Pools and spas shall be continuously disinfected by an approved means, which will maintain an adequate and readily measurable residual of disinfectant in the water.
a. Whenever chlorine, or a chlorine compound, is employed for pool disinfection the amount of free chlorine residual in the water shall not be less than 1.0 ppm or more than 5.0 ppm for public and semipublic swimming pools, and shall not be less than 3.0 ppm or more than 5.0 ppm for a hydrotherapy pool, at a pH of 7.2 to 7.8.
b. Bromine disinfection equipment for a public or semipublic swimming pool shall be designed to maintain a bromine residual of 2.0 ppm to 4.0 ppm. Bromine disinfection equipment for a public or semipublic spa shall be designed to maintain a bromine residual of 3.0 ppm to 5.0 ppm.
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REGULATION 6. Tests
All pools shall be equipped with approved test equipment to determine pH, disinfectant residual, total alkalinity and temperature. The chemical disinfection level, pH, total alkalinity, and temperature of the water shall be tested at least once daily and an operating log that includes the results of these tests shall be maintained for 12 months and made available to the Department, any other regulatory authorities, or a member of the public upon request.
http://www.maricopa.gov/EnvSvc/AboutUs/pdf/C6S2.pdf