N.H. Rev. Stat. § 23:1-a

I. In addition to the powers conferred upon counties as set forth in RSA 23:1, each such county is hereby empowered to exercise full jurisdiction over the planning, construction, and operation of water supply, sewage collection, and treatment facilities and such other utilities as are essential to the proper maintenance of county buildings and the protection of the public health of the inhabitants of such institutions. II. Each county is further empowered to exercise jurisdiction over the operation of water supply and sewage collection in such areas adjacent to county buildings as are determined by the department of environmental services to be capable of being served cost effectively within the meaning of federal and state statutes, and which are not served or intended to be served by a municipal system. III. In addition to the powers conferred by paragraphs I and II, the county of Carroll is further empowered to exercise jurisdiction over, to operate, and maintain a public water system within the borders of the town of Ossipee, notwithstanding that such areas are not adjacent to county buildings. IV. Any county government, located within the service territory of a municipal electric utility established prior to July 1, 1997 that does not voluntarily unbundle its rates and allow access to competitive retail electric supply markets as provided in RSA 38:34, shall have access to such markets and may negotiate competitive, reasonable, unbundled rates.