N.H. Rev. Stat. § 48-A:7
An ordinance, code or bylaw adopted by a municipality pursuant hereto shall provide that the public agency may determine that a dwelling is unfit for human habitation if he finds that conditions exist in such dwelling which are unusually, abnormally, or unreasonably dangerous or injurious to the health or safety of the occupants of such dwelling, the occupants of neighboring dwellings or other residents of such municipality. Such conditions may include the following: Defects which increase beyond normal the hazards of fire, accident, or other calamities; lack of reasonable adequate ventilation, light, or sanitary facilities; dilapidation; disrepair, dangerous structural defects; uncleanliness; over-crowding; inadequate ingress and egress; inadequate drainage; or any violation of other health, fire or safety regulations.
RSA 48-A:7
1959, 293:1, eff. Nov. 16, 1959.