Lead in Drinking Water: Sources, Testing and Filters That Work

Most lead in US tap water doesn’t come from the treatment plant. It comes from the pipes between the water main and your glass.

Short answer: lead gets into drinking water when plumbing that contains lead corrodes. The biggest source, where one exists, is a lead service line, the pipe connecting your home to the main. Without one, the usual sources are lead solder and brass or chrome-plated brass faucets and fittings. The EPA’s health goal for lead in drinking water is zero, because no safe level is known. The practical steps are simple: find out whether your home has a lead service line, test the water at the taps you drink from, use only cold water for drinking and cooking, and if lead is a real possibility in your home, use a filter certified for lead reduction.

How does lead get into tap water?

According to the EPA’s basic guide to lead in drinking water, lead enters water as plumbing materials corrode, and that happens more readily when water is acidic or low in minerals. There are three main places it can come from:

• Lead service lines. Where they’re present, they’re typically the biggest source. They’re more likely in older cities and in homes built before 1986.
• Lead solder joining copper pipes in older plumbing.
• Faucets and fixtures made of brass or chrome-plated brass.

How much lead ends up in your glass depends on water chemistry, temperature, wear on the pipes, how long water has been sitting in them, and the protective scale inside. That’s why two homes on the same street can get very different results.

“Lead-free” plumbing isn’t literally lead-free. Under the Safe Drinking Water Act it now means a weighted average of no more than 0.25% lead on the surfaces that touch water in pipes, fittings and fixtures, and 0.2% in solder and flux, per the same EPA page.

If you’re on a private well, the same plumbing sources apply, but no utility samples your taps for you. Our well water testing guide covers what to test for.

Is any level of lead in water safe?

No safe level has been identified. The EPA sets the maximum contaminant level goal for lead in drinking water at zero, and its Lead and Copper Rule Improvements page states plainly that there is no safe level of lead exposure. The CDC says the same about children: its childhood lead poisoning prevention overview states that no safe blood lead level in children has been identified.

That doesn’t mean one glass with a trace of lead will hurt you. It means there’s no threshold known to be harmless, so the goal is to keep exposure as low as you reasonably can, especially for young children and during pregnancy.

Water is one source among several. Paint, dust, soil and some imported products also expose people to lead. The EPA estimates drinking water can make up 20% or more of a person’s total lead exposure, and 40% to 60% for infants who mostly drink formula mixed with tap water.

What does lead do to health?

Evidence rating: strong. That lead harms children’s development, even at low blood levels, is the position of the CDC, ATSDR and EPA and is backed by large studies. What’s harder to pin down is how much risk a given amount of lead in your water adds, because studies measure lead in blood, which comes from all sources combined.

In children. The CDC’s page on lead exposure symptoms and complications lists damage to the brain and nervous system, slowed growth and development, learning and behavior problems, and hearing and speech problems, which can show up as lower IQ, shorter attention span and poorer school performance. Most children have no obvious symptoms, so a problem can go unnoticed. The ATSDR’s ToxFAQs on lead explains why children are more vulnerable: their nervous system is still developing.

The low-level finding rests on studies like an international pooled analysis in Environmental Health Perspectives. It combined data on 1,333 children from seven long-term cohort studies, followed from birth or infancy to ages 5 to 10, and compared IQ scores with blood lead. After adjusting for other factors, higher blood lead went with lower IQ, and children whose blood lead never reached 7.5 µg/dL showed a larger IQ loss for the same increase than children with higher levels. A 2019 correction fixed data errors in one cohort; the corrected estimates are about 6.7 IQ points lower as blood lead rises from 2.4 to 30 µg/dL, and 3.8 points from 2.4 to 10 µg/dL, and the authors say the conclusions didn’t change. The limits: these are observational studies that show an association, and they measured lead from every source, not from water specifically.

Water can move children’s blood lead levels, though. A study of children under 5 in Flint, Michigan compared blood tests from 2013 with tests from 2015, after the city switched to a more corrosive water source without adequate corrosion control. The share of children with elevated blood lead rose from 2.4% to 4.9%; neighborhoods with the highest water lead levels saw a 6.6% increase, and there was no significant change outside the city. It’s a before-and-after comparison, not a trial, but it shows a change in water chemistry reaching children’s blood.

