ADU Rules in Laconia, New Hampshire
Belknap County · Reconciled with the 2025 state law · Last reviewed 2026-09-10
Allowed by rightReconciled with the 2025 state law✓ Verified by a real human here in NH · 08/11/26
The short answer
Yes — Laconia allows one ADU (verified with the town), up to 1,000 sq ft.
Laconia ADU rules at a glance
| Max size | 1,000 sq ftconfirmed with the town |
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| Min size | 300 sq ftconfirmed with the town |
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| Bedrooms | No regulationsconfirmed with the town |
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| Type | Not statednot addressed in the ordinance |
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| Parking | 1 Spot for ADUconfirmed 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: Laconia 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 (08/11/26) — ADUs allowed: 1; maximum size 1,000 sq ft; minimum size 300 sq ft; up to No regulations bedrooms; impact fees: No for ADU; parking: 1 Spot for ADU; detached-unit distance rule: No; setbacks: Most Common Zone is Residential General (RG) and Residential single-Family(RS). Setbacks are 25' Front 10' Side and 15' Rear. Town contact: Rob Mora - Planning Director (603) 527-1264.
If the primary unit is greater than 4,000 square feet, the ADU must not exceed 25% of the gross living area of the primary unit.
No requirement for smoke alarms to be hardwired into main house. Bluetooth would suffice.
What does this mean for YOUR property?
Get a free personalized report for your address in Laconia — including where the 2025 law works in your favor.
Get My Free Laconia ADU Report →What New Hampshire law guarantees in every town
House Bill 577 (2025) amended RSA 674:72, effective July 1, 2025. Wherever Laconia'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.
Laconia ADU questions, answered
Can I build an ADU in Laconia, NH?
Yes — Laconia 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 Laconia?
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 Laconia?
Since July 1, 2025, state law allows detached ADUs by right statewide — town provisions that prohibited them are superseded.
Does Laconia require extra parking for an ADU?
1 Spot for ADU — 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 Laconia?
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 Laconia'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 Laconia's planning department
before you build.