Lead in Drinking Water: Sources, Risks, and How to Test

Why lead in water is its own problem

Most people associate lead exposure with paint chips on old window sills. But lead in drinking water is a separate exposure pathway, and unlike paint, it doesn't depend on the home being painted poorly. The lead in your water almost always comes from the pipes and fittings between the street and your tap.

Your water utility doesn't add lead. It enters at the connection — the service line that runs from the water main to your home, and the solder used inside your walls.

Where it comes from

Service lines: Roughly 9 million lead service lines remain in the U.S. — the EPA is requiring all of them be replaced within 10 years under the 2024 Lead and Copper Rule Improvements. If you don't know whether your service line is lead, your utility is now required to tell you.

Solder: Lead solder was legal in residential plumbing until 1986. Any home built before then likely has lead solder somewhere in the system.

Fixtures: Faucets and valves labeled "lead-free" before 2014 could legally contain up to 8% lead. After 2014, that dropped to 0.25%.

Galvanized pipes: Older galvanized iron pipe downstream of lead pipe can absorb lead over decades, then release it long after the lead pipe is gone.

Who's at higher risk

Children are the primary concern. Lead affects developing brains at concentrations that don't visibly affect adults. The American Academy of Pediatrics and the CDC have both stated there is no safe level of lead exposure for children.

Pregnant people are also higher-risk: lead crosses the placenta and stored lead in the mother's bones is mobilized during pregnancy.

Renters and lower-income households are statistically more likely to live in pre-1986 housing and less likely to have had recent plumbing upgrades.

The numbers that matter

EPA action level: 15 parts per billion (ppb) at the tap. This is dropping to 10 ppb under the Lead and Copper Rule Improvements (LCRI), with full enforcement by 2027.

MCLG (Maximum Contaminant Level Goal): zero. The EPA itself acknowledges there is no safe level.

FDA bottled water standard: 5 ppb.

AAP recommendation for schools: less than 1 ppb at any tap used for drinking water.

How to test correctly

Lead levels in tap water spike after water has sat in pipes overnight. A test taken after running the tap for a minute will likely understate the problem.

Best practice is a "first-draw" sample — collected the first time the tap is used after at least 6 hours of stagnation. This catches the worst-case exposure, which is exactly what you'd consume making coffee or a baby's bottle first thing in the morning.

A "flushed" sample taken after running the water for 1-3 minutes is useful as a comparison — it tells you whether your service line or your indoor plumbing is the source.

What to do if you find lead

Above 1 ppb: worth addressing if children or pregnant people drink the water.

Above 10-15 ppb: take action. Stop drinking and cooking with the water until you have filtration in place. Run the tap for 1-3 minutes before use as a temporary measure.

Filtration: Look for filters certified to NSF/ANSI 53 for lead reduction (faucet-mount, pitcher, or under-sink). Reverse osmosis is the most effective. Whole-house carbon filters generally do NOT remove lead — read the certification carefully.

Long-term: Replace the lead service line if you have one. Your utility may share the cost under the new federal program.