Building an ADU in Meredith, NH: The 2026 Deep Dive

Yes — you can build one accessory dwelling unit (ADU) on your single-family property in Meredith, New Hampshire, and since July 1, 2025 you can do it by right under state law (RSA 674:72, amended by House Bill 577, 2025 Chapter 197). You would never guess that from Meredith's zoning ordinance, which still calls the unit an "Accessory Apartment" and requires a Special Exception hearing before the Zoning Board of Adjustment — a hearing state law no longer lets the town demand for your one by-right ADU.

That gap between the ordinance on paper and the law that actually controls is the whole story in Meredith. This guide covers the history, the current rules (confirmed with the town), the conflicts, and the permit path — the Lakes Region deep dive.

Does Meredith allow ADUs in 2026?

One ADU per lot, attached or detached, anywhere single-family homes are allowed. But Meredith's district use tables tell an older story: "Accessory Apartments" appear under the Special Exceptions column — never the Permitted Uses column — in every district that allows single-family dwellings, from the Residential and Shoreline districts to Forestry & Conservation and the commercial districts along Route 3.

Under the ordinance as written, every accessory apartment means a Zoning Board of Adjustment hearing. Under RSA 674:72, effective July 1, 2025, that hearing requirement is superseded: one ADU is a matter of right, with no special exception, variance, or conditional-use permit for the ADU itself. A normal building permit and reasonable local standards — setbacks, lot coverage, septic, building and fire code — still apply. The full statewide picture is in our NH ADU law guide.

Why does Meredith's ordinance still say "Special Exception"?

History explains it. Meredith's accessory apartment section (Article III, Section N) was last substantively amended on March 11, 2008 — the ordinance cover is dated March 14, 2023, but the ADU rules themselves have sat unchanged for the better part of two decades. Nothing in the accessory-apartment provisions, the use tables, or the definitions references the 2025 state law.

That makes Meredith a textbook example of a statewide pattern: many towns' posted ordinances still contain language the state law now overrides. It doesn't mean the town is hostile to ADUs. It means the rulebook at the counter predates the law that now controls, and a homeowner who takes the PDF at face value will believe they need a hearing they're no longer required to attend.

What are Meredith's actual ADU rules right now?

The numbers below come from the town's ordinance and were confirmed with the town's planning staff:

• How many: one accessory apartment per lot.
• Size: minimum 300 sq ft of net floor area; maximum is the lesser of 40% of the combined net floor area of the main home plus the apartment, or 1,200 sq ft. On most homes that lands well above the state's 750 sq ft protected floor — see the conflict note below for small homes.
• Bedrooms: no more than two.
• Owner occupancy: required — the owner must live in either the main home or the apartment, and the town does not dictate which. That matches what state law allows: a town may require owner-occupancy of the property, but the owner picks the unit.
• Parking: one space for the accessory apartment (on top of two for the main residence), surfaced consistent with the neighborhood and outside the front setback.
• Impact fees: none for an accessory apartment, per the town.
• Setbacks: set by district, not by the ADU rules. In the Residential District (non-waterfront), figures confirmed with the town are 30 ft front, 20 ft side, 40 ft rear; in Forestry/Rural (non-waterfront), 40 ft front and rear, 30 ft sides — waterfront lots run tighter or different, so check your zone.
• Smoke alarms: per town staff, alarms must be hard-wired and interconnected with the main house if the ADU sits within 30 feet of it; beyond 30 feet, a wireless interconnection suffices.

Notably absent: no familial-relationship requirement, no ban on a separate entrance, and no one-bedroom limit. Where the ordinance is silent, the homeowner's state-law rights simply stand.

Can you build a detached ADU in Meredith?

Under state law, yes — the by-right guarantee covers attached and detached units. Meredith's ordinance, though, attaches strings the state guarantee doesn't carry. As written, a detached accessory apartment must sit inside an accessory structure that also serves another accessory use (a garage or workshop — the building can't exist solely as housing), must be within 150 feet of the main home's living space, and still needs the Special Exception.

The hearing requirement and the "double duty" structure condition are more restrictive than the state's unconditional detached-by-right rule, and state law controls where they conflict. The 150-foot limit is murkier: on Meredith's large rural lots — Forestry & Conservation requires 10-acre minimums — a barn or garage past that line could be blocked as an ADU site under the town's text, and whether that dimensional rule survives the 2025 law is a genuine attorney question, not a settled one.

One more state-law protection worth knowing: converting an existing garage to an ADU is allowed even if the garage doesn't meet current setbacks. Meredith's ordinance contains no such exemption in writing — another spot where the state rule fills the gap.

Where exactly does the ordinance conflict with state law?

• Special Exception requirement — superseded. Your one ADU is by right; no ZBA hearing.
• Detached-unit conditions — the hearing and the requirement that the structure house another accessory use are superseded; the 150-ft distance limit is unresolved and worth a land-use attorney's read.
• The 40% size formula — on a smaller principal home, 40% of the combined floor area can compute to less than the 750 sq ft floor state law protects. How the town would apply it is untested; treat this as a case-by-case check.
• Parking location — the one required ADU space matches the state's cap, but the ordinance reads as on-site only. State law lets the owner choose a legally dedicated off-site space instead.

How do you actually get an ADU permit in Meredith?

1. Confirm your district and setbacks. Start with our Meredith town guide and the town's dimensional table for your zone — waterfront status matters here.
2. Design inside the clear numbers. 300–1,200 sq ft (watch the 40% formula), two bedrooms max, one parking space.
3. Check septic capacity early. A second dwelling unit has to be supported by your septic system or sewer connection — on Lakes Region lots this is often the real constraint, not zoning.
4. Apply for a standard building permit. If you're told an accessory apartment needs a Special Exception, politely point to RSA 674:72, effective July 1, 2025. Your one ADU does not require a hearing.
5. Build to code, including the smoke-alarm interconnection rule for units near the main house.

For budgeting, a typical New Hampshire ADU build runs $275,000–$400,000+ depending on design — and if the unit keeps a parent out of assisted living, which commonly cited industry surveys put at $70,000–$100,000+ per year in NH, the math gets compelling fast. Our guides cover costs and financing in depth, and you can compare Meredith against its neighbors in our Belknap County guide.

Meredith's rulebook is stuck in 2008 — your building rights are not.