Code of Maryland Regulations
Title 10 - MARYLAND DEPARTMENT OF HEALTH
Part 3
Subtitle 17 - SWIMMING POOLS AND SPAS
Chapter 10.17.01 - Public Swimming Pools and Spas
Section 10.17.01.44 - Disinfection of a Pool and Spa

Universal Citation: MD Code Reg 10.17.01.44

Current through Register Vol. 51, No. 19, September 20, 2024

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.

Disclaimer: These regulations may not be the most recent version. Maryland may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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