"Spa" means a water-containing structure, sometimes called a hot tub or jacuzzi, that is designed for recreational or therapeutic use and for physiological and psychological relaxation but not for swimming or diving. These facilities are not drained and refilled after each use, instead the water is circulated, filtered, and sanitized. Spas include hydrojet circulation, hot water, cold water, mineral baths, and air induction systems. The term includes structures that are in a fixed location and structures that are intended to be moved from place to place on a rental or other commercial basis.
N.H. Admin. Code § Env-Wq 1102.55