(1) The circulation system shall use at least 70 percent return water from the skimmers or gutters and the remainder from the main drain. The main drain percentage may be increased during nonoperational hours to assist in debris removal.

(2) The recirculation system must be operated 24 hours a day. If the system is shut down for periodic maintenance and repair, no person, including any employee of the facility, may be allowed to use the swimming pool, spa, or other water feature.

(3) No more than two spa units may use one recirculation system and no spa may utilize the recirculation or disinfection system of a pool or other water feature. Wading pools and spas constructed after March 1, 2010 must have their own recirculation system separate from any other pool or spa.

(4) A surface skimming system such as the overflow gutters or skimmers described in ARM 37.115.1008 and 37.115.1009 shall be provided for each pool, spa, or other water feature.

(5) The water velocity in the recirculation system piping shall not exceed:

(a) ten feet per second for discharge piping, except for copper pipe where the velocity shall not exceed six feet per second;

(b) six feet per second for suction piping; or

(c) one and one half feet per second through suction grates.

(6) Recirculation system inlets and outlets shall be installed in a location that will produce uniform circulation of water and which will maintain even distribution of sanitizer residual throughout the pool, spa, or other water feature. Inlets and outlets shall be designed and installed so that they do not constitute a hazard to the user.