What are the allowable min/max PPM ranges for acceptable chlorine levels in swimming pools and spas? Is there a documented requlation that states this?
The US EPA and Association of Pool and Spa Professionals (APSP) recommend a level of 1 to 4 ppm for pools and 2 to 5 ppm for spas. Another organization the National Swimming Pool Foundation (NSPF) sites a 1 to 5 ppm acceptable range (2 to 4 ppm ideal) for pools and 2 to 10 ppm for spas (3 - 5 ppm ideal). The state/local health department will ultimately have authority over which range is appropriate for their region.