N.H. Rev. Stat. § 270-E:19
Every common carrier by water shall establish and charge just and reasonable rates for transportation of passengers or property on the public waters of the state. Such rates and tariffs, together with a schedule of the service offered, shall be published, filed with the department and kept open to public inspection, and no common carrier shall demand or collect or receive a greater or less or different compensation for transportation than the rates specified in the tariff in effect at any time. Any person, organization, or body politic may make complaint in writing to the department that any rate, fare, or charge in effect, or proposed to be put in effect, is or will be unjust or unreasonable. Whenever, after hearing, upon complaint or in an investigation on its own initiative, the department shall be of the opinion that any rate, fare or charge in effect or proposed to be in effect is unjust or unreasonable, the department shall determine and prescribe the lawful rate, fare, or charge thereafter to be observed.
RSA 270-E:19
1990, 229:1, eff. Jan. 1, 1991.