During pregnancy. The EPA notes that lead stored in a mother’s bones can be released during pregnancy and cross the placenta, which can reduce fetal growth and cause premature birth. Lead can also pass into breast milk. ATSDR adds that exposure to high levels of lead in pregnancy may cause miscarriage.

In adults. The EPA lists cardiovascular effects, higher blood pressure, decreased kidney function and reproductive problems. ATSDR notes that lead can affect almost every organ and system in the body, with the nervous system as the main target.

If you’re worried that you or your child has been exposed, talk to your healthcare provider. The CDC says a blood lead test is the best way to tell whether someone has been exposed, and a provider can decide whether one is needed. The CDC uses a blood lead reference value of 3.5 µg/dL to flag children whose levels are higher than most.

What is the Lead and Copper Rule?

Lead is regulated differently from most contaminants. Since 1991, the EPA’s Lead and Copper Rule has used a treatment technique instead of a legal maximum (an MCL). Utilities have to control corrosion, sample water at customers’ taps, and act if lead is too high. The trigger is the action level: if more than 10% of the homes sampled (the 90th percentile) are above it, the utility has to take steps such as adjusting corrosion control and informing the public.

One thing that confuses people: the action level is not a health limit. The EPA’s final rule in the Federal Register says it “is not a health-based number.” It’s a yardstick for whether corrosion control is working. Water below it isn’t automatically safe, and a utility above it isn’t in violation as long as it takes the required steps.

What changed with the 2024 Lead and Copper Rule Improvements?

In October 2024 the EPA finalized the Lead and Copper Rule Improvements (LCRI), published in the Federal Register on October 30, 2024. The rule took effect on December 30, 2024, and most of its requirements apply to water systems from November 1, 2027. The main changes, from the rule itself:

• Lead pipe replacement within 10 years. Water systems must replace all lead service lines, and certain galvanized lines that are or ever were downstream of a lead line, under their control within 10 years of the compliance date, whatever their lead test results. A few systems can get more time in limited circumstances. Where the pipe runs on private property, whether the utility can replace that part depends on state or local law, and in some places the owner’s consent.
• Lower action level. The lead action level drops from 15 ppb (0.015 mg/L) to 10 ppb (0.010 mg/L), and the separate “trigger level” from the 2021 revisions is removed.
• Better tap sampling. At homes with lead service lines, utilities must collect both the first and the fifth liter after water has sat in the pipes and use the higher result, to capture water that sat in the service line, not only in your faucet.
• Public inventories. Every system must make its service line inventory public and keep it updated, track lead connectors, and publish a replacement plan.
• Filters when lead stays high. Systems that exceed the lead action level three or more times in five years must step up outreach and make filters certified to reduce lead available to all consumers. After replacing a service line, a system must also provide a pitcher filter or point-of-use device with six months of replacement cartridges.

Some pieces already apply: since October 16, 2024, systems must keep a public service line inventory (online for systems serving more than 50,000 people) and notify customers about their line’s material. Until November 1, 2027, the rest follows the original rule, with the 15 ppb action level.

Status as of October 2026: the EPA still presents the LCRI as a final rule, with the November 1, 2027 compliance date. Its implementation tools page shows the agency still publishing guidance for the rule in 2026, including a resource guide released on June 29, 2026. We found no EPA notice delaying or withdrawing it. Rules can still change through new rulemaking or court decisions, so check the EPA’s LCRI page for the current status.

How do you find out if you have a lead service line?

Start with your water utility. It should already have an inventory classifying each service line as lead, galvanized requiring replacement, non-lead or unknown. Search its website for “service line inventory” or call with your address. If your line is listed as anything but non-lead, your utility should also have notified you.

You can also look yourself. The EPA’s Protect Your Tap guide walks you through it with pictures; all you need is a coin or key and a magnet. The idea, as an EPA research summary explains it: find the pipe where water enters your home and gently scratch it. Lead is dull, soft and non-magnetic and turns shiny silver when scratched. If the scratch is yellow-orange, the pipe is likely copper. If it’s shiny silver, it could be lead or galvanized iron, so try the magnet: if it sticks, the pipe is likely iron, not lead.

