Causes and Effects of Lead in Water

How this harmful neurotoxin got into our taps and what it’ll take to get it out.

Marcelina Pedraza at her home in the East Side neighborhood of Chicago on June 3, 2021. Pedraza had her water tested for lead in January 2020, and lead was present in three samples.

Taylor Glascock for NRDC

Tough yet malleable and easy to bend and work with, lead became the chosen metal for water pipes long, long ago—a use, in fact, that dates back to the ancient Romans. Today we know that this material doesn’t belong in our homes—and certainly not in our drinking water systems. Lead is notoriously dangerous, with medical and public health experts agreeing that there is no safe level of lead in the human body. Additionally, this potent, irreversible neurotoxin is especially harmful to babies and young children.

In 2016, Flint, Michigan, made headlines around the world as it was revealed that blood-lead levels in children (in areas where lead in water had increased) had nearly doubled since the city started pumping in drinking water from a new source without properly treating it—a hasty, cost-saving move. The inadequate treatment and testing of the water resulted in a series of major water quality and health issues for Flint residents. These issues were chronically ignored, overlooked, and discounted by government officials even as complaints of foul-smelling, discolored, and off-tasting water mounted for 18 months.

The Flint water crisis represented government failure at the city, state, and federal levels. Driven by the determined, relentless efforts of the Flint community to bring the injustice to light, it also forced a national reckoning with the vulnerability of the nation’s aging water infrastructure.

Between 1900 and 1950, a majority of America’s largest cities installed lead water pipes. Some cities even mandated them, often in response to an industry campaign to enact rules requiring lead pipes. And because these pipes can last 75 to 100 years or more, their legacy lives on today. In 2024, the U.S. Environmental Protection Agency (EPA) estimated that there are currently about 9 million lead service lines across the United States.

An advertisement placed by the National Lead Company in National Geographic magazine in 1923 touted the safety of having lead pipes in homes.

Photo courtesy U.S. National Library of Medicine

Since the revelations in Flint, dozens of cities have been found to have dangerously elevated levels of lead in homes, schools, and daycare centers. High lead levels have been found in tap water in Baltimore, Buffalo, Benton Harbor, Chicago, Milwaukee, Newark, New York, Pittsburgh, Syracuse, and Washington, D.C. One NRDC analysis found that between 2018 and 2020, 56 percent of the U.S. population drank from water systems with detectable levels of lead.

The issue is widespread. A new map by NRDC shows that lead pipes occur in every U.S. state, and that many states and utilities do not know what the majority of their pipes are made of. This means their inventories may grossly underestimate the number of lead lines. However, the map and its underlying 2024 EPA data give us a more comprehensive view of the extent of the problem. They are also integral to delivering action: The data displayed is being used to allocate billions of dollars in federal funds to states, based on how many lead pipes they have reported.

So how does the lead get into our tap water? The simplest explanation is that when plumbing pipes and fixtures containing lead corrode, the lead can dissolve or flake into the water that flows from our faucets. You can’t see, smell, or taste lead, so even water that runs clear can contain it.

Corrosion is a chemical reaction that happens between the water and the lead-containing pipe or plumbing fixture. Certain qualities of the water—for example, acidity and varieties of dissolved materials in the water—can play a major role in that reaction. Other factors include water temperature, age and wear of the plumbing fixtures, and the length of time water sits stagnant in the pipes.

Common sources of lead plumbing include:

The EPA requires water utilities to conduct water-quality monitoring, to use corrosion-control treatments, and to monitor and treat source water as needed to provide safe drinking water. While Flint is the most infamous example, dozens of other cities are failing to properly treat their water. For example, in 2001, Washington, D.C., changed its disinfectant from free chlorine to chloramines without first studying the potential impact. The chloramines made the water far more corrosive, and tragically, extremely high lead levels pervaded the city. (D.C. initially failed to disclose the issue and is still working to replace its lead pipes today.)

Anti-corrosion chemicals can be used to reduce the release of lead and other metals from the pipes into the water. Corrosion inhibitors like zinc orthophosphate are used by water systems to coat the inside of lead pipes and fixtures with a thin, protective layer that reduces leaching and flaking.

