Lead‐contaminated water from brass plumbing devices in new buildings

Abstract

Lead contamination of potable water in new buildings on the University of North Carolina at Chapel Hill campus was traced to corrosion of inline brass plumbing devices. Commissioning procedures to remove lead sediment and hasten brass passivation were developed. Forensic evaluation of a water fountain dispensing > 100 μg/L lead in flushed water after commissioning led to the discovery of ball valves containing brass with > 8% lead by weight on exterior surfaces and > 18% on surfaces contacting the water. Removing these ball valves resolved the lead problems, bench‐testing verified that the valves had a high lead‐leaching propensity, and subsequent surveying of ball valves in three buildings found 22% contained exterior surface lead > 8%. Significant lead‐leaching problems can occur when: (1) the water is at least moderately corrosive to brass, (2) brass with a high lead content is present, and (3) premise plumbing lines have relatively low water demand.