1. All pools must be provided with a main drain at the lowest point of the floor of the pool to permit the pool to be completely and easily drained.2. The distance of each main drain from:(a) The nearest main drain must not exceed 20 feet (6.1 meters) on the centers.(b) Any side wall must not exceed 15 feet (4.6 meters).3. The sump of each main drain must be covered with a suitable protective cover or grate securely fastened in such a way that it cannot be removed without the use of tools. The openings in the grate must not exceed 1/2 inch (1.27 centimeters) in diameter. Except as otherwise provided in this subsection, the velocity of water through the grate must not exceed 1.5 feet per second. If only one main drain in the pool is connected to a pump:(a) The drain must be of antivortex design.(b) The velocity of water through the grate must not exceed 6 feet per second.4. The recirculation system must be designed to guard against outlet entrapment. Any of the following means may be employed:(a) The system must include no fewer than two main drains, separated by not less than 4 feet (1.22 meters), and connected to pipes of equal diameter. The system must not permit any cutoff of either drain from the suction line.(b) The system must include one or more antivortex outlet drains. Any drain installed at a depth of 4 1/2 feet (1.37 meters) or less must not present a tripping hazard to the bather.(c) Any other system, approved by the health authority, that guards against outlet entrapment.5. Valves or pumps used for draining pools must be sized to prevent the surcharging of the receiving drain. Multiport valves must:(a) Comply with all applicable requirements of Standard 50 of the National Sanitation Foundation. A copy of this standard may be obtained from the National Sanitation Foundation, P.O. Box 1468, Ann Arbor, Michigan 48106, at a cost of $8.(b) In the absence of an applicable standard, be approved by the health authority.6. The main drains must be capable of taking at least 50 percent of the circulated flow.7. As used in this section: (a) "Antivortex drain" means a drain having a raised cover designed to prevent or minimize any suctioning effect on a person that comes into contact with the drain.(b) "Multiport valve" means a separate switching valve that has a separate position for each of the various filter operations and that combines in one unit the functions of two or more direct-flow valves.Nev. Admin. Code § 444.158
Bd. of Health, Public Bathing Places Reg. Art. 26 §§ 26.7-26.7.4, eff. 5-21-74-NAC A 9-17-82; 11-1-88