Lead
Also known as: Pb
Lead leaches from old pipes and fixtures, not the source water — which is why it varies house to house and why service-line replacement is the real fix.
Action level 0.015 mg/L (15 ppb). Lead has no safe level (MCL goal is zero). EPA sets a 0.015 mg/L action level on the 90th-percentile of tap samples; exceeding it triggers corrosion-control and lead-service-line work.
A potent neurotoxin. In children even low exposure can lower IQ, impair attention, and slow development; in adults it raises blood pressure and harms the kidneys. Effects are cumulative and irreversible.
Almost never in the source water — lead leaches from corroding lead service lines, brass fixtures, and lead solder in home and street plumbing.
Use a filter certified to NSF/ANSI 53 for lead, flush taps that have sat unused, use cold water for cooking, and push your utility to replace lead service lines. Boiling does NOT remove lead.
Source: EPA Safe Drinking Water Information System (SDWIS) · 2026 Q1
Lead is the contaminant most associated with U.S. drinking-water crises, from Flint, Michigan to Newark, New Jersey. Unlike most contaminants it usually isn't present where the water is treated — it dissolves into the water from lead service lines and household plumbing on the way to the tap.
Because the exposure is plumbing-driven, lead levels can differ dramatically between two houses on the same street, and a system's 90th-percentile sample is the regulatory yardstick. When that figure crosses 0.015 mg/L, the utility must intensify corrosion control and accelerate lead-service-line replacement.
The 2021 Lead and Copper Rule Revisions and the 2024 Lead and Copper Rule Improvements push toward full replacement of an estimated 9+ million lead service lines nationwide — the single biggest driver of lead-related compliance activity in our data.
States with the most lead violations
Community water systems with a related health-based violation since 2016.
| # | State | Systems |
|---|---|---|
| 1 | Texas | 1183 |
| 2 | California | 522 |
| 3 | Oklahoma | 475 |
| 4 | North Carolina | 340 |
| 5 | Wisconsin | 255 |
| 6 | Illinois | 242 |
| 7 | Louisiana | 213 |
| 8 | Mississippi | 209 |
| 9 | Michigan | 194 |
| 10 | Arizona | 185 |
| 11 | Florida | 180 |
| 12 | New Mexico | 173 |
Common questions
What is the EPA limit for lead in drinking water?
Action level 0.015 mg/L (15 ppb). Lead has no safe level (MCL goal is zero). EPA sets a 0.015 mg/L action level on the 90th-percentile of tap samples; exceeding it triggers corrosion-control and lead-service-line work.
Is lead in drinking water dangerous?
A potent neurotoxin. In children even low exposure can lower IQ, impair attention, and slow development; in adults it raises blood pressure and harms the kidneys. Effects are cumulative and irreversible.
Where does lead in water come from?
Almost never in the source water — lead leaches from corroding lead service lines, brass fixtures, and lead solder in home and street plumbing.
How do I remove lead from my water?
Use a filter certified to NSF/ANSI 53 for lead, flush taps that have sat unused, use cold water for cooking, and push your utility to replace lead service lines. Boiling does NOT remove lead.
Which states have the most lead violations?
Across U.S. community water systems, 5,736 have had a related health-based violation since 2016, led by Texas with 1183.
Source: EPA — National Primary Drinking Water Regulations
Source: EPA — Basic Information about Lead in Drinking Water