Louisiana Administrative Code
Title 51 - PUBLIC HEALTH-SANITARY CODE
Part XII - Water Supplies
Chapter 3 - Water Quality Standards
Section XII-367 - Disinfectant Residual Monitoring and Record Keeping [formerly paragraph 12:021-7]

Universal Citation: LA Admin Code XII-367

Current through Register Vol. 50, No. 12, December 20, 2024

A. Disinfectant Residual Monitoring in Treatment Plant. A public water system shall measure the residual disinfectant concentration in water being delivered to the distribution system at least once per day.

B. Disinfectant Residual Monitoring in Distribution System. A public water system shall measure the residual disinfectant concentration within the distribution system:

1. by sampling at the same points in the distribution system and at the same times that samples for total coliforms are required to be collected by the public water system under this Part;

2. by sampling at an additional number of sites calculated by multiplying 0.25 times the number of total coliform samples the public water system is required under this Part to take on a monthly or quarterly basis, rounding any mixed (fractional) number product up to the next whole number. These additional residual monitoring samples shall be taken from sites in low flow areas and extremities in the distribution system at regular time intervals throughout the applicable monthly or quarterly sampling period; and

3. by sampling at the site that represents the maximum residence time (MRT) in the distribution system at least once per day.

C. A public water system shall increase sampling to not less than daily at any site in the distribution system that has a measured disinfectant residual concentration of less than 0.5 mg/l free chlorine or 0.5 mg/l chloramine residual (measured as total chlorine) until such disinfectant residual concentration is achieved at such site.

D. The records of the measurement and sampling required under Subsections A and B of this Section shall be maintained on forms approved by the state health officer and shall be retained as prescribed in the national primary drinking water regulations, and shall be made available for review upon request by the state health officer.

E. Each public water system shall submit a monitoring plan to the state health officer for review and approval. The monitoring plan shall be submitted in a format approved by the state health officer and shall include all the total coliform and disinfectant residual monitoring sites required under this Section and §903. A of this Part. All monitoring sites shall be identified along with a 911 street address, a latitude/longitude coordinate, and a brief description of the site location. A public water system in existence as of November 6, 2013 shall submit such a monitoring plan no later than January 1, 2014 and shall update the monitoring plan as requested by the state health officer and/or as monitoring sites change.

F. Chlorine residuals shall be measured in accordance with the analytical methods set forth in §1105. C of this Part.

G. Where a continuous chloramination (i.e., chlorine with ammonia addition) method is used or where water that is provided to customers contains chloramines, a nitrification control plan shall be developed and submitted to the state health officer. A public water system in existence as of November 6, 2013 shall submit and comply with such a nitrification control plan no later than January 1, 2017. The plan shall conform to the guidelines contained in industry standards such as the American Water Works Associations M56 Manual on Nitrification and contain at least the following information:

1. at a minimum, the following parameters shall be monitored and recorded in accordance with the following:
a. free ammonia at least once per week in water being delivered to the distribution system (i.e., point of entry) unless an alternate measurement or method is approved by the state health officer;

b. nitrite at least once per quarter and in response to an action level trigger within the distribution system at sites prone to nitrification such as storage tanks and low flow areas;

2. a response plan with expected water quality ranges and action levels to control nitrification and ensure compliance with §357 of this Part.

H. Public water systems utilizing chloramination shall review and update the nitrification control plan required under Subsection G of this Section as requested by the state health officer.

1. In addition, the nitrification control plan and monitoring results shall be retained on-site for a minimum of five years and shall be made available to the state health officer upon request and/or when the public water system fails to comply with §357 of this Part.

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

Disclaimer: These regulations may not be the most recent version. Louisiana 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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