Iron Clogging of Lead-Certified Point-of-Use Pitcher Filters

Point-of-use household water filters (POU filters) are increasingly used to protect consumers from lead in drinking water, but there have been anecdotal reports of premature failure due to clogging when iron is present. To evaluate this concern in relation to lead removal and treatment costs, POU pitcher filters were exposed to water conditions containing lead and/or iron and tested to 100% of their rated capacity or until they clogged. Iron levels above the 0.3 mg/L Secondary Maximum Contaminant Level (SMCL) resulted in rapid clogging, affecting both treatment costs and consumer satisfaction. At 0.3 mg/L iron (Fe), half of the six POU filters tested clogged prematurely between 38% and 68% of the rated capacity. At 1.0 mg/L Fe, four out of six POU filters tested clogged prematurely, and all clogged prematurely at 20 mg/L.