From the 2006 IRC.
SECTION P2720
WHIRLPOOL BATHTUBS
SECTION E4109
- HYDROMASSAGE BATHTUBS
- - HYDROMASSAGE BATHTUB. A permanently installed bathtub equipped with a recirculating piping system, pump, and associated equipment. It is designed so it can accept, circulate and discharge water upon each use.
From the NEC. (any edition)
- ARTICLE 680 Swimming Pools, Fountains, and Similar Installations
- - 680.2 Definitions.
- - - Hydromassage Bathtub. A permanently installed bathtub equipped with a recirculating piping system, pump, and associated equipment. It is designed so it can accept, circulate, and discharge water upon each use.
- - VII. Hydromassage Bathtubs
They are, then, by most codes and by definition, "hydromassage bathtubs".