NSF follows the American National Standards Institute (ANSI) standard development process. Members of public health, industry and user representatives get together and form these standards to make sure that they give us the best. Here are a few prevalent standards: NSF 53: Involves material security, structural integrity, and contaminates reduction capacity claims.  NSF 58: For lead and other general contaminants elimination. NSF 42: Signifies a water filter's ability to remove chlorine from water NSF 401: It rates the ability of a water filter system to reduce up to 15 specific contaminants. NSF 372: Certification for having lead-free fittings and components. NSF P473: Guarantees that it reduces PFOA and PFOS chemicals in water, and harmful artificial chemicals.