Md. Code Regs. 10.17.01.44

Current through Register Vol. 51, No. 25, December 13, 2024

Section 10.17.01.44 - Disinfection of a Pool and Spa

A. An owner or operator of a public pool or spa shall ensure that a disinfectant or combination of disinfectants is added to the water automatically through an approved chemical feeder to maintain continuously a residual level as specified below:

(1) Free chlorine shall be between:

(a) 1.5 ppm and 10.0 ppm in pools for swimming and diving and water recreational attractions;

(b) 3.0 ppm and 10.0 ppm in pools for wading or therapy; and

(c) 4.0 ppm and 10.0 ppm in spas;

(2) The maximum amount of combined chlorine shall be 0.2 ppm for all pools and spas;

(3) Total bromine shall be between:

(a) 3.0 ppm and 8.0 ppm in pools for swimming and diving and water recreational attractions; and

(b) 4.0 ppm and 8.0 ppm in spas and in pools for wading or therapy;

(4) For pools and spas using copper and silver ions as a secondary disinfectant in conjunction with chlorine or bromine as a primary disinfectant:

(a) Copper ions shall be between 0.2 ppm and 1.0 ppm;

(b) Silver ions may not exceed 0.05 ppm;

(c) Free chlorine in combination with copper and silver ions shall be between:

(i) 0.5 ppm and 10 ppm in pools for swimming and diving and water recreational attractions, and

(ii) 1.5 ppm and 10.0 ppm in spas and in a pool for wading or therapy; and

(d) Total bromine in combination with copper and silver ions shall be between:

(i) 1.0 ppm and 8.0 ppm in pools for swimming and diving and water recreational attractions, and

(ii) 3.0 ppm and 8.0 ppm in spas and pools for wading or therapy;

(5) For pools and spas using an ozone generator, the maximum amount of ozone measured 2 inches above the water surface shall be 0.1 ppm;

(6) For pools using PHMB, the minimum level of PHMB shall be 30 ppm; and

(7) For pools and spas using an ultraviolet light/hydrogen peroxide system, the minimum level of hydrogen peroxide shall be 20 ppm.

B. An owner or operator shall ensure that for public pools and spas using cyanuric acid or a similar chlorine stabilizer, the cyanuric acid is maintained between 30 ppm and 100 ppm.

C. An owner or operator of a public pool or spa may not use:

(1) PHMB in a pool or spa that uses jets or sprays;

(2) PHMB in conjunction with any halogen compound or ozone;

(3) Cyanuric acid in conjunction with a bromine compound or in an indoor pool or spa; or

(4) An ultraviolet light/hydrogen peroxide system in conjunction with a diatomaceous earth filter.

Md. Code Regs. 10.17.01.44