South Carolina Code of Regulations › Chapter 61 - DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL › Subchapter 61-58.15 - Stage 2 Disinfection Byproducts Requirements › Section 61-58.15.E - Reduced Monitoring

Current through Register Vol. 48, No. 6, June 28, 2024
(1)
			 Systems may reduce monitoring to the level specified in this paragraph (1) any
			 time the LRAA is less than or equal to 0.040 mg/L for TTHM and less than or
			 equal to 0.030 mg/L for HAA5 at all monitoring locations. Only data collected
			 under the provisions of R.61-58.15 or R.61-58.13 may be used to
			 qualify for reduced monitoring. In addition, the source water annual average
			 TOC level, before any treatment, must be less than or equal to 4.0 mg/L at each
			 treatment plant treating surface water or ground water under the direct
			 influence of surface water, based on monitoring conducted under either
			 R.61-58.13.C(2)(a)(vi)
			 or R.61-58.13.C(4). Systems on reduced monitoring under this section that are
			 required to monitor quarterly must take dual sample sets every 90 days.
(a) Subpart H systems serving less than 500
			 people may not reduce monitoring.
(b) Subpart H systems serving between 500 and
			 3,300 people and meeting the criteria in this paragraph (1) may reduce
			 monitoring to one (1) TTHM sample per year taken at the location and during the
			 quarter with the highest TTHM single measurement, and one (1) HAA5 sample per
			 year taken at the location and during the quarter with the highest HAA5 single
			 measurement. One (1) dual sample set per year may be taken if the highest TTHM
			 and HAA5 measurements occurred at the same location during the same
			 quarter.
(c) Subpart H systems
			 serving between 3,301 and 9,999 people and meeting the criteria in this
			 paragraph (1) may reduce monitoring to one (1) dual sample set per year taken
			 at the location and during the quarter with the highest TTHM single
			 measurement, and one (1) dual sample set per year taken at the location and
			 during the quarter with the highest HAA5 single measurement.
(d) Subpart H systems serving between 10,000
			 and 49,999 people and meeting the criteria in this paragraph (1) may reduce
			 monitoring to two (2) dual sample sets per quarter taken at the locations with
			 the highest TTHM and HAA5 LRAAs.
(e) Subpart H systems serving between 50,000
			 and 249,999 people and meeting the criteria in this paragraph (1) may reduce
			 monitoring to four (4) dual sample sets per quarter taken at the locations with
			 the two highest TTHM and two highest HAA5 LRAAs.
(f) Subpart H systems serving between 250,000
			 and 999,999 people and meeting the criteria in this paragraph (1) may reduce
			 monitoring to six (6) dual sample sets per quarter taken at the locations with
			 the three highest TTHM and three highest HAA5 LRAAs.
(g) Subpart H systems serving between
			 1,000,000 and 4,999,999 people and meeting the criteria in this paragraph (1)
			 may reduce monitoring to eight (8) dual sample sets per quarter taken at the
			 locations with the four highest TTHM and four highest HAA5 LRAAs.
(h) Subpart H systems serving 5,000,000 or
			 more people and meeting the criteria in this paragraph (1) may reduce
			 monitoring to ten (10) dual sample sets per quarter taken at the locations with
			 the five highest TTHM and five highest HAA5 LRAAs.
(i) Ground water systems serving less than
			 500 people and meeting the criteria in this paragraph (1) may reduce monitoring
			 to one (1) TTHM sample every third year taken at the location and during the
			 quarter with the highest TTHM single measurement, and one (1) HAA5 sample every
			 third year taken at the location and during the quarter with the highest HAA5
			 single measurement. One (1) dual sample set every third year may be taken if
			 the highest TTHM and HAA5 measurements occurred at the same location during the
			 same quarter.
(j) Ground water
			 systems serving between 500 and 9,999 people and meeting the criteria in this
			 paragraph (1) may reduce monitoring to one (1) TTHM sample per year taken at
			 the location and during the quarter with the highest TTHM single measurement,
			 and one (1) HAA5 sample per year taken at the location and during the quarter
			 with the highest HAA5 single measurement. One (1) dual sample set per year may
			 be taken if the highest TTHM and HAA5 measurements occurred at the same
			 location during the same quarter.
(k) Ground water systems serving between
			 10,000 and 99,999 people and meeting the criteria in this paragraph (1) may
			 reduce monitoring to one (1) dual sample set per year taken at the location and
			 during the quarter with the highest TTHM single measurement and one (1) dual
			 sample set per year taken at the location and during the quarter with the
			 highest HAA5 single measurement.
(l) Ground water systems serving between
			 100,000 and 499,999 people and meeting the criteria in this paragraph (1) may
			 reduce monitoring to two (2) dual sample sets per quarter taken at the
			 locations with the highest TTHM and HAA5 LRAAs.
(m) Ground water systems serving 500,000 or
			 more people and meeting the criteria in this paragraph (1) may reduce
			 monitoring to four (4) dual sample sets per quarter taken at the locations with
			 the two highest TTHM and two highest HAA5 LRAAs.