15A NCAC 18A .2535 WATER QUALITY STANDARDS
Whenever a public swimming pool is open for use, water quality shall be maintained in accordance with the following:
(1) The chemical quality of the water shall be maintained in an alkaline condition at all times with the pH between 7.2 and 7.8.
?(2) The clarity of the water shall be maintained such that the main drain grate is visible from the pool deck at all times.
(4) When chlorine is used as the disinfectant, a free chlorine residual of at least one part per million (ppm) shall be maintained throughout the pool whenever it is open or in use. Pools that use chlorine as the disinfectant must be stabilized with cyanuric acid except at indoor pools or where it can be shown that cyanuric acid is not necessary to maintain a stable free chlorine residual. The
cyanuric acid level shall not exceed 100 parts per million.
(6) When chlorine or bromine are used as the disinfectant, automatic chemical feeders shall be used. Automatic chlorine or bromine feeders shall be manufactured and installed in accordance with NSF/ANSI Standard number 50. Automatic chlorine and bromine feeder pumps shall be
automatically prevented from operating when the circulation pump is not in operation.
(10) Test kits or equipment capable of measuring disinfectant level, pH, and total alkalinity must be
maintained at all public swimming pools. Pools using cyanuric acid or chlorinated isocyanurates
must have a test kit capable of measuring cyanuric acid levels.
(12) Water temperature in heated swimming pools shall not exceed 90 degrees Fahrenheit (32 degrees
Celsius) and in heated spas shall not exceed 104 degrees Fahrenheit (40 degrees Celsius).