In addition to the definitions in 50-53-102 , MCA, the following definitions apply to this subchapter:

(1) "Backwash" means the process of thoroughly cleansing the filter media and/or elements by reverse water flow.

(2) "Bather" means any person using a swimming pool, spa or adjoining deck area for the purpose of water sports, therapy, swimming, sunbathing or related activities.

(3) "Decks" means those areas immediately surrounding and adjoining the pool which are specifically constructed or installed for use by bathers.

(4) "Deep areas" means the portions of the pool having water depths of 5 feet or more.

(5) "Filter" means a device that separates solid particles from water by recirculating them through a porous substance.

(6) "Floor" means those portions of the interior pool surface having a slope of no more than 45 E from horizontal.

(7) "Flow-through hot springs pool" means a hot springs pool in which the water is continually flowing and in which the water volume exchange is sufficient to produce a turnover of the entire volume of pool water to waste every 8 hours.

(8) "Hot springs pool" means an indoor or outdoor structure or basin containing an artificial body of naturally hot water, which is intended for swimming, soaking or recreational bathing. The term, as used in these rules, includes but is not limited to hot springs spas, hot springs swimming pools and hot springs wading pools.

(9) "Lap pool" means any indoor or outdoor pool with a minimum depth exceeding 3 feet 6 inches and a maximum depth not exceeding 5 feet with a minimum length of 40 feet.

(10) "Oxidation reduction potential (ORP) " means measurement of the oxidizing properties of any sanitizer being used in a pool or spa and is measured in millivolts (mV) by an ORP meter.

(11) "Person" means a person, firm, partnership, corporation, organization, health or fitness club, the state or any political subdivision of the state of Montana.

(12) "Regulatory authority" means the department of public health and human services or local boards of health and their authorized representatives.

(13) "Saturation index" means a mathematical calculation, based on the interrelation of temperature, calcium hardness, total alkalinity and pH, that predicts if the pool water is corrosive, scale-forming or neutral.

(14) "Shallow area" means any portion of the pool where the water depth ranges from three feet to five feet.

(15) "Spa" means a unit designed for recreational bathing or therapeutic use which is not drained, cleaned or refilled for individual use. It may include, but not be limited to, hydrojet circulation, hot water, cold water, air induction bubbles, or any combination thereof. Industry terminology for a spa includes, but is not limited to, therapeutic pool, hydrotherapy pool, whirlpool, hot tub, or jacuzzi. A spa is included as either a public swimming pool or a privately owned public swimming pool, as defined in (17) (a) and (b) and includes a hot springs spa, for the purposes of this subchapter.

(16) "Superchlorination" means the rapid addition of a high dose of chlorine to swimming pool or spa waters for the purpose of eliminating combined chlorine levels.

(17) "Swimming pool" or "pool" means any indoor or outdoor structure, basin, chamber, or tank containing an artificial body of water intended for swimming, diving or recreational bathing having a water depth of 2 feet or more in any portion. For purposes of this subchapter, a "swimming pool" or "pool" is either:

(a) "Privately owned public swimming pool or spa" meaning any swimming pool or spa operated in conjunction with lodging facilities, (such as motels, hotels, campgrounds, apartments, and condominiums that are rented or leased) , health or athletic clubs, or any other non-governmentally owned swimming or bathing facility; or

(b) "Public swimming pool or spa" meaning any swimming pool or spa operated by a person as owner, licensee, lessee, or concessionaire, whether or not a fee is charged. As stated in 50-53-101 , MCA, the term "public swimming pool or spa" does not include swimming pools or spas located on private property used for swimming, bathing, or other recreational activities only by the homeowner, members of the homeowner's family, or their invited guests; or medicinal hot water baths for individual use. Any person who is charged money or other consideration to use the pool is not an invited guest for the purposes of this definition.

(18) "Turnover" means the period of time, usually expressed in hours, required to circulate a volume of water equal to the spa capacity.

(19) "Wading pool" means a pool in which the water depth is less than 2 feet.

(20) "Walls" means the interior pool wall surfaces with slope of no more than 45 E from vertical.

(21) "Waterline" means:

(a) the middle point of the operating range of the skimmer system if the pool is so equipped; or

(b) the height of the overflow rim.