ADU Rules in Chester, New Hampshire
Rockingham County · Reconciled with the 2025 state law · Last reviewed 2026-10-26
Allowed by rightReconciled with the 2025 state law✓ Verified by a real human here in NH · July 30, 2026
The short answer
Yes — Chester allows one ADU (verified with the town), up to 1,000 sq ft.
Chester ADU rules at a glance
| Max size | 1,000 sq ftconfirmed with the town |
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| Min size | 600 sq ftconfirmed with the town |
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| Bedrooms | Up to 2confirmed with the town |
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| Type | Attached or detacheddetached: at least 15 ft from the house |
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| Parking | 1 spot on siteconfirmed with the town |
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| Owner-occupancy | Requiredin either the ADU or the primary home |
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| Short-term rental | Not statednot addressed in the ordinance |
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| Utility connection | Tie into the existing electrical connection or choose a separate metersame statewide |
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About minimum size: Chester does set its own minimum ADU size — see the Min size row above. That's a town choice, not a state requirement: state law only limits how small a town may set its maximum (never below 750 sq ft).
The full plain-English rundown
CONFIRMED WITH THE TOWN (July 30, 2026) — ADUs allowed: 1; maximum size 1,000 sq ft; minimum size 600 sq ft; up to 2 bedrooms; impact fees: Yes based off of SqFt, along with additional fees not specified.; parking: 1 spot on site; detached-unit distance rule: No closer than 15'; setbacks: 40' Front, 25' sides and rear, 75' from wetlands. Town contact: Michael Cumings - Building Inspector.
ADUs shall not be constructed on land that is leased or rented.
Pat called and spoke with the Building inspector-Information updated
What does this mean for YOUR property?
Get a free personalized report for your address in Chester — including where the 2025 law works in your favor.
Get My Free Chester ADU Report →What New Hampshire law guarantees in every town
House Bill 577 (2025) amended RSA 674:72, effective July 1, 2025. Wherever Chester's ordinance
is stricter than this floor, the state law controls. Read the full NH ADU law explainer →
One ADU by rightEvery single-family lot in New Hampshire may add one accessory dwelling unit — attached or detached — as a matter of right. No special exception, variance, or conditional-use permit can be required for the ADU itself.
At least 750 sq ftA town may cap ADU size, but the cap can't be lower than 750 sq ft. (That's a ceiling on how strict a town can be — not a minimum you have to build.)
At most 1 extra parking spaceA town can require no more than one additional parking space for an ADU, and the owner chooses whether it's on-site or off-site.
No family-only ruleTowns can no longer require the ADU occupant to be related to you.
More than one bedroomA town can't limit an ADU to a single bedroom.
Separate utilities allowedA town can't force the ADU to share the main home's electrical service — a separate connection or meter is your choice.
Garage conversions protectedConverting an existing garage to an ADU is allowed even if the garage doesn't meet today's setbacks.
Owner-occupancy, either unitA town may require the owner to live on the property, but the owner picks which unit — the main home or the ADU.
Chester ADU questions, answered
Can I build an ADU in Chester, NH?
Yes — Chester allows one ADU (verified with the town), up to 1,000 sq ft. 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.
How big can an ADU be in Chester?
1,000 sq ft — confirmed with the town. State law doesn't let any town cap ADU size below 750 sq ft.
Can I build a detached ADU in Chester?
Attached or detached (detached: at least 15 ft from the house). Since July 1, 2025, state law allows detached ADUs by right statewide — town provisions that prohibited them are superseded.
Does Chester require extra parking for an ADU?
1 spot on site — confirmed with the town. State law caps what any town can require at one additional space, located on- or off-site at the owner's choice.
Do I have to live on the property to have an ADU in Chester?
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.
These are Chester's town-wide ADU standards under the 2025 state law — confirm your
parcel's specific zoning district with the town, since a few districts can differ. This guide is an
independent informational resource, not legal advice; verify with Chester's planning department
before you build.