Code of Massachusetts Regulations
105 CMR - DEPARTMENT OF PUBLIC HEALTH
Title 105 CMR 435.000 - Minimum Standards For Swimming Pools (state Sanitary Code: Chapter V)
Operation and Maintenance
Section 435.29 - Chemical Standards

Current through Register 1531, September 27, 2024

(1) Swimming, wading and special purpose pool water shall be treated in accordance with the following tables:

Type of Disinfection

pH

Alkalinity (ppm) (mg/l)

Residual Chlorine (ppm) (mg/l)

Chlorine

7.2-7.8

50-150

1.0-3.0 Free 0.0-0.2 Combined

Bromine

7.2-7.8

50-150

2.0-6.0

Other equally effective disinfectants registered with the United States Environmental Protection Agency as an approved disinfectant, may be used as a substitute for chlorine or bromine, subject to the approval of the local Board of Health.

(2) Tests for residual disinfectant shall be made four times daily, once during the peak load by the pool operator, or more often if required by the Board of Health.

(3) Hydrogen-Ion Concentration (pH): Tests for hydrogen-ion concentration (pH) shall be made simultaneously with the residual disinfectant test by the pool operator of each swimming pool, and whenever else the Board of Health considers it necessary.

(4) Alkalinity and calcium hardness: Tests for alkalinity and calcium hardness shall be made weekly by the pool operator of each pool and whenever else the Board of Health considers it necessary.

(5) If cyanuric acid is used to stabilize the free available residual chlorine, or if one of the chlorinated is ocyanurate compounds is used as the disinfecting chemical, the concentration of cyanuric acid in the water should be at least 30 mg/l, but shall not exceed 100 mg/l.

(6) When electronic monitoring devices are used in conjunction with chlorine or bromine disinfection at a swimming, wading or special purpose pool, the operator shall check the disinfectant, pH and alkalinity levels manually at least once every 24 hours.

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