Accessory Structures in New Hampshire (2026)
8 rules on the books across New Hampshire, 3 cities and counties. Select a rule to read the full details.
Severity: Few Restrictions · Light Restrictions · Some Restrictions · Significant Restrictions · Heavy Restrictions
ADU Rules
Rules for building accessory dwelling units (granny flats, in-law suites) including size limits, parking requirements, and owner-occupancy rules.
New Hampshire: statewide
StatewideFew RestrictionsNew Hampshire RSA 674:71 to 674:73 requires every municipality that allows single-family homes to permit at least one…
Read full rule →Hudson
Significant RestrictionsIn the Town of Hudson, New Hampshire, an accessory dwelling unit has to be built inside or attached to the…
Read full rule →Manchester
Some RestrictionsManchester requires a detached accessory dwelling unit to tie into the sewer service that already runs to the main…
Read full rule →Nashua
Some RestrictionsNashua accessory dwelling units are capped at 980 square feet (1,200 if built within an existing footprint), require…
Read full rule →ADU Owner Occupancy
Whether the property owner must live on-site to operate an ADU, deed-restriction requirements, and recent state-law changes lifting owner-occupancy rules.
Hudson
Some RestrictionsIn the Town of Hudson, New Hampshire, an accessory dwelling unit is allowed only inside a single-family home, and the…
Read full rule →Nashua
Some RestrictionsNashua's accessory dwelling unit ordinance requires the property owner to live in either the primary house or the ADU…
Read full rule →Shed & Carport Rules
When a storage shed or carport needs a permit, the square-footage exemption thresholds, and the setback and height limits that apply either way.
Hudson
Some RestrictionsIn the Town of Hudson, New Hampshire, a detached shed needs a building permit and a fee tied to its size: $40 for up to…
Read full rule →Nashua
Some RestrictionsNashua charges a flat $30 minimum permit fee for residential sheds under 200 square feet, billed as miscellaneous…
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