AWWA WQTC64084

A field testing program was conducted in Seattle Public Schools to assess the variability of lead (Pb) at drinking water sources after implementing a lead remediation program. Four different source configurations were identified as typical end-use plumbing. Twelve drinking water sources were selected based on statistical correlations to represent each configuration for a total of forty-eight locations tested. Sixteen samples (8 first draw and 8 flushed samples) were collected from each source after overnight standing. Results indicate that 12 samples out of a total of 768 (1.6%) exhibited Pb >10 µg/L, 4 samples (0.5%) exhibited Pb >20 µg/L, and none were greater than 30 µg/L. The highest Pb levels and greatest variability occurred in samples from configurations with standard brass materials (up to 8% Pb). Relatively low Pb concentrations and variability were observed for sources with low-lead bubblers and new components. The mean concentration of Pb for all samples was 2.8 µg/L after remediation compared to 20.8 µg/L before remediation. Includes 11 references, tables, figures.