Building / Zoning Department
Application requirements
Architectural drawings, site plan demonstrating lot size and parking
Utilities requirement
Existing utility connections must serve the ADU (no separate hookups)
Contact
New Britain Planning & Zoning Department | newbritainct.gov | (860) 826-3375

Recent and pending changes

  1. December 15, 2022
    Mayor Stewart and the Common Council adopted Chapter 25 of the Code of Ordinances, governing Accessory Dwelling Units.
  2. February 2025
    CT Affordable Homes Act 2024 (PA 24-148) takes effect statewide. May preempt Chapter 25 owner-occupancy and lot-size requirements.

Important details

  • Chapter 25 caps ADUs at 800 sq ft OR 40% of the principal-structure floor area — whichever is LESS. This is more restrictive than the CT state baseline (1,000 sq ft / 30%).
  • Detached ADUs are not permitted — only attached forms (interior conversion or wall-shared addition).
  • Three off-street parking spaces are required total. New curb cuts are prohibited.
  • Minimum lot size of 8,000 sq ft applies to ADU eligibility.

Frequently asked questions

Does New Britain follow the state ADU law or have custom regulations?

New Britain has not opted out of Public Act 21-29, so the city follows the state's default ADU regulations rather than creating its own stricter rules.

What are the size and type requirements for ADUs in New Britain?

ADUs can be attached or detached with a maximum size of 1,000 square feet or 30 percent of the square footage of the primary dwelling, whichever is less, as set by Connecticut state law.

Can New Britain impose additional parking requirements beyond the state standard?

No, under Public Act 21-29, towns cannot require more than one parking space per ADU, and New Britain must comply with this state-mandated maximum.

Sources (4)

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Last reviewed 2026-04-27. Local rules can change — verify the latest details with the New Britain planning department, or book a free consultation with our team before starting your project. This page is informational and is not legal advice.