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CHAPTER 210
HB 1079 - FINAL VERSION
11Mar2026... 0823h
05/07/2026 1710s
2026 SESSION
26-2594
04/09
HOUSE BILL
1079
AN ACT
allowing accessory dwelling units to be built within or attached to certain non-conforming structures.
SPONSORS: Rep. Howland, Straf. 20; Rep. D. Paige, Carr. 1; Rep. Preece, Hills. 17
COMMITTEE: Housing
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ANALYSIS
This bill expands the definition of accessory dwelling units to allow them to be built within nonconforming structures.
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Explanation: Matter added to current law appears in
bold italics.
Matter removed from current law appears [
in brackets and struckthrough.
]
Matter which is either (a) all new or (b) repealed and reenacted appears in regular type.
11Mar2026... 0823h
05/07/2026 1710s 26-2594
04/09
STATE OF NEW HAMPSHIRE
In the Year of Our Lord Two Thousand Twenty-Six
AN ACT
allowing accessory dwelling units to be built within or attached to certain non-conforming structures.
Be it Enacted by the Senate and House of Representatives in General Court convened:
210:1 Accessory Dwelling Unit; Definition. Amend RSA 674:71, II-III to read as follows:
II. "Attached unit" means a unit that is within or [
physically connected
]
attached
to the principal dwelling unit[
, or completely contained within a preexisting detached structure
].
III. "Detached unit" means a unit that is neither within nor physically connected to the principal dwelling unit[
, nor completely contained within a preexisting detached structure
].
210:2 Accessory Dwelling Unit; Existing Structures. Amend RSA 674:72, XI to read as follows:
XI. A municipality shall allow accessory dwelling units to be converted from existing structures, including but not limited to detached garages, regardless of whether such structures violate current dimensional requirements for setbacks or lot coverage.
(a) For the purposes of this section, "existing structure" means a structure existing on or before July 1, 2025, including detached garages, regardless of whether such structures violate current dimensional requirements for setbacks or lot coverage. Any structure containing an accessory dwelling unit approved and built after July 1, 2025, shall receive protection from future zoning changes in accordance with RSA 674:39, II, provided the structure meets the time periods for reaching active and substantial development in RSA 674:39, I(a) and substantial completion in RSA 674:39, I.
(b) If an existing structure does not comply with current dimensional requirements for setbacks and lot coverage, a municipality may determine eligibility for placement of an accessory dwelling unit within an existing structure by requiring the applicant for the building permit to demonstrate either:
(1) The existing structure qualifies as a preexisting, nonconforming structure exempt from the currently applicable dimensional requirements for setbacks and lot coverage in accordance with RSA 674:19 or any local zoning regulation protecting non-conforming structures; or
(2) The existing structure received a prior zoning approval or determination that it was exempt from the current dimensional requirements for setbacks and lot coverage.
(c) An existing structure converted to an accessory dwelling unit shall not constitute a change of use under RSA 674:19 or any local zoning regulations, which would cause the existing structure to lose its status as a preexisting non-conforming structure.
210:
210:3 Effective Date. This act shall take effect 60 days after its passage.
Approved: July 02, 2026
Effective Date: August 31, 2026