Extended Sentinel Sampling

Why it Matters: The Extended Sampling Program is a continuation of the original Sentinel Sampling Program that uses a smaller pool of participants (170 or so). It also includes sampling only once a month. The Extended Sentinel sampling program is focused on areas most likely to have high levels of lead and/or copper. All the homes with known lead service lines were encouraged to continue participation. The Extended Sentinel sites were selected based on homes with one or more of the following criteria:

  • Lead service lines
  • Service lines replaced under the "Fast Start" pilot service line replacement program
  • High lead results for copper or galvanized lines during the original sentinel sampling
  • Geographically distributed across the city
  • Areas with predicted elevated blood lead levels
  • Homes built between 1983-1988 when lead solder was used more frequently with copper interior plumbing

Metric: The percent of Extended Sentinel test samples at or below 15 ppb lead. No samples were collected in October 2016, December 2016, or January 2017.