The U.S. plans to limit PFAS in drinking water. What does that really mean?

The Environmental Protection Agency announced on April 10 the first-ever limits on per-and polyfluoroalkyl substances (PFAS), also known as forever chemicals, in drinking water.

The agency says that the new rule will protect 100 million Americans from six PFAS known to accumulate in the body and cause a host of health problems—including kidney and testicular cancer as well as pregnancy-induced hypertension, preterm birth, and liver and immune system problems.

“I applaud the decision,” says Susan M. Pinney, director of the Center for Environmental Genetics at University of Cincinnati. “It’s in line with what we know about the health effects of PFAS.”

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But while public health experts approve of the new rule, they contend that getting forever chemicals out of our drinking water will be a herculean task given the sheer quantity of PFAS found in it along with the difficulty in removing them. And it may come at a cost to consumers. Here’s what to know about what comes next—and what the new rule means for you.

Next steps in cleaning up the nation’s drinking water

The downside of the new rule is the cost of installing the technology to fix the problem—which estimates suggest could be between $1.5 billion to $4 billion. Under the new rule, all U.S. public water systems will have three years to test their water for the six PFAS tagged by EPA and five years to reduce levels to the new national standard of 4 parts per trillion.

The EPA estimates that between 6 and 10 percent of the nation’s 66,000 public drinking water systems may have to make changes to their infrastructure in order to abide by the new rule. Eleven states already limit PFAS levels but many will still have to make operational changes if their levels are above the national limit.

Their first task, Pinney says, should be determining the source of pollution to prevent it from entering the water system—which is cheaper and easier than removing pollution that’s already there. Many facilities will have to install granular active carbon, ion exchange, or reverse osmosis water filtration systems, proven but costly methods for filtering PFAS from water.

As for infrastructural changes, the typical facility already has processes in place to coagulate or remove solids from water, polish it to remove things like heavy metals, and a chlorination treatment to disinfect the water of harmful microorganisms. “New infrastructure will likely fall somewhere in between the polishing and chlorination phase,” says Chris Moody, who handles regulation compliance for American Water Works Association (AWWA), an organization whose membership is made up of 4,300 utility suppliers.

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Updating infrastructure may also require hiring an engineer to design any new system for filtering PFAS as well as a piloting process to test that it’s working, adds Moody.

The EPA estimates the annual cost of compliance at $1.5 billion but Moody contends it’s vastly underestimated. In a report last year, AWWA estimated the implementation budget as closer to $3.8 billion.

What will that mean for your water bill? Moody says the cost burden depends on the size of your local water treatment facility. “Small systems just don’t have the economy of scale so your cost is much higher per household,” he says.

The EPA has already announced $1 billion in federal funding through the Bipartisan Infrastructure Law, but municipalities may also have to secure funding at the state level and much of that cost is likely to be shouldered by the consumer. Moody estimates it could cost thousands annually per customer for smaller utilities and hundreds for the larger systems where the cost is spread over a greater population.

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Is it worth it?

But many experts argue that the new limits make sense given the “weight of evidence” showing health problems associated with PFAS.

“It is these very low concentrations that can have big effects overtime as chemicals bioaccumulate in the body,” says Scott Belcher, director of the Center for Environmental and Health Effects of PFAS at North Carolina State University in Raleigh.

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PFAS are ubiquitous, found in everything from cleaning products and food packaging to water-resistant fabrics. Water, says Belcher, is low-hanging fruit when it comes to cleaning up what he calls a “long-term pollution crisis.”

While the EPA has only imposed strict limits on six PFAS based on a preponderance of scientific evidence, thousands more persist in the environment. The hope is that once new infrastructure is in place it will also remove many of those chemicals that haven’t yet been banned.

In the future, Belcher says, identifying polluters ahead of time needs to be a priority. “We’ve learned lessons over the past few decades that once these compounds get into our environment, they’re extremely difficult to remove."