NH · State directory
New Hampshire ADU rules
Official accessory dwelling unit regulations for 12 jurisdictions in New Hampshire, plus statewide law.
Not sure which city yet?
We have read the ordinances for 12 New Hampshire cities and lined them up side by side: detached vs internal, size limits, owner occupancy, and approval process.
Statewide ADU law
New Hampshire has state-level ADU legislation that applies across local jurisdictions. Local rules below may add requirements on top of state law.
- gc.nh.govOfficial sourceVerified September 2026https://gc.nh.gov/rsa/html/LXIV/674/674-72.htm
- gc.nh.govOfficial sourceVerified September 2026https://gc.nh.gov/bill_status/legacy/bs2016/billText.aspx?sy=2026&id=1800&txtFormat=html
- nhhfa.orgOfficial sourceLink outdatedADU Guide Municipalities (PDF)https://www.nhhfa.org/wp-content/uploads/2019/06/ADU_Guide_Municipalities.pdfView archived copy (Wayback Machine)
- nhhfa.orgOfficial sourceVerified July 2026https://www.nhhfa.org/housing-challenges-solutions/accessory-dwelling-units/
- nhmunicipal.orgOfficial sourceVerified August 2026https://www.nhmunicipal.org/town-city-article/make-room-daddy-new-law-accessory-dwelling-units
Cities
Concord3 sources · verified September 2026Derry3 sources · verified September 2026Dover3 sources · verified September 2026Hanover4 sources · verified September 2026Keene4 sources · verified September 2026Laconia4 sources · verified September 2026Lebanon3 sources · verified September 2026Manchester4 sources · verified September 2026Nashua4 sources · verified September 2026Portsmouth4 sources · verified September 2026Rochester3 sources · verified September 2026Salem3 sources · verified September 2026
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