N.H. Rev. Stat. Ann. § 477:22-a

Any recorded restriction, order, covenant, or other interest in land held by the state, or any political subdivision of the state, shall be enforceable against any owner of the affected land or structure, including subsequent purchasers, heirs, or assignees, notwithstanding lack of privity of estate or contract, or lack of benefit to particular land, or the benefit being assignable or being assigned.