This story appears in the March 2019 issue of National Geographic magazine.

When my young daughter says she’s thirsty, I take for granted that the water from our kitchen tap is clean and safe. In fact, that’s what most Americans assume. But should we?

As we mark World Water Day on March 22, the disturbing truth is that roughly a quarter of Americans drink from water systems that violate the Safe Drinking Water Act. Violations range from failing to properly test water to allowing dangerous levels of lead or arsenic—and occur everywhere: in rural communities and big cities, in red states and blue ones.

The lead contamination crisis in Flint, Michigan, was extreme—and shocking because of the role that race played. However, it was not an isolated case, and we need to consider it a national wake-up call.

Across the country, water systems are old, badly maintained, and in dire need of modernizing—from lead service lines in Milwaukee, Wisconsin, and Newark, New Jersey, to silt and debris in drinking water after heavy rain in Austin, Texas, to fecal contamination in Penn Township, Pennsylvania. Worse, some are managed by dysfunctional agencies where incompetence and socioeconomic and racial bias may determine whether a community is made sick by its drinking water. The reality is that we can no longer assume that our water is safe to drink.

How unsafe is it? Depending on the source of contamination and the exposure, health effects include neurological problems and developmental disabilities in children (lead), interference with hormones (perchlorates), and increased risk of cancers of the skin, bladder, and kidney (arsenic). The Environmental Protection Agency regulates more than 90 contaminants—but a hundred more that are tracked are so far unregulated.

Everyone has a right to clean water, no matter what you look like, how much money you make, or which political party you favor. In America, that right is enshrined in the Clean Water Act of 1972, which defines how the EPA regulates pollutants in U.S. waters, and the Safe Drinking Water Act of 1974, which establishes maximum amounts of pollutants in all public water systems. Those federal laws were passed at the peak of environmental degradation in our country—a time when smog choked our cities and rivers were so contaminated they regularly caught fire.

Those laws and many other regulations at state and city levels have made great progress toward reducing pollution and addressing public health. Some of us now don’t worry about the toxicity of the air for our children’s afternoon soccer games or the flammability of the local river, primarily because our environmental protections have worked. But in far too many places around the country, those basic laws are not being upheld or enforced, and people are suffering the consequences.

Look at Puerto Rico. The water situation there was unacceptable—the worst in the nation—even before Hurricane Maria in 2017. An analysis by my organization, the Natural Resources Defense Council (NRDC), showed that almost all of Puerto Rico’s residents in 2015 got their water from systems that violated the Safe Drinking Water Act and nearly 70 percent of them got their tap water from sources contaminated with coliform bacteria, disinfection by-products, and more.

Maria created a full-blown humanitarian crisis. People had no choice but to get their drinking water from toxic sources, and scores ended up in emergency rooms with gastrointestinal illnesses. Even now, more than a year after the storm, Puerto Ricans are still warned to boil water before drinking it.

As climate change increases the intensity and duration of hurricane season, Puerto Rico will likely find itself in even more dire circumstances. That means we need to invest significant resources now in the island’s water and power infrastructure, which remains fragile at best.

So far, U.S. leaders have approved only a small fraction of what Puerto Rico needs to protect itself. By shortchanging this American island, we are condemning it to more climate-related destruction and an ongoing water crisis. And many other vulnerable communities are in the same fix.

Across America, the first step in securing clean drinking water is better information. In 2016, New York became the first state in the country to require school districts to test drinking water sources for lead, something the Safe Drinking Water Act fails to do.

NRDC looked at the data on drinking water from New York State’s public schools. Our analysis showed that 82 percent of public schools in New York had one or more taps that exceeded the state’s lead action level—and as you might expect, the problem was worse in lower-income schools.

New York already is one of 10 states (along with the District of Columbia) that require universal blood tests for lead before age three. Now, newly armed with data on lead sources, the state has an opportunity to protect the 2.7 million children in public schools (including my daughter) and to become an example for other states.

Lead makes headlines, but it’s not the half of it. The more we look for pollution, the more we’ll find, and the list of contaminants is long: Coliform bacteria near dairy farms in Wisconsin. Nitrates from fertilizers in Iowa’s rivers. Lead, mercury, and uranium in fracking fluid in places like Ohio, Oklahoma, Pennsylvania, and North Dakota. Toxic chemicals such as those in Teflon that are so ubiquitous they’re found in the blood of 98 percent of people in the United States and nearly every country in the world. (For more on this topic, visit thedevilweknow.com.)

The problem may feel overwhelming, but together we can solve it. We need to start with the basics, like replacing lead pipes and fixing deteriorating mains. Then we can modernize our aging water infrastructure with more filtration or treatment processes to better purify wastewater before it enters the drinking water system. We need to better regulate pollutants, strengthen protections for drinking water, and improve testing. A bonus: We can do all of these things and create good-paying new jobs in communities throughout the country.

It all begins by insisting that clean water not be treated as a partisan issue. No matter how you voted in the past two elections, you didn’t vote for contaminated drinking water. So, together we need to hold government officials to account at all levels. We can start with leaders in Washington who, in my estimation, are trying to shrink government’s role in protecting public health.

In 1970 millions of Americans rose up and demanded stronger environmental and public health protections—and won them. Nearly 50 years later we need to rise up again.

This is where you come in. You can join the many people taking to the streets to march for a clean environment. You can read up on water issues in your community, then attend town hall or water department hearings. You can call your representatives and tell them that water quality matters to you and your family. Your voice is exactly what’s required now to defend and make real our right to clean water.