| Max size | 1,000 sq ft attached750 sq ft if detached |
|---|---|
| Min size | No town minimumbuild as small as code allows |
| Bedrooms | Up to 2 |
| Type | Attached or detachedby right in every district |
| Parking | 1 off-street spacededicated to the ADU |
| Owner-occupancy | Requiredin either the ADU or the primary home |
| Short-term rental | Not stated |
| Utility connection | Tie into the existing electrical connection or choose a separate metersame statewide |
The July 2025 state law (RSA 674:71–73) overrides local ordinance language that conflicts with it — even language a town still has posted. Here's what that means in Barrington:
Barrington's ordinance requires electric, water, and sewer to be on one combined bill for the whole property. Since July 2025, state law gives you the right to a separate electrical panel/service for your ADU if you want one — the town cannot force a single shared electric meter.
Barrington's ordinance mandates a connecting interior door between an attached ADU and the main house. State law says you get to choose independent (fully separate, no interior connection required) or shared access for an attached ADU — the town can't force the interior-door design.
Barrington can only hold your ADU to the same design rules it holds an ordinary house to — not stricter 'don't-look-like-two-families' standards. Whether this clause crosses that line is an attorney call.
Barrington's text reads as if the extra parking space must be on your own lot. State law gives you the choice — on-site or a legally dedicated off-site spot — not the town.
Every time a Barrington property with an ADU changes hands, the new owner has to re-apply (and pay a fee) for an ADU Certificate of Use just to keep renting it out. Whether this recurring administrative/fee burden is 'a requirement beyond those for a single-family dwelling' that HB 577 bars is not settled — worth a local attorney's opinion.
Barrington's own posted ordinance is written to the pre-2025 version of state law. Anywhere the posted text is silent on or more restrictive than the new 2025 rules, the new state law controls — the town just hasn't rewritten its ordinance yet to say so.
Barrington's zoning ordinance (Article 3, Section 3.5, as amended 3/11/2025) permits one Accessory Dwelling Unit (ADU) as a permitted, by-right use in every zoning district in town — General Residential, Neighborhood Residential, Village, Town Center, Regional Commercial, and the Highway Commercial Overlay. You do not need a special exception, conditional use permit, or Planning Board hearing; you need a building permit and an administrative 'Certificate of Use' from the Zoning Administrator. The ADU can be attached to, within, or fully detached from your single-family home (including new construction of a detached accessory structure). Size caps: up to 1,000 sq ft if attached/within the home, or 750 sq ft finished floor if detached. It can have up to two bedrooms, and you (the owner) must live in one of the two units — the ordinance doesn't say which one, matching state law. Where Barrington's posted rules fall short of your rights under the July 2025 state law update (HB 577): (1) the town says electric, water, and sewer must be on one combined bill — but state law gives you the right to a separate electrical panel/service for the ADU if you want one; (2) the town requires an interior door connecting an attached ADU to the main house — but state law says you get to choose a fully independent entrance instead; (3) the town's 'must fit aesthetically' design clause may go beyond what the town can require of any single-family home; (4) the ordinance implies the required parking space must be on your own lot, when state law lets you choose an off-site legally dedicated space instead; and (5) the town requires a brand-new ADU Certificate of Use (with a fee) every time the property changes hands, which is a heavier burden than an ordinary house faces on resale. Bottom line: Barrington is broadly ADU-friendly and byright, but its ordinance was last amended before HB 577 took effect and hasn't caught up on several homeowner-favorable details.
Primary source: Town zoning ordinance (PDF) — Zoning Ordinance 'As Amended March 11, 2025' (cover page…
Get a free personalized report for your address in Barrington — including where the 2025 law works in your favor.
Get My Free Barrington ADU Report →House Bill 577 (2025) amended RSA 674:72, effective July 1, 2025. Wherever Barrington's ordinance is stricter than this floor, the state law controls. Read the full NH ADU law explainer →
Yes — Barrington allows one accessory dwelling unit (attached or detached) by right in every zoning district. Under RSA 674:72 (as amended effective July 1, 2025), one accessory dwelling unit — attached or detached — is allowed by right on single-family lots statewide.
1,000 sq ft attached — 750 sq ft if detached. State law doesn't let any town cap ADU size below 750 sq ft.
Attached or detached (by right in every district). Since July 1, 2025, state law allows detached ADUs by right statewide — town provisions that prohibited them are superseded.
1 off-street space — dedicated to the ADU. State law caps what any town can require at one additional space, located on- or off-site at the owner's choice.
Required — in either the ADU or the primary home. Where owner-occupancy is required, state law lets the owner choose which unit to live in.