Even the ancient Romans understood lead can make you sick. Today, health experts—including scientists at the Centers for Disease Control and Prevention and the American Academy of Pediatrics—agree that there is no safe level of lead exposure. While it’s toxic to everyone, fetuses, infants, and young children are at the greatest risk for lead poisoning because their brains and bodies are rapidly developing and more easily absorb lead than do those of older children and adults. But adults are also at risk, particularly from cardiovascular disease due to lead exposure. As levels increase, these harms become more severe.

To the cells in our bodies, lead looks a lot like the mineral calcium, which is vital to healthy brain development and function, strong bones and teeth, and a healthy cardiovascular system. As a result, lead that has been absorbed or ingested can travel through our bodies and cause problems in our bones, teeth, blood, liver, kidneys, and brain, disrupting normal biological function.

High levels of lead exposure can be serious and life threatening. In children, symptoms of severe lead poisoning include irritability, weight loss, abdominal pain, fatigue, vomiting, and seizures. Adults with lead poisoning can experience high blood pressure, cardiovascular disease, joint and muscle pain, difficulty with memory or concentration, and harm to reproductive health.

Jeremiah Loren, 12, rinses with bottled water after brushing his teeth at home in Flint, Michigan, on January 20, 2016.

Brittany Greeson/The New York Times/redux

Even moderate to low levels of lead exposure—which might cause subtle symptoms—can still produce serious harm. Health effects include hearing loss, anemia, hypertension, kidney impairment, immune system dysfunction, and toxicity to the reproductive organs. Low levels of exposure can interfere with thought processes and lower children’s IQ and also cause attention and behavioral problems—all of which affect lifetime learning. Children with serious lead-related neurological impacts are less likely to graduate from high school and are more prone to delinquency, teen pregnancy, violent crime, and incarceration.

Researchers with NRDC, Environmental Justice Health Alliance, and Coming Clean have analyzed EPA data and reported a correlation between a community’s racial composition, bad water, and inadequate response to violations. What’s more, wealthier white communities, who can afford to pay for pipe removal, are more likely to benefit from lead pipe removal programs than are low-income communities of color. This is particularly true for those programs that charge individual property owners for replacement.

In a demonstration outside the Prudential Center in Newark, New Jersey, protesters bring attention to the city’s water crisis.

Karla Ann Cote/NurPhoto/Getty Images

The risk of drinking lead-contaminated water also compounds other health risks disproportionately faced by marginalized communities. For example, as NRDC’s Chakena D. Perry explained in a 2023 article in Harvard Public Health magazine, lead exposure before and during pregnancy can cause fertility problems, premature birth, and miscarriage. This is especially dangerous for Black women, who are already three times more likely to die from pregnancy-related complications than white women.

Lack of access to clean water is a major environmental justice issue—and its persistence proves that we need to actively address these barriers.

Unprecedented federal funding for lead pipe removal is now helping to tackle this massive problem. For example, the 2021 Bipartisan Infrastructure Law (also known as the Infrastructure Investment and Jobs Act) includes a $15 billion commitment to replace lead pipes that connect homes to drinking water mains. It also makes available an additional $11.7 billion that can be used by communities for any drinking water infrastructure priority, including removal of lead service lines if a state decides to spend the funds on that. NRDC fought alongside community partners and others to secure the funding, and we are now working with these groups to ensure the money is fairly and equitably distributed—and flowing to the communities most in need.

Workers with the East Bay Municipal Utility District replace a water pipe in Walnut Creek, California.

Justin Sullivan/Getty Images

The EPA’s Lead and Copper Rule Improvements (LCRI), which took effect on October 8, 2024, sets the stage for how the entire nation will address lead in drinking water for years to come. This new regulation was announced nearly three years after NRDC, along with partner groups and 10 state attorneys general, challenged the EPA in court for its failure to meaningfully address the issue. The new rule mandates replacement of nearly every lead service line in the United States, in most cases within 10 years.

However, the regulation does leave some gaps. Advocates are particularly concerned that it gives an extension to the water systems serving some disproportionately affected communities. For example, Chicago—the city with the most lead service lines in the nation—will have an additional decade to do this work. It also allows utilities to skirt their duty to fund lead service line replacements, authorizing them to ask individual property owners to pay for some or all of the work. This can exacerbate environmental injustice by overburdening low-income homeowners and renters who cannot afford the cost of replacing their lead service line. The rule also does not fix the problem of lead contamination in schools and childcare centers, which often have significant lead contamination, often due to lead-containing indoor plumbing.

