Lead in American Tap Water: What the 2026 Data Shows

There is no safe level of lead in drinking water, according to federal health agencies. Yet 1,113 community water systems in the United States are currently delivering water that exceeds the EPA's 15-parts-per-billion lead action level — the threshold at which a utility must take corrective steps.

An AGUACYCLE review of EPA's Safe Drinking Water Information System shows the exceedances are far from evenly spread. A small group of states carries most of the burden, and the reasons trace back more than a century.

Pennsylvania and New Hampshire lead the list

Pennsylvania has the most systems over the lead action level by a wide margin: 390. New Hampshire is second with 211. Together those two states account for more than half of all lead action-level exceedances in the country. They are followed by Michigan with 53, California with 37, Arkansas with 35, and New York with 29.

The concentration in the Northeast and industrial Midwest is not a coincidence. These are among the oldest plumbed regions in the country, where the lead service lines that connect homes to water mains were installed when lead was the standard material and have never been fully replaced.

Old pipes, small systems

Lead rarely originates in the water leaving a treatment plant. It leaches in on the way to the tap, from lead service lines, lead solder, and brass fixtures inside the distribution system and the home. That makes the problem a function of infrastructure age and corrosion control rather than source-water quality — which is why states with the oldest housing stock and the most legacy lead pipe show up at the top.

Small systems are especially exposed. Optimized corrosion control — adjusting water chemistry so it stops dissolving lead from pipes — requires monitoring and expertise that under-resourced systems struggle to maintain. When that treatment slips, lead levels climb.

The Lead and Copper Rule Revisions

Lead is now the single most active area of drinking-water compliance. The Lead and Copper Rule Revisions are associated with 4,625 systems' compliance activity in the data — the largest of any rule category — reflecting tightened requirements to inventory lead service lines, sample more rigorously, and plan for replacement.

That activity is the leading edge of a national push to find and pull every lead service line in the ground, a project expected to run for years and cost tens of billions of dollars. The 1,113 systems currently over the action level are the visible failures; the 4,625 figure is the much larger universe of systems now being forced to prove their water is safe rather than assume it.

For households, the practical takeaway is unchanged: in older homes, especially in the Northeast and Midwest, requesting a tap-water lead test and asking the local utility about service-line material remain the most reliable ways to know what is coming out of the faucet.