Two caveats. What you can see indoors is only one section of the line, and the material can change between the house and the main. And a non-lead service line doesn’t rule out lead from solder or faucets inside the house. Only a water test tells you what’s actually at your tap.

How do you test your water for lead?

You can’t see, taste or smell lead, so testing is the only way to know. The EPA recommends a certified laboratory; your state or local drinking water authority lists them, and tests usually cost about $15 to $100. Sample the faucets you drink from and follow the lab’s instructions exactly. Many utilities test on request, per the CDC, and some states and utilities help pay for testing or line replacement. Ask yours first.

Results can vary with time of day, season, sampling method and water flow, according to the CDC’s page on lead in drinking water, so one low result in a home with a lead service line isn’t a guarantee. Your utility’s annual Consumer Confidence Report also reports its lead sampling. Our guide to reading your water quality report shows where to find it and how to read the 90th percentile. For lab versus home kits, see our water testing hub.

What should you do in the meantime?

These steps come from the EPA and CDC and cost little or nothing:

• Use only cold water for drinking, cooking and making baby formula. Hot water can carry more lead.
• Don’t boil water to remove lead. Boiling doesn’t remove it.
• Flush your pipes before drinking when water has been sitting, by running the tap or taking a shower. How long depends on your plumbing, so ask your utility for its recommended flushing time.
• Clean your faucet aerators regularly, since lead particles can collect in them.
• Watch for nearby construction. The EPA notes that ground vibrations from it can release more lead from service lines.

Showering and bathing are fine, even when lead is above the action level: both the EPA and CDC say skin doesn’t absorb lead from water. If your utility or health department gives you specific instructions, follow theirs.

Do you need a filter for lead?

Maybe not. If your utility’s inventory lists your service line as non-lead, your plumbing is newer, and a certified lab finds no detectable lead at your drinking taps, a lead filter isn’t adding much. The CDC recommends filters for people with lead service lines, and that’s where they matter most: homes with a lead or unknown line, older plumbing with lead solder, a test that finds lead, or a household with an infant, a young child or someone pregnant while you wait for answers.

If you do get one, the certification matters more than the type:

• Look for NSF/ANSI 53 for lead reduction, or NSF/ANSI 58 if it’s a reverse osmosis system. NSF’s lead reduction listings explain that 53 is the standard for drinking water treatment units and 58 the one for reverse osmosis systems. Certified filters are tested with water containing 150 ppb of lead, beyond their claimed service life, at 20°C (68°F).
• Check the exact model. The EPA’s consumer tool for lead filters says to look for a filter that an accredited third-party certifier has evaluated for lead reduction to 5 ppb or less, and for Class I particulate reduction, under NSF/ANSI 53 and 42. Packaging and maker claims aren’t enough: look up the model and cartridge in the certifier’s own listing (NSF, WQA or IAPMO) and confirm lead is on it.
• Mind the limits. NSF notes that performance above 150 ppb hasn’t been evaluated, and certified units haven’t been tested at elevated temperatures. Run only cold water through them, as the EPA advises.
• Replace cartridges on time. A filter is certified for a set volume of water. Past that, it’s no longer doing what the listing says.

Pitchers, faucet and under-sink filters and reverse osmosis units can all carry lead certification; the water filters hub compares the types, and our reverse osmosis explainer covers that technology. A filter is a stopgap, though. The permanent fix for a lead service line is replacing it.

Bottom line

Lead in tap water usually comes from plumbing, not the utility’s source, and no safe level is known, so keep exposure low. Check your utility’s service line inventory, test your drinking taps through a certified lab, use cold water and flush when water has been sitting. If you have a lead or unknown service line, older plumbing or a test that finds lead, use a filter whose exact model is certified to NSF/ANSI 53 (or 58 for reverse osmosis) for lead until the source is fixed. If your line isn’t lead and your test is clean, you likely don’t need a lead filter. As of October 2026, the 2024 federal rule has utilities replacing lead lines within 10 years of November 2027, with a 10 ppb action level from that date. For other contaminants, see what’s in your water and our guide to PFAS in drinking water.