N.H. Rev. Stat. Ann. § 479-A:2

This chapter shall be applicable only to property which the sole owner or all the owners thereof or, in the case where the property is leased of another for a period of not less than 30 years, the sole lessee or all the lessees thereof submit to the provisions hereof by duly executing and recording a declaration as provided in RSA 479-A:10 and 479-A:14.