1. A. Routine, continuous disinfection is required of all public water systems.

   1. 1. Where a continuous chloramination (i.e., chlorine with ammonia addition) method is used, water being delivered to the distribution system shall contain a minimum concentration of 0.5 mg/l of chloramine residual (measured as total chlorine).

   2. 2. Where a continuous free chlorination method is used, water being delivered to the distribution system shall contain a minimum concentration of free chlorine residual in accordance with the following table.

      1. a. Table 355.A.2 does not apply to systems using chloramines.
      2. b. pH values shall be measured in accordance with the methods set forth in §1105.D. of this Part.

      Table 355.A.2
      pH Value	Free Chlorine Residual
      up to 7.0	0.5 mg/l
      7.0 to 8.0	0.6 mg/l
      8.0 to 9.0	0.8 mg/l
      over 9.0	1.0 mg/l

2. B. All new groundwater systems installed after July 1, 1996 shall provide at least 30 minutes contact time prior to the first customer. It is recommended that all existing systems provide the 30 minutes contact time prior to the first customer. Additions to or extensions of existing systems are exempt from the 30 minutes contact time.
3. C. Public water systems which use surface water or ground water under the direct influence of surface water shall meet the requirements of applicable Sections of the surface water Treatment rule (LAC 51:XII.Chapter 11) as it pertains to CT and Giardia, Cryptosporidium, and virus removal/ inactivation/disinfection requirements.

Authority Note

AUTHORITY NOTE: Promulgated in accordance with R.S. 40:4(A)(8)(13) and R.S. 40:5(2)(3)(5)(6)(17)(20).

Historical Note

HISTORICAL NOTE: Promulgated by the Department of Health and Hospitals, Office of Public Health, LR 28:1326 (June 2002), amended LR 28:2514 (December 2002), LR 35:1240 (July 2009), LR 38:2376 (September 2012), LR 42:408 (March 2016), amended by the Department of Health, Office of Public Health, LR 44:1252 (July 2018), effective August 1, 2018.