(1) Swimming pool filters shall be designed, constructed and operated to the satisfaction of the medical officer of health.
(2) Despite subregulation (1) filtration surfaces shall be so constructed that they may be easily restored to the designed capacity. Facilities shall be provided so that the restoration of such surfaces can be accomplished without contamination of the pool and so that—
(a) filtration surfaces are esaily available for inspection; and
(b) structural or functional failures will not occur permitting passage of unfiltered water.
(3) In the case of rapid sand filters, the filtration rate shall not exceed 3 gallons per square foot per minute, and the backwash shall be at a rate of not less than 12 gallons per square foot per minute.
(4) Filter piping shall be valved so that filters can be washed individually allowing each filter to be isolated for repairs while the other units are in service.
(5) Diatomaceous earth filters shall be designed so that the filtration rate shall not exceed 2 gallons per square foot per minute, with maximum rates of 2½ gallons per square foot per minute for filters designed for continuous feeding of filter aid.
(6) Provisions shall be made for all filters to be cleaned by means of back washing or in a manner which is satisfactory to the medical officer of health.
(7) For pressure type units the pump shall be capable of delivering full required capacity at a head loss of 60 feet and 60 percent or more of such capacity at 70 feet head loss.
(8) There shall be at least one skimmer for each 500 square feet of pool surface area or part thereof, except that for pools which do not exceed 600 square feet in surface area, one skimmer only may be provided.