In 2021, the American Society of Civil Engineers gave U.S. drinking water infrastructure a C- on its report card. Why? The system that takes water from lakes, rivers, aquifers, and other sources to a treatment plant and eventually into your home is failing. That, along with upstream pollution, may pose a risk to your health. Here’s what to know about what’s in your water...and what you can do about it.

Erik Olson head shot

Erik Olson is a senior strategic director at the Natural Resources Defense Council (NRDC), a nonprofit environmental advocacy group. Olson’s work has helped revamp laws that protect America’s drinking water from contaminants. He spoke to Nutrition Action’s Caitlin Dow.

Your health at risk

Q: How can drinking water threaten our health?

A: We worry about two categories. The first is acute concerns—things that happen shortly after you’re exposed.

Microbial contaminants like Giardia, Cryptosporidium, or Legionella are microbes that live in the water and can make you sick fairly quickly after you drink water that wasn’t adequately treated.

Q: Can chemical contaminants also have acute effects?

A: Yes. Nitrates are one example. They’re most common in rural areas and can cause what’s called blue baby syndrome. If a baby is fed formula that’s reconstituted with tap water that’s high in nitrates, the baby may not get sufficient oxygen.

Q: Is the second category chronic problems?

A: Yes. And they’re much more widespread and concerning. For example, lead causes irreversible damage to children’s developing brains, and it’s linked to high blood pressure and cardiovascular disease in adults.

We also worry about cancer linked to contaminants like arsenic or PFAS—per- and polyfluoroalkyl substances. And you would not want chemicals like vinyl chloride, which was spilled in the February train wreck in Ohio, in your drinking water because it may increase the risk of cancer or liver damage.

Who’s in charge?

Q: Who is in charge of making sure that our tap water is safe?

A: In 1974, Congress passed the Safe Drinking Water Act, which required the Environmental Protection Agency to develop drinking water standards that are enforced primarily by the states. And if the states fail to do that, the Act says that the EPA is supposed to step in to make sure that drinking water is protected.

Q: Has the law been successful?

A: There have been some successes and some failures. There are now about 100 contaminants like toxic chemicals, metals, and microbes that are regulated in drinking water, which is good.

But there are literally thousands of contaminants that are not regulated. The EPA recently proposed rules to regulate six different PFAS. That’s the first time the agency has proposed limits on any new drinking water contaminants on its own initiative since 1996. So we’re sort of stuck in neutral with the EPA.

Q: Can people assume that their water doesn’t exceed the EPA’s limits?

A: No. Often the states and the EPA don’t enforce the law effectively. Our reports have shown that tens of millions of Americans are drinking water from systems that are violating the drinking water standards. For example, in 2015, we found more than 12,000 health-based violations in public water systems serving more than 27 million people.

Q: Why are there so many violations?

A: In many cases, the root cause is a severe underinvestment in our drinking water infrastructure and a failure to control the sources of pollution in the first place.

Many of our water systems were built over 100 years ago and have not been adequately updated. We’ve basically been living off the investments that our parents and grandparents and great-grandparents made.

construction workers digging and working on pipes under concrete.
The Natural Resources Defense Council estimates that the aging U.S. water infrastructure needs nearly a trillion dollars in upgrades.
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An uneven playing field

Q: Are all communities equally harmed by water contamination?

A: No. Certain communities are disproportionately affected by contaminated water and poor enforcement of the standards. That includes communities with more households of lower socioeconomic status or more Black, Indigenous, and Latino people.

Q: Why?

A: It’s often a double whammy. Underinvestment is a serious contributor to the problem. And those same communities tend to be dumping grounds for contaminants from nearby industries that discharge toxic chemicals or nearby farms or ranches that pollute the water with pesticides, fertilizer, or animal waste.

Q: Are smaller water systems at greater risk?

A: We do see higher rates of violations in water systems that serve fewer than 3,300 people, often because they can’t afford high-quality water treatment. They often can’t even afford full-time staff. But some large systems have similar problems.

Q: Why?

A: Many cities have lost significant population in the last 50 years or so. Flint, Michigan, Newark, New Jersey, and Jackson, Mississippi are good examples.

That means a smaller number of people, often low-income, have to support a system that was designed for way more people.

It’s like living in a house that’s falling apart and you only have a couple of people paying for upkeep, when previously a lot of folks were paying into the house.

And those communities often don’t have the political clout to get action. We saw that in Jackson, Mississippi, recently. They’ve had frequent boil-water alerts and broken water mains all over the city. It’s a majority Black city that was not getting adequate funding from the state.

What to do

Q: How can consumers find out what’s in their water?

A: Each public water system is required to provide an annual report, often called the Consumer Confidence Report. Small systems generally mail them to people and larger systems will post them online.

That report is required to disclose the level of all detected contaminants that EPA regulates and any violations that occurred over the past year.

Q: Are the reports reliable?

A: Sometimes. But utilities play all sorts of games with them. Some systems include big front pages signed by the mayor or by the water utility director saying, “We have some of the safest water in the country.”

And then you have to flip through several pages to find a table that’s mostly unintelligible to any ordinary human that lists all the contaminants that were tested and any violations found.

Utilities also often imply or outright state that if a system is in compliance, the water is totally safe. But it’s not necessarily safe, because the drinking water standards are often very weak. Your water may have plenty of contaminants that are not safe but are unregulated, so the water company doesn’t test for them.

Q: What else do the reports leave out?

A: Most contaminants are tested at the water treatment plant. So if the water picks up contaminants between the treatment plant and your house, you wouldn’t know.

