Lead in drinking water

What it is

Lead is a toxic metal. The World Health Organization puts it plainly: there is no level of exposure to lead that is known to be without harmful effects.^[1] EPA agrees — which is why its health goal for lead in drinking water is zero.^{[2, 3]}

Lead rarely starts in the river, lake or aquifer your water comes from. It's usually picked up on the way to your glass.

How it gets into water

According to EPA, lead enters drinking water when plumbing materials that contain lead corrode — especially where water has high acidity or low mineral content. The main culprits are lead service lines (the pipes connecting a building to the water main), brass or chrome-plated brass faucets and fixtures, and lead solder. Homes built before 1986 are more likely to have lead pipes, fixtures and solder.^[2]

The federal government banned new lead pipes in 1986, but legacy pipes remain in the ground.^[4] With its latest data, EPA estimates there are about 4 million lead service lines across the country — roughly 3 million reported and 1 million listed as "unknown" that are predicted to be lead.^[5] That's why two homes on the same street can have very different water at the tap.

Health impacts

Children are most vulnerable. CDC says no safe blood lead level in children has been identified, and even low levels are associated with developmental delays, difficulty learning and behavioral issues.^[6] CDC lists damage to the brain and nervous system, slowed growth and development, learning and behavior problems, and hearing and speech problems among the effects — which can show up as lower IQ, trouble paying attention and underperformance in school.^[7]

CDC estimates that approximately 500,000 children in the United States have blood lead levels at or above its blood lead reference value of 3.5 micrograms per deciliter.^[8] Drinking water is one of several possible sources of lead exposure. If you're worried about a child's exposure, talk to your doctor about a blood lead test.

What the law says vs. what health science says

Lead is regulated differently from most contaminants. Instead of a maximum contaminant level, EPA uses a treatment technique with an action level. Today that action level is 15 parts per billion (ppb).^[3] The action level isn't a safety line — it's a trigger that requires a water system to take steps like improving corrosion control and informing the public. The health goal remains zero.

EPA's Lead and Copper Rule Improvements, finalized in October 2024, lower the action level to 10 ppb starting November 1, 2027, and require the vast majority of water systems to replace lead service lines within 10 years.^{[4, 9]} The rule also changes how homes are sampled: at sites with lead service lines, systems must collect both first-liter and fifth-liter samples and use the higher result.^[9]

Testing at the tap is limited by design. Depending on system size, the rules call for samples from as few as 5 to as many as 100 sites, collected every six months at most — and as rarely as once every three or nine years for systems that qualify for reduced monitoring.^[10] That's a snapshot, not a live feed.

What you can do

Find out what your service line is made of. Water systems are building service line inventories under the new rule, with a baseline inventory due by November 1, 2027.^[9] Ask your water system what's on record for your address.
Use cold water for drinking, cooking and making baby formula, as CDC recommends.^[11]
Don't count on boiling. Boiling water does not remove lead.^[2]
Consider a certified filter. CDC advises using a filter certified to remove lead — look for NSF/ANSI Standard 53 — and keeping up with cartridge changes.^[11]
Talk to your doctor about blood lead testing for young children if you have concerns.
Check your AquaScore™ to see how the water at your address compares to the legal limit and the health goal.