North Carolina Administrative Code › Title 15A - Environmental Quality › Chapter 18 - ENVIRONMENTAL HEALTH › Subchapter C - WATER SUPPLIES › Section .1300 - OPERATION OF PUBLIC WATER SUPPLIES › Section 18C .1302 - TESTS, FORMS AND REPORTING

Current through Register Vol. 39, No. 2, July 15, 2024
(a)
				  Required tests. If a public water system uses disinfectants or other chemicals
				  for the treatment of water, residual disinfectant tests and other applicable
				  water quality tests required by this Subchapter shall be made during every
				  oversight visit to the facility required by Rule .1303 of this Section.
				  Residual disinfectant concentrations shall be maintained in accordance with
				  15A NCAC
				  18C .2002 and
				  18C .2201 and shall be tested as
				  follows:
(1) Residual disinfectant tests at
				  the entry point. For systems providing treatment, residual disinfectant
				  concentrations shall be measured in the water entering the distribution system
				  by the operator during every visit required by Rule .1303(a) of this
				  Section.
(2) Residual disinfectant
				  tests in the distribution system shall be performed as follows:
(A) Residual disinfectant concentrations
				  shall be measured weekly at locations that represent maximum residence time of
				  the water in the distribution system or at other locations with high water age.
				  These locations shall be designated on the sample siting plan required under
				  15A NCAC
				  18C .1534. The number of required weekly
				  tests is shown in Table A below. Samples collected on the same day must be
				  collected from different locations.
Table A: Measurement Requirements for Residual Disinfectant
					 Concentrations and Chloramine Operational Parameters
Distribution System Classification according to
15A NCAC 18D
								.0205(b)
Minimum Number of Samples Per Week
D
1
C
3
A and B
5
(B) Distribution systems classified as C or D
				  in Table A may request the Department to reduce the requirements for measuring
				  residual disinfectant concentrations in the distribution system at the
				  locations that represent maximum residence time or other locations with high
				  water age as required in Part (a)(2)(A) of this Rule. The request shall be in
				  writing and shall demonstrate to the Department that the residual disinfectant
				  concentrations measured at the entry point in accordance with Subparagraph
				  (a)(1) of this Rule are sufficient in providing the minimum residual
				  disinfectant concentrations required under
				  15A NCAC
				  18C .2002 and
				  18C .2201. The Department shall
				  consider the presence of continuous monitoring, size and configuration of the
				  distribution system, magnitude of disinfectant degradation and results of
				  performance studies.
(3)
				  Chloramine Operational Parameters. When ammonia and chlorine are applied
				  disinfectants, the system shall measure analytical parameters pertinent to the
				  operation as follows:
(A) Water entering the
				  distribution system. Parameters to be measured shall, at a minimum, include
				  total chlorine, monochloramine, free ammonia, and pH and shall be performed
				  daily, while the treatment facility is in operation.
(B) Water in the distribution system.
				  Parameters to be measured shall, at a minimum, include total chlorine,
				  monochloramine, free ammonia, and pH and shall be measured no less often than
				  denoted in Table A.