| Max size | 800 sq ftgross living area above ground |
|---|---|
| Min size | 500 sq ftgross living area above ground |
| Bedrooms | Up to 2No cap stated for attached ADUs |
| Type | Attached + detachedDetached needs Planning Board CUP |
| Parking | No space count statedonly 'adequate parking' language |
| 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 Litchfield:
As of July 1, 2025, state law entitles you to build one detached ADU by right — the town cannot require a CUP hearing for it. Litchfield's ordinance (last touched in 2021) still requires a discretionary Conditional Use Permit from the Planning Board for a detached ADU, but that requirement is superseded.
State law gives you the choice of where your ADU's entrance goes. Litchfield's ordinance still flatly bans a front-facing secondary entrance, forcing it to the rear or side of the house — but the town can't dictate that anymore.
State law says the choice between a shared door and fully separate, independent access belongs to the homeowner, not the town. Litchfield's ordinance still mandates an internal door linking every attached ADU to the main house — no exceptions — but that mandate is superseded.
State law protects your right to separate electrical service for the ADU if you want it. Litchfield's ordinance still requires an attached ADU to run on the SAME utility service as the main house — no separate meter — but the town can't force that shared hookup.
State law entitles you to convert an existing structure into an ADU even if it's setback- or lot-coverage-nonconforming. Litchfield's ordinance doesn't explicitly say you can — a gap rather than a flat contradiction; worth confirming with the Building Inspector or an attorney before relying on it.
State law limits Litchfield to the same design standards it imposes on an ordinary home. Whether requiring your detached ADU to look like a garage or barn rather than a small house crosses into a stricter standard is a legal judgment call, not something this record can resolve.
Start with your rights under state law: since July 1, 2025, RSA 674:71-73 (as amended by HB 577) guarantees one ADU — attached or detached — by right in every district that allows single-family homes, with no Conditional Use Permit or board hearing, entrance and utility-service choices in the homeowner's hands, and protection for converting existing structures even where they're setback-nonconforming. Litchfield's ADU ordinance (Zoning §507.00, adopted March 13, 2012) has not been substantively updated since March 9, 2021 — the rest of the town's zoning document carries an 'Amended March 2024' cover date, but the ADU-specific sections were left untouched — so several of its provisions no longer hold up against your current rights: (1) the single biggest issue — a DETACHED ADU in Litchfield still requires a discretionary Conditional Use Permit from the Planning Board, not a by-right building permit, directly contradicting the state's mandate that one detached ADU be allowed by right in every district that allows single-family homes; (2) the town bars a front-door entrance for any 'secondary access,' forcing it to the rear or side of the house — state law says that choice is yours; (3) attached ADUs are required to have an internal connecting door to the main house — again, state law says the choice between a shared or fully separate entrance belongs to the homeowner; (4) attached ADUs must share the SAME utility service, house number, and mailbox as the primary dwelling — state law protects your right to separate electrical service; (5) there's no stated exemption letting you convert an existing nonconforming detached garage or barn into an ADU if it doesn't meet current setbacks, something state law explicitly guarantees. On the plus side, several things ARE compliant: the town's 500–800 sq ft ADU size range is lawful (a town's maximum cap simply may not be set below 750 sq ft, and Litchfield's 800 sq ft cap clears that; the 500 sq ft minimum is a town choice state law doesn't prohibit); owner-occupancy is required in either unit without specifying which (a rule towns may lawfully impose); and the detached-ADU two-bedroom cap is fine, since state law only bars limiting ADUs to one bedroom. Parking has no stated numeric requirement in the ADU section itself — just vague 'adequate parking' and 'maintains single-family appearance' language. The town also has a general Impact Fee Ordinance (Article 1300); whether it applies to ADUs is unconfirmed — ask the town. See conflicts[] for full citations; nothing in the ADU article has been updated for the 2025 state law, so where the two disagree, the state rule is the one you can rely on — confirm specifics with the Building Inspector before filing anything.
Get a free personalized report for your address in Litchfield — including where the 2025 law works in your favor.
Get My Free Litchfield ADU Report →House Bill 577 (2025) amended RSA 674:72, effective July 1, 2025. Wherever Litchfield's ordinance is stricter than this floor, the state law controls. Read the full NH ADU law explainer →
Yes — one accessory dwelling unit is allowed per single-family lot in Litchfield, and under state law that includes a detached ADU by right, even though the town's ordinance still demands a Conditional Use Permit hearing for detached units. 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.
800 sq ft — gross living area above ground. State law doesn't let any town cap ADU size below 750 sq ft.
Attached + detached (Detached needs Planning Board CUP). Since July 1, 2025, state law allows detached ADUs by right statewide — town provisions that prohibited them are superseded.
No space count stated — only 'adequate parking' language. 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.