Water systems over the new 10 ppb lead action level

It is the lead concentration that triggers extra steps by a water system when more than 10% of tap samples from high-risk homes exceed it. It is 15 parts per billion today and drops to 10 ppb when the Lead and Copper Rule Improvements take effect in November 2027. It is not a health-based safe level; EPA says there is no safe level of lead.

Utilities sample taps at homes most likely to have lead, often homes with lead service lines. The 90th-percentile value is the level that 90% of those samples were at or below. A high value means lead is reaching some taps; it does not mean every home has that much lead.

It must notify customers quickly, step up public education and sampling, review or install corrosion control treatment, and keep replacing lead service lines. Under the new rule, systems with repeated exceedances must also make certified lead filters available to customers.

Use a filter certified to NSF/ANSI 53 for lead for drinking and cooking, ask your utility for a free tap test, check whether your service line is lead, and look up your utility's replacement program on this site.