Only a handful of contaminants like copper, bacteria, disinfection byproducts, and lead are required to be tested at the tap.

Water companies have to test a certain number of homes at high risk of having lead pipes. But unless your home is tested, you won’t know if there’s lead coming out of your tap.

And if your water comes from a well, you have to get it tested yourself.

Q: How else can you find out what’s in your water?

A: If you’re willing and able to spend the money, you can pay to have your water tested. We recommend only using a state-certified lab.

There are some online sites like, which partners with state-certified labs, where you can order a test for a couple of contaminants for around $50, or for a huge suite of contaminants for around $150 to $700. You can test for PFAS, lead, arsenic, bacteria, all sorts of things.

Q: What is the long-term solution for making drinking water safer?

A: Congress, states, and water systems must invest in fixing our outdated infrastructure. Also, we have to fix the Safe Drinking Water Act and the way the EPA sets standards so that emerging contaminants are controlled and polluters pay for cleaning up our water.

More on contaminants in water

Per- and polyfluoroalkyl substances (PFAS)

What are they?
water pipe releasing water into larger body of water
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“PFAS are a class of man-made chemicals,” explains Jamie DeWitt, professor of pharmacology and toxicology at East Carolina University. “They are used to make coatings that have nonstick and stain-, grease-, and water-repellent properties.”

You’ll find them in nonstick pans, waterproof clothing, carpets, cosmetics, food packaging, dental floss, and more.

“Depending on how they’re defined,” says DeWitt, “there are roughly 5,000 to 10,000 individual PFAS.”

PFAS are often called “forever chemicals” because they may take thousands of years to break down.

How can they harm you?

“Of the handful of PFAS that have been studied, we’ve seen links between exposure to several of them and kidney and testicular cancer, increased cholesterol, reduced response to vaccines, and high blood pressure during pregnancy,” says DeWitt.

How do they get into drinking water?

“PFAS can be emitted directly into water when they’re manufactured,” notes DeWitt. Concentrations are likely to be highest in water from areas where industries discharge PFAS into nearby waterways.

But even if you don’t live near one of those plants, your water may still be contaminated.

“PFAS have been detected in the vast majority of water supplies that have been tested,” says DeWitt. “But not all water supplies have been tested.”

Roughly 180 to 270 million U.S. residents likely receive water contaminated with PFAS, one study estimated.

How do you know if they’re in your water?

The EPA doesn’t currently require water utilities to measure and report PFAS (though some do). In March, the agency proposed new, enforceable limits for six PFAS, but it could take years before you see those or other PFAS listed in your annual water report.

While that’s long overdue, DeWitt and others argue that PFAS should be managed as a class, not individually.

“There are thousands of these chemicals, and it will take lifetimes for us to evaluate them all,” she says.

“Or we can just lump them all together because many of the ones that have been studied harm our health and the environment.”

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What is it?

A metal used, among other things, to make pipes.

How can it harm you?
outside of a rusted looking pipe
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No amount of lead is safe. Children are at greatest risk because their brains are still developing and they absorb lead more efficiently than adults. That can damage the brain and nervous system, leading to slower growth and development and learning and behavioral problems. During pregnancy, even relatively low blood levels of lead can lead to miscarriage or low birth weight. And in anyone, lead exposure can lead to high blood pressure, cardiovascular disease, and impaired kidney function.

How does it get into drinking water?

Lead isn’t naturally found in most lakes, rivers, or groundwater. In 1986, Congress banned the use of lead in new service lines (which connect your home’s plumbing to the water main). But about 9 million lead service lines are still in use in the U.S., estimates the EPA.

Lead can make its way from pipes to drinking water in one of two ways: If the water is corrosive and the water or pipes are not adequately treated to control corrosion, lead can leach into the water, explains the NRDC’s Erik Olson. “But even if your water isn’t particularly corrosive, lead pipes are a ticking time bomb,” he adds. “Basic things like maintenance on the water main can shake loose little particles of lead into your water.”

How do you know if it’s in your water?

You can test at the tap, but lead levels can vary significantly from day to day. So one test may not mean you’re in the clear.

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The toxic element seeps into water from rock and soil (where it occurs naturally) or from human-caused contamination like old industrial or hazardous waste sites with high levels of arsenic. Long-term high-dose exposure to arsenic causes skin cancer and lesions, is linked to nerve damage, and may raise the risk of liver, bladder, and lung cancer.

No amount of arsenic is safe, so you want to see 0 parts per billion (or “not detected”) on your water report, though the report will only flag arsenic as a violation if it’s over 10 ppb.

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Disinfection byproducts

gloved hand holding a beaker filled with water
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At the treatment plant, water is disinfected with chemicals like chlorine and monochloramine to kill microbes like E. coli and Giardia. But the disinfectants can react with naturally occurring substances in the water to form byproducts that are linked to bladder cancer and possibly birth defects or other reproductive problems.

According to the Natural Resources Defense Council, disinfection byproducts were the most common violations of Safe Drinking Water Act rules in 2015, affecting the water supply of roughly 12.6 million Americans. Look for “total trihalo­methanes” (which shouldn’t exceed 80 parts per billion) and “haloacetic acids” (which shouldn’t exceed 60 ppb) in your annual water report.

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water dripping from filter

Testing the Waters

How to pick a water filter

Worried about your tap water...and thinking of switching to bottled? There’s no guarantee that it’s safer. And bottled water comes with a cost to you and the environment. A home filter makes more sense, but finding the right one takes some research.

Get our tips