ADU rules in Hanover

Hanover now treats detached and attached ADUs identically. Section 702.2 allows one accessory dwelling unit as a permitted use in the D, RO, I, GR, SR and RR districts once the Zoning Administrator issues a zoning permit confirming compliance. The May 12, 2026 Town Meeting deleted former Section 702.2 G, which had capped a detached ADU at the lesser of 25 feet or the height of the principal dwelling and allowed conversions only of accessory structures standing on May 9, 2017; the Planning Board described 2026 warrant Article #3 as 'removing the distinctions between attached and detached ADUs' to comply with state law. New Section 702.2 F lets any accessory structure legally existing as of July 1, 2025, including a detached garage, be converted to an ADU even if it violates current setback or lot coverage requirements. RSA 674:73, as rewritten by 2025 NH Laws chapter 197 effective July 1, 2025, independently requires every municipality to permit one detached ADU.

The same permission and the same permit path cover a basement unit, an internal conversion or an addition. Section 702.2 makes one ADU a permitted use in the D, RO, I, GR, SR and RR districts without distinguishing unit types, and the 2026 amendment also deleted the old attached-ADU design rules (only one street-facing entrance, no street-facing fire escapes or exterior stairs, exterior finishes matching the principal dwelling), so an attached unit faces no ADU-specific design standards outside the West End Neighborhood Overlay. A lot may contain only one ADU and the principal structure must be a one-family dwelling. RSA 674:72, I requires one ADU, attached or detached, as a matter of right in every district that permits single-family dwellings.

Section 702.2 C caps an ADU at 1,000 square feet of gross floor area and sets a 350 square foot floor, with the 1,000 measured as gross floor area less the area of any space with a ceiling height under five feet, and allows no more than two bedrooms. Hanover's 1,000 square foot ceiling sits above the 950 square foot state default in RSA 674:72, VII, which a municipality may raise, and well above the 750 square feet the state forbids municipalities to go below. Section 702.2 B separately requires the unit to be 'subsidiary to the principal dwelling unit on the lot.' Watch one wrinkle: the same May 2026 Town Meeting (warrant Article #4) removed the definitions of 'gross floor area' and 'gross floor area ratio' from Section 302, so the term Section 702.2 C measures by is no longer defined in the ordinance.

Section 702.2 A permits an ADU on a lot only if 'one of the units on the lot is owner-occupied' and the principal structure is a one-family dwelling. Section 302 defines an owner-occupied dwelling as one that is 'the actual and principal residence of its owner, who is continuously present in the dwelling unit,' so this is an ongoing condition of the permitted use rather than a one-time test at application, and the owner may occupy either unit. The requirement survived the 2025 state ADU expansion: RSA 674:72, VI still lets a municipality require owner occupancy of one of the units, bars it from dictating which unit, and allows reasonable enforcement regulations. Hanover's older ADU checklist handout also required a recorded Notice of Restriction covenanting owner occupancy and no condominium conversion; the 2026 ordinance text contains no covenant requirement, so confirm current practice with the Planning, Zoning & Codes office.

No additional off-street parking is required for an ADU. The May 12, 2026 Town Meeting deleted former Section 702.2 E ('Parking adequate for the accessory dwelling unit must be provided on site pursuant to Article X'), and the Planning Board's warrant description for Article #3 says the change brings Hanover into compliance with state law by 'deleting parking requirements.' Article X as it now reads sets no numeric residential minimum at all: Section 1001.6 leaves space counts to the Planning Board only for commercial and multi-family uses through site plan review, and Section 1001.7 lets the Zoning Administrator waive spaces that an earlier version of Article X had required. RSA 674:72, IV would have permitted Hanover to require up to one extra space per ADU, on-site or at a legally dedicated off-site location at the owner's choice; Hanover did not take it. Sections 519.3 and 519.4 G still say parking for rented rooms and short-term rentals must be provided 'in accordance with Article X,' which now supplies no number.

Administrative, with no discretionary hearing. Section 702.2 makes an ADU 'a permitted use in the D, RO, I, GR, SR and RR districts after a zoning permit is issued by the Zoning Administrator confirming compliance with all of the following criteria,' so no special exception and no variance is involved. Under Section 205.3 the Zoning Administrator notifies abutters when a complete residential application is received, determines compliance, and must issue the permit within 15 calendar days of the completeness determination. The permit is then posted publicly and does not take effect for 15 calendar days, during which an appeal of the Administrator's determination may be filed with the Zoning Board of Adjustment under RSA 676:5; the 2026 Town Meeting extended the general appeal window in Section 206.5 D to 30 days. A building permit and Certificate of Occupancy run through the town's online permitting system.

An ADU may be rented long term, but every rented unit in Hanover must be registered and hold a Certificate of Compliance under Rental Housing Ordinance #42, approved at Town Meeting on May 9, 2023: it is 'unlawful for anyone to rent, or offer for rent, any Unit without a Certificate of Compliance,' inspections run on a three-year cycle, and the fees are $50 per unit to apply plus $250 per unit to inspect. Short-term rental is effectively closed to ADUs: Section 519.4 B states that 'Un-hosted short-term rental is not permitted in an accessory dwelling unit,' and Section 519.4 A authorizes hosted short-term rental only of 'rooms without separate cooking facilities in a one-family dwelling unit,' which an ADU is not; the town's Rental Housing page says plainly that 'ADUs may not be used for short-term rentals.' Occupancy of any rental is bounded by the Section 302 definition of 'family,' which tops out at three unrelated adults, and by the two-bedroom cap in Section 702.2 C. RSA 674:72, I prohibits selling an ADU off by subsequent condominium conveyance unless the municipality allows it, and Hanover's ordinance does not.