Figure: 30 TAC §290.113(c)(4)

STAGE 1 REDUCED MONITORING FREQUENCY
AND LOCATIONS FOR TTHM AND HAA5

IF YOU ARE A... YOU MAY REDUCE MONITORING IF YOU HAVE MONITORED AT LEAST ONE YEAR AND YOUR... TO THIS LEVEL
Surface water or groundwater under the direct influence of surface water system serving at least 10,000 persons which has a source water annual average TOC level, before any treatment, less than or equal to 4.0 mg/L1 TTHM annual average less than or equal to 0.040 mg/L and HAA5 annual average less than or equal to 0.030mg/L one sample per treatment plant per quarter at distribution system location reflecting maximum residence time
Surface water or groundwater under the direct influence of surface water system serving from 500 to 9,999 people which has a source water annual average TOC level, before any treatment, less than or equal to 4.0 mg/L1 TTHM annual average less than or equal to 0.040 mg/L and HAA5 annual average less than or equal to 0.030mg/L one sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature.
Surface water or groundwater under the direct influence of surface water system serving fewer than 500 people   Any surface water or groundwater under the direct influence of surface water system serving fewer than 500 persons may not reduce its monitoring to less than one sample per treatment plant per year.
System using only groundwater not under direct influence of surface water using chemical disinfectant and serving at least 10,000 persons TTHM annual average less than or equal to 0.040 mg/L and HAA5 annual average less than or equal to 0.030mg/L one sample per treatment plant per year at distribution system location reflecting maximum residence time during month of warmest water temperature
System using only groundwater not under direct influence of surface water using chemical disinfectant and serving fewer than 10,000 persons TTHM annual average less than or equal to 0.040 mg/L and HAA5 annual average less than or equal to 0.030mg/L for two consecutive years OR TTHM annual average less than or equal to 0.020 mg/L and HAA5 annual average less than or equal to 0.015mg/L for one year one sample per treatment plant per three year monitoring cycle at distribution system location reflecting maximum residence time during month of warmest water temperature, with the three-year cycle beginning on January 1 following quarter in which system qualifies for reduced monitoring.

1TOC sampling must be performed in accordance with 290.112(c)(2)(C) of this title (relating to Total Organic Carbon (TOC))