Lead variability testing in Seattle Public Schools

A field‐testing program was conducted in Seattle (Wash.) Public Schools (SPS) to assess the variability of lead at drinking water sources (i.e., fountains) after implementation of a lead remediation program. A total of 768 samples—384 first‐draw and 384 flushed samples—were collected from 48 drinking water fountains during a two‐month period. Results showed the mean lead concentration to be 3 μg/L, which was notably less than the 21 μg/L measured before remediation in SPS. Twelve samples (1.6%) had lead concentrations > 10 μg/L, four samples (0.5%) showed lead levels > 20 μg/L, and no samples had lead concentrations > 30 μg/L. The highest lead concentrations and greatest variability occurred in samples from end‐use plumbing configurations consisting of standard brass materials (~3–8% lead), whereas relatively low lead concentrations and variability were observed for sources with low‐lead bubblers and components. This study demonstrated that the remediation program successfully and reliably lowered lead levels in SPS drinking water.