N.H. Rev. Stat. Ann. § 131:3

They shall make periodic inspections and analyses of the public water supplies of the state and any special investigations thereof that may be called for; also, when requested or as may be deemed by them necessary or expedient in the interests of the public health, make inspections or analyses of sources furnishing water to institutions, schools, hotels, camps, other places of public resort and individuals, and advise in connection with the same; and they shall enforce the laws pertaining to water supply and to the sanitation of public waters.