When A Representative Sample Of Service Lines Reveals Zero Lead, What Can You Say?

It’s easy to find evidence for a risk of lead exposure from water service lines: once you find a lead service line, you know there is some risk. But how do we show that there isn’t a meaningful risk of lead in our water system?

In some communities, water utility personnel with decades of experience have never come across a lead service line in their water system. They can then go on to complete hundreds of hydrovac inspections and a representative sampling of their tens of thousands of water service lines, and still not find any lead. Such scenarios are more often the case in states with many newer communities, where lead service lines have been less common. Those communities rightfully wonder when it’s safe to stop digging holes and focus their limited resources elsewhere to better protect public health equitably.

Given that BlueConduit’s data science, including its predictive modeling, has been used to help many communities accurately estimate how many lead service lines they have and where these are likely to be located, it’s fair to ask a few questions, which we have heard across water utilities, engineering firms, and state regulators alike, and which we will address here.