The City of St. Clair Shores has 25,303 water customers. The City estimates that there are approximately 650 homes with lead service lines. In St. Clair Shores lead service lines are most commonly found in homes built between 1920 and 1950.
32 of those customers with known lead service lines were tested during September 2019. 4 of the 32 locations tested exceeded the 15 parts-per-billion (ppb) “Action Level” threshold, triggering the current Public Advisory. The city’s 90th percentile value for lead concentrations among sites tested was 21 ppb. The testing results shown that the “Action Level” exceedances were from samples taken from the lead water service lines.
Per the Lead and Copper Rule of the Michigan Safe Drinking Water Act, the city is required to periodically sample a number of water taps throughout its system for lead concentration levels. In 2018, the sampling protocol for this routine sampling changed to require multiple samples at each sample location and to exclusively target locations served by lead water service lines. The intention of this change was to better detect lead.
According to the rule, if approximately 10% of sites sampled (90th percentile) indicate lead concentrations of 15 ppb or greater, the city is required to:
advise water customers of the results
provide tips on how to reduce lead exposure
increase community-wide sampling