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Title: Section 6-1.11 - Treatment

Effective Date


6-1.11 Treatment. All swimming pools shall be equipped with a recirculation system which includes filtration and disinfection facilities to provide water quality consistent with the bacteriological, chemical and physical standards required in section 6-1.19 of this Subpart.

(a) Turnover rate. The entire volume of pool water must be recirculated and treated in six hours. Pools constructed prior to March 31, 1973 may have an eight-hour turnover rate. Pools with approved design rate of less than six hours shall be operated at the design rate.

(b) Filtration. (1) Sand filters.

(i) Gravity and pressure-type sand filters shall be operated at a filter rate not to exceed three gallons per minute per square foot (gpm/sf). High-rate sand filters (pressure or vacuum) can be operated at a filter rate up to 15 gpm/sf.

(ii) Filter air release valves shall be opened daily, or more frequently if necessary to remove air which collects in the filters.

(iii) Sand filters shall be backwashed at a flow rate of 12 to 15 gpm/sf or at the design rate recommended by the manufacturer.

(2) Diatomaceous earth filters. (i) Diatomaceous earth filters shall be properly maintained and operated according to the manufacturer's instructions and at a filter rate not to exceed two gpm/sf with body feed or 1.5 gpm/sf without body feed.

(ii) Diatomaceous earth filter backwash water must discharge to the sewer system through a separation tank. The separation tank sludge shall be disposed of or treated as a solid waste material in accordance with local and State laws, rules and regulations.

(3) Cartridge filters. (i) Cartridge filters shall be operated at a filter rate not to exceed the design rate or a maximum of 0.375 gpm/sf.

(ii) Cleaning of cartridge filters must be in accordance with the manufacturer's recommendations. One complete spare set of cartridges shall be available at all times to facilitate cleaning.

(4) Flow measurement. All flow meters shall be maintained in accordance with provisions in section 6-1.29, item 9.8, of this Subpart.

(c) Disinfection. (1) Disinfection with chlorine. When chlorine gas, calcium hypochlorite or sodium hypochlorite is used to disinfect a swimming pool and the pool water pH is less than or equal to 7.8, the dose of chlorine or chlorine compound shall be sufficient to maintain a concentration of at least 0.6 mg/l free chlorine throughout the swimming pool. When the pH is between 7.8 and 8.2, a concentration of at least 1.5 mg/l free chlorine residual shall be maintained. A free chlorine residual of 5.0 mg/l or a pH of 8.2 shall not be exceeded in any swimming pool during use. All chlorine solutions shall be added to the pool water by chemical feed equipment conforming with standards contained in Section 6-1.29, Item 11.1 of this Subpart.

(i) Handling of chlorine gas. When chlorine gas is used as a disinfectant, the chlorinators and any cylinders containing chlorine gas used therewith shall be housed in an enclosure separated from other equipment rooms, including the swimming pool, corridors, dressing rooms and other space used by the bathers, by a tight partition wall or by a tight partition wall with a door so installed as to prevent gas leakage and equipped with an inspection window. Chlorine cylinders shall be secured from falling and cylinders in use shall be secured on a suitable platform scale. A separate vent opening to the exterior shall be provided. An electric motor-driven fan shall take suction from near the floor level of the enclosure and discharge at a suitable point to the exterior above the ground level. The fan switch shall be able to be operated from outside of the enclosure. All pools using chlorine gas shall be equipped with a self-contained breathing apparatus which is kept in a closed cabinet, outside of the room in which the chlorinator is maintained. The breathing apparatus shall be maintained in working order and checked monthly. Additional precautions shall be taken in the handling and storage of chlorine gas at pools as required by the permit-issuing official to safeguard public health. Any person who operates such chlorinating equipment shall be familiar with the use of self-contained breathing apparatus.

(ii) Handling of calcium hypochlorite. When calcium hypochlorite is used as a disinfectant, extreme caution must be taken in the handling and mixing of the chemical to avoid possible fire and explosion hazards. A dry, aboveground, locked storage area shall be provided. Clean inert materials shall be used, and mixing must be by pouring the chemical into water and never by pouring water into the chemical.

(2) Disinfection with bromine. When bromine is used as the disinfectant, the following shall be followed:

(i) Bromine shall be fed on a continuous basis.

(ii) The pool pH shall be maintained between 7.2 and 7.8.

(iii) A concentration of at least 1.5 mg/l bromine residual shall be maintained throughout the pool water at all times. A maximum of six mg/l bromine residual shall be permitted in any swimming pool during use.

(iv) Solid-stick or tablet-type bromine (brom-chlor-dimethyl-hydantoin) shall be used with feed equipment conforming to the standards contained in section 6-1.29, item 11.4, of this Subpart.

(3) Other disinfectants. Disinfectants other than those listed above may be used only if the State Commissioner of Health determines they are safe and effective when used in accordance with the manufacturer's directions.

(4) Use of cyanuric acid-based chlorine (or any other chlorine stabilizer) is prohibited. Pools found using or containing any cyanuric compound shall be closed, drained and refilled prior to continued use.

(5) Test kits/testing. DPD test kits with reagents no more than one year old capable of measuring pH and chlorine or bromine residuals, shall be available at each pool. Tests shall be conducted and recorded for pH and free and total chlorine or bromine residual at the beginning, during, and at the end of each swimming period. Where required, r eagents for alkalinity and hardness tests shall be available. Where ozone generating equipment is installed, ozone testing shall be conducted in accordance with section 6-1.29, Item 11.5.1 of this Subpart.

(d) Chemicals. When the permit-issuing official determines that pH is not consistently maintained within the required limits, positive feed equipment shall be used to maintain the pH at levels required in this section. The methods for addition of pool water treatment chemicals must be specified and approved in the safety plan. The method of chemical addition must protect the bather from contact with concentrated chemicals. The method must provide adequate distribution of the chemical throughout the pool and distribution must be verified by pool water testing prior to bather exposure. Only chemicals approved for water supply use by the U.S. Environmental Protection Agency, as food additives by the U.S. Food and Drug Administration, or by the State Commissioner of Health, shall be used in swimming pools. Where equipment for chemical addition is required, it shall be installed and operated in accordance with section 6-1.29, item 11.0 of this Subpart. All chemical containers, including those used with chemical feeders, must be clearly labeled regarding their contents.


VOLUME A (Title 10)