NRDC is continuing to call on the EPA, Congress, and state and local officials to address these injustices and gaps; to strengthen enforcement and reporting; and to avoid putting any additional financial burden on low-income homeowners or renters, whose landlords are unlikely to pay the cost of lead pipe replacement. Additionally, strong measures are needed to protect schoolchildren and kids in daycare facilities.​​

Local decision makers—including state and city officials, as well as utilities—must also help speed up the transition away from lead pipes. Some states have already made significant headway in this work by working together with communities. For example, in the wake of the Flint water crisis, NRDC, our community partners in Flint, and many other groups pushed the state of Michigan to adopt the nation’s strongest LCR—paving the way to full replacement of lead services lines paid for by local water utilities and establishing other precautions to reduce exposure. Other states, like Illinois, New Jersey, and Rhode Island are following suit. To prevent future disasters like the one in Flint, the EPA should mandate even stricter protections. Requirements should include an at-the-tap standard and filtering, treating, testing, and improving public education around the issue.

The first thing you should do is learn more about your water. The EPA requires all community water systems to prepare a Consumer Confidence Report (often called an annual drinking water quality report or right-to-know report) for customers. This report tells you where your water comes from and what’s in it. And if it’s not available on the EPA website, call or check the website for your water utility. But beware: These water utility-generated reports often are hard to read, and some may hide, omit, or even mislead you on some key facts. So read and consider them with caution.

To find out if you have lead pipes, check out NRDC’s step-by-step guide to see if you have a lead service line. You can ask your water utility if your local community has public records about drinking water service lines. All water systems were supposed to do an initial inventory of their lead service lines by October 16, 2024, though utilities often say that many of their pipes are made of “unknown material.” Your water supplier may also have a map identifying local lead pipes or other information about your home or area. Or ask a licensed plumber to determine if your plumbing fixtures or the pipe that connects your home to the water main are made from lead.

If your water comes from a well or other private supply, you can have it tested by a state-certified lab to check for lead, bacteria, nitrates, arsenic, and other contaminants (see details below). Also consider checking with your local health department or with a local water utility that uses groundwater to learn more about any contaminants of concern in your area.

Some states and cities offer free water testing for lead, so you should check with your local health department or water utility. You can also use an independent testing laboratory, such as Healthy Babies Bright Futures, which offers below-cost lead testing kits to community groups. The EPA website is also a resource to find a list of certified labs that can perform the testing for a fee. (Labs listed here will charge about $50 for a single lead test. Testing for other common contaminants like bacteria, nitrates, and arsenic will cost more.)

Be sure to collect multiple samples of lead in your tap water and avoid turning on the water in your home for at least six hours prior to sampling. There may be varying instructions from your city or lab on how to collect the samples, but collecting this “pre-flush” sample is a must. This EPA guide offers more information about home water testing.

There are a number of ways to reduce your exposure and remove lead in your tap water.

Several common home water-treatment products can also reduce lead—those listed below can be purchased at hardware stores and online:

Regardless of the method you choose, certification that the filter meets NSF or WQA standards for lead removal, as well as proper maintenance and upkeep, like replacing filters, are critical.

Finally, you can have your lead pipes removed. If it’s the pipe that runs from the water main to your home that contains lead, often the utility will take the position that it’s the responsibility of both the utility and the homeowner. Homeowners can contact their water system to learn about how to remove the lead service line. That said, here’s an important caveat: If you find that the service line contains lead, do not remove that pipe yourself. The city or an experienced and approved contractor should remove and replace the entire length of the lead service line, because replacing only part of it could cause lead levels to increase.

Even after your lead service line is replaced, your water should be filtered for at least six months, since lead particles can adhere to your indoor plumbing for several months and can be released into your tap water. In addition, if you have indoor lead pipes, lead solder, or faucets that contain lead, consider replacing them. In the meantime, until you can make the upgrade, it’s critical to filter your tap water before drinking or cooking with it.

This story was originally published on September 1, 2023, and has been updated with new information and links.

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