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New Britain, CT Accessory Structures: ADU Rules (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

ADU rules in New Britain, CT, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.

Key Facts

Construction delay
24 months after new single-family home in S-1/S-2/S-3
Delay exemption
Rebuilds after fire, flood, or other disaster
Utility rule
Must use property's existing water, gas, electric service
Adopted
Resolution No. 35885-2, December 19, 2022
Amended
Resolution No. 36574-2, October 3, 2024
Governing sections
Code of Ordinances Sections 25-2 and 25-3

Summary

New Britain's accessory dwelling unit chapter bars building an ADU within twenty-four months of a new single-family home in the S-1, S-2, and S-3 districts, unless the home was rebuilt after a fire, flood, or other disaster. Code of Ordinances Section 25-3 also requires every ADU to run on the parcel's existing water, gas, and electric connections.

No owner of a property, in the S-1, S-2, and S-3 district shall construct an accessory dwelling unit within twenty-four (24) months of a new construction single-family home on the same parcel. Replacement of a building destroyed by fire, flood, natural disaster, or other "act of god" that previously housed an accessory dwelling unit shall be exempt from requirement. ... Any and all accessory dwelling units must use existing utility connections, including, but not limited to, water, gas, and electric service.

Full Breakdown

New Britain added a dedicated accessory dwelling unit chapter, Chapter 25 of the Code of Ordinances, by Resolution No. 35885-2 on December 19, 2022, later amended by Resolution No. 36574-2 on October 3, 2024. Section 25-2's new construction delay requirement stops an owner in the S-1, S-2, or S-3 single-family zoning districts from building an accessory dwelling unit within twenty-four months of putting up a new single-family home on the same lot, a timing rule aimed at preventing a home and its ADU from being built together as a de facto duplex.

The delay does not apply when the home being replaced was destroyed by fire, flood, a natural disaster, or another act deemed an act of God and had already housed an ADU. Section 25-3 adds an infrastructure condition that applies citywide: an accessory dwelling unit must tie into the utility connections already serving the property, including water, gas, and electric service, rather than obtaining new, separate utility connections. Together with the ownership and occupancy statute in Section 25-1, these three sections make up New Britain's full ADU framework, covering timing, utilities, and occupancy.

The zoning department administers compliance, and because Section 25-1 conditions the certificate of occupancy on a signed, notarized affidavit, utility hookups and construction timing are effectively checked before a new ADU can be occupied.

Violations & Fines

Sections 25-2 and 25-3 do not carry their own fine schedule. The only enforcement clause in Chapter 25 appears in Section 25-1: an owner who fails to prove continued occupancy of one unit on the parcel faces enforcement action, including fines and a demolition order for the accessory dwelling unit. Compliance with the construction-delay and utility rules is confirmed through the same certificate-of-occupancy and annual-affidavit process the zoning department uses to police occupancy.

Frequently Asked Questions

How soon after building a new house can I add an ADU in New Britain?
In the S-1, S-2, and S-3 single-family districts, Code of Ordinances Section 25-2 requires a wait of twenty-four months after completing a new single-family home before you can build an accessory dwelling unit on the same lot. The wait does not apply if the home you are replacing was destroyed by fire, flood, or another disaster and had already housed an ADU.
Can my New Britain ADU have its own water and electric meter?
No. Section 25-3 requires every accessory dwelling unit to use the property's existing utility connections, including water, gas, and electric service, rather than installing new, separate hookups. This keeps ADUs tied to the main house's service rather than functioning as a fully independent utility account.
What happens if I build an ADU too soon after new construction?
Chapter 25 does not list a separate fine for jumping the twenty-four-month window in Section 25-2. The zoning department checks timing and utility compliance through the same certificate-of-occupancy and annual-affidavit process required under Section 25-1, so a premature or improperly connected ADU can hold up that sign-off before enforcement under Section 25-1 applies.

Sources & Official References

Other rules in New Britain

All New Britain rules

How New Britain compares: Easiest Cities to Build an ADU·Compare New Britain to another location·View the Connecticut accessory structures overview

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