New Map Shows Areas with Lead Violations and High Lead Levels in Tap Water

NRDC has produced a map showing the populations of people who get their tap water from community water systems (CWSs¹) that detected elevated lead levels, based on new data from the U.S. Environmental Protection Agency (EPA). Roughly 91 percent of the U.S. population, or about 310 million people, relies on CWSs for drinking water. The map shows the populations that got their water from utilities with health-based violations² of the EPA’s lead in drinking water rule and provides information on actual lead levels in tap water. It covers the period from January 2021 through December 2024. The map shows the congressional districts affected, using the EPA’s new water system boundary data as well as the CWS boundaries. Previous NRDC maps showed where lead pipes were thought to exist but did not include lead violations data or detailed information on the actual lead levels in tap water. 

There is no safe level of lead exposure. The EPA, U.S. Centers for Disease Control and Prevention, American Academy of Pediatrics, World Health Organization, and other experts all agree on this—so only zero parts per billion (ppb) of lead is safe in tap water. Lead exposure can cause permanent damage to the developing brains of fetuses and children, resulting in a loss of IQ points, attention deficit hyperactivity disorder, learning problems, and low birth weight and related complications; in adults, it can adversely affect the kidneys and reproductive systems, cause heart disease, and lead to fatal heart attacks, among other harms. Yet these new maps and data show millions of Americans are drinking water from systems that contain lead.

Overall, the EPA’s data demonstrate that large populations of people across the nation got their water from CWSs that have been detecting significant lead levels. The EPA reports the 90th percentile lead levels³ for each water system. 

Of course, since these are 90th-percentile levels, not everyone served by a water system was drinking water exceeding the levels noted below, though a significant portion of the people served by that system were. Many homes have lead service lines or lead-containing indoor plumbing, and lead levels at a single tap can vary significantly from day to day because lead is intermittently released into your tap water. So, the only way to know for sure what lead levels are in a home is to repeatedly test it. With these caveats, these data show that for at least some of the time during 2021–2024:

• 251.2 million people’s systems detected lead at or above the American Academy of Pediatrics’ recommended maximum level for children in school of 1 ppb—that’s 81 percent of the U.S. population served by community water systems.
• 112.3 million people got their water from systems that detected lead at or above the 5 ppb lead level that is the maximum allowed in bottled water—or 36 percent of the population served by these water systems.
• 44 million people got their water from systems detecting lead at or above the EPA’s new 10 ppb lead action level⁴ (which becomes effective in 2027)—or 14 percent of the population served by these systems.
• 12.9 million people got their water from systems detecting lead at or above the EPA’s current lead action level of 15 ppb (which remains in effect until 2027)—or about 4 percent of the population served by these systems.

In addition, a total of 72.6 million people across the nation (about 23.5 percent of the population served by community water systems) got their water from systems that had what the EPA classifies as a “health-based violation” for lead per its existing Lead and Copper Rule during this 2021–2024 period. 

Earlier NRDC maps have highlighted the location of lead service lines in communities across the country, or showed locations where EPA data indicated that lead in tap water ranged from 10–15 ppb. Our new analysis and data show the full range of lead levels detected from 2021–2024, as well as the health-based lead violations during this period, which have not previously been mapped or publicly analyzed. We mapped the EPA’s older lead violations data from 2018–2020 in an earlier publication; our new map provides more recent lead violations data as well as new 90th percentile lead levels for the past four years; it also, for the first time, breaks out this information by congressional district. 

The Lead and Copper Rule Improvements adopted by the EPA in fall 2024 required virtually every lead water pipe to be replaced within 10 years. The Trump administration has not committed to upholding that rule. The data presented here underscore the importance of reducing exposure to lead pipes that contaminate drinking water, which will go a long way toward improving the health of millions of people across the nation.  

NOTE: This map is best viewed on a desktop/laptop/tablet; on mobile, the map is best viewed in Chrome.

These tables highlight that some congressional districts have high numbers of people served by water systems that have lead issues. 

The data also show that some congressional districts have disproportionately high numbers of people served by water systems that found lead in their tap water at some point between 2021 and 2024. 

These tables reinforce the importance of removing lead from our drinking water and of carrying out the EPA’s 2024 Lead and Copper Rule Improvements, including the requirement that virtually all lead service lines be removed in a decade. The tables also highlight the need for additional federal investment in water infrastructure, including funding to help municipalities remove their lead pipes. The Bipartisan Infrastructure Law, enacted in 2021, provided $15 billion targeted for lead pipe removal, but these funds expire in 2026.

¹A “community water system” is defined as a system that supplies water to at least 25 people or 15 service connections year-round.

²A “health-based violation” for lead is an EPA-designated category of violations of the agency’s Lead and Copper Rule that can include a failure to adopt or implement requirements to treat the water to optimize its control of corrosion. Such corrosion control is key to reducing lead leaching or flaking off from lead service lines or indoor lead-containing plumbing. These violations can also include the failure to remove lead service lines when the system was required to do so due to elevated lead levels. A high level of lead in tap water, and even exceedance of the EPA’s lead action level (a term discussed below), is not in an of itself a violation of the EPA rule. Only if a water system exceeds EPA’s lead action level and then fails to take certain corrective measures required by the rule, does the water system incur a health-based violation. 

³The EPA’s Lead and Copper Rule requires water systems to calculate and report their 90th percentile level of lead. For example, if the system tests 100 homes, it takes the 10th-highest lead level detected and reports that to its state, and this is entered into the EPA’s database. The 90th percentile level is an indicator of how high the system’s lead levels are and of the effectiveness of the water system’s efforts to control how corrosive its water is, and thus, how much lead it releases into tap water.    

⁴The EPA’s lead action level of 10 ppb, established in the Lead and Copper Rule Improvements that were issued in October 2024, is the level at which water systems must take additional steps to address their elevated lead levels. If a water system’s 90th percentile lead level exceeds the lead action level of 10 ppb, the system must take certain additional measures. These include installing or re-optimizing corrosion control and providing additional public notification and public education regarding the high lead levels. The EPA is clear that the lead action level is not a “safe” level—it is a measurement of the effectiveness of corrosion control. The EPA confirms that only zero lead is safe. As noted above, the previous lead action level was 15 ppb, which remains in effect until 2027.

This page was originally published on April 4, 2024, and has been updated with new information and links.