D.C. Mun. Regs. tit. 25, r. 25-C404

Current through Register Vol. 71, No. 49, December 6, 2024
Rule 25-C404 - WATER QUALITY - STANDARDS, CHEMICAL QUALITY*
404.1

The Department may collect water samples and examine them as necessary to determine compliance with these regulations.

404.2

Chemicals used in controlling the quality of the pool water shall be tested and approved using the National Sanitation Foundation (NSF-ANSI) Standard 60, 2005, which is incorporated by reference into these rules and shall be compatible with other accepted chemicals used in pools. The following parameters shall be adhered to when treating water for swimming pools, spa pools or saunas:

(a) Maintain water pH between 7.2 to 7.8; however:
(1) Water pH shall not be below 6.5; or
(2) Water pH shall not be above 8.0;
(b) Use the following disinfectants -
(1) Free chlorine residual shall be 1 milligram per liter (mg/L) to 10 mg/L, inclusive, in conventional swimming pools.
(2) Free chlorine residual shall be 2 mg/L to 10 mg/L, inclusive, in all other type pools such as spa-type pools, except spa-type pools which shall be at the minimum of 3 mg/L.
(3) Bromine residual shall be 1.5 mg/L to 8 mg/L, inclusive, in conventional swimming pools and 4 mg/L to 8 mg/L, inclusive, in all spa-type pools.
(4) Except that, the following maximum disinfectant levels shall apply to indoor conventional swimming pools: 5 mg/L free chlorine or 6 mg/L bromine;
(c) The level of combined Chlorine (Chloramines) use shall not exceed 0.4 ppm (mg/L) - Water with combined chlorine (chloramines) levels in excess of 0.4 ppm (mg/L) shall be reduced by the following actions:
(1) Super-chlorination; or
(2) Water exchange;
(d) When oxidation reduction potential controllers are used - Water potential shall be kept between six hundred to nine hundred millivolts (600 - 900 mv). Use of these units does not negate the manual daily testing requirement of Section 412;
(e) Use of cyanuric acid - shall remain between 30 and 50 mg/L and shall not exceed 100 ppm in swimming pools and in spa pools; and
(f) Use of quaternary ammonium - 5 mg/L maximum.
404.3

Irrigation water that wets the deck area of a pool and the water in the pool shall be potable water. Non-potable irrigation water shall not be applied within ten feet (10 ft.) of the wet deck area.

404.4

Manual addition of chemicals will be allowed under special conditions and requires the pool to be closed prior to addition and for at least one (1) hour after addition, or a longer period as necessary, for sufficient and safe distribution of the chemical. After treatment for breakpoint chlorination and algae prevention, use of the pool can be resumed when the free chlorine levels drop to 10 mg/L, or in compliance with the Safety Data Sheets.

D.C. Mun. Regs. tit. 25, r. 25-C404

Final Rulemaking published at 64 DCR 5359 (6/9/2017)