NSF/ANSI 42 covers aesthetic effects like chlorine taste and odor. NSF/ANSI 53 covers health-effect claims such as lead and some PFAS-related claims. NSF/ANSI 58 covers reverse-osmosis systems. NSF/ANSI 401 covers emerging contaminants.
Primary directories: NSF DWTU, IAPMO PLD, WQA certified products.