N.H. Code Admin. R. Env-Ws 382.08

Current through Register No. 25, June 20, 2024

Section Env-Ws 382.08 - Routine Monitoring Requirements for TTHM and HAA5

(a) The owner of a SW/GWUDISW system serving 10,000 or more persons shall:

(1) Maintain a minimum monitoring frequency by collecting at least 4 water samples per quarter per treatment plant;

(2) Collect at least 25% of all samples collected each quarter at locations representing maximum residence time in the distribution system; and

(3) Collect the remaining 75% of all samples at locations representative of at least average residence time in the entire distribution system which shall be based on:

a. Number of persons served;

b. Sources of water; and

c. Treatment methods.

(b) The owner of a SW/GWUDISW system serving 500 to 9,999 persons shall:

(1) Maintain a minimum monitoring frequency by collecting one water sample per quarter per treatment plant; and

(2) Collect samples at locations representing maximum residence time in the distribution system.

(c) The owner of a SW/GWUDISW system serving fewer than 500 persons shall:

(1) Maintain a minimum monitoring frequency by collecting one sample per year per treatment plant during the month of warmest water temperature based on historic water temperature records;

(2) Collect samples at locations representing maximum residence time in the distribution system; and

(3) If the sample, or average of annual samples, if more than one sample is collected, exceeds the MCL, monitoring shall be increased to one sample per treatment plant per quarter, collected at a point representing maximum residence time in the distribution system until the system meets the reduced monitoring criteria specified in Env-Ws 382.09.

(d) The owner of a system using only groundwater not under direct influence of surface water treated with a chemical disinfectant and serving at least 10,000 persons shall:

(1) Maintain a minimum monitoring frequency by collecting one water sample per quarter per treatment plant; and

(2) Collect samples at locations which represent maximum residence time in the distribution system.

(e) The owner of a system using only ground water not under the direct influence of surface water treated with a chemical disinfectant and serving fewer than 10,000 persons shall:

(1) Maintain a minimum monitoring frequency by collecting one sample per year per treatment plant during the month of warmest water temperature;

(2) Collect samples at locations that represent maximum residence time in the distribution system; and

(3) If the sample, or average of annual samples, if more than one sample is collected, exceeds the MCL, increase monitoring to one sample per treatment plant per quarter, collected at a point representing the maximum residence time in the distribution system, until the system meets the criteria for reduced monitoring specified in Env-Ws 382.09.

(f) If a system owner elects to collect samples more frequently than the minimum required pursuant to this section, at least 25% of all samples collected each quarter, including those taken in excess of the required minimum, shall be collected at locations that represent the maximum residence time of the water in the distribution system.

(g) The remaining samples in (f) above, shall be collected at locations representative of at least average residence time in the distribution system.

N.H. Code Admin. R. Env-Ws 382.08

(See third Revision Note at chapter heading Env-Ws 300); #7735, eff 8-2-02