Enlarge / City workers unload a truck containing pallets of bottled water to distribute during a water filter distribution event on October 26, 2021 in Hamtramck, Michigan. The state Department of Health and Human Services has begun distributing water filters and bottled water to residents due to elevated levels of lead found in the drinking water due to old and un-maintained water pipes in the city. (credit: Getty | Matthew Hatcher )

The Environmental Protection Agency on Thursday proposed a stricter rule on lead in drinking water that would require that all lead service lines in the country be replaced within 10 years, and would lower the current lead action level in drinking water from 15 parts per billion to 10 parts per billion.

More than 9.2 million American households have water connections that include lead piping, according to the White House. Lead moves from the pipes into the water when the plumbing experiences corrosion, which is most severe when the water is acidic or has low mineral content. There is no safe level of lead, which is a toxic metal with wide-ranging health effects, including neurotoxic effects. In children, lead exposure can damage the brain and nervous system, slow development, lower IQ, and cause learning, behavioral, speech, and hearing problems. In adults, it can increase the risk of high blood pressure, cardiovascular problems, and kidney damage.

The EPA estimates that the rule will generate between $9.8 billion to $34.8 billion in economic benefits each year based on health improvement, including higher IQs in children, healthier newborns, lower cardiovascular risks in adults, and a reduction in care for attention-deficit/hyperactivity disorder.

Enlarge / The EPA headquarters in Washington, DC. (credit: crbellette )

On Tuesday, the Environmental Protection Agency announced that it had started the process that will see drinking water regulations place severe limits on the levels of several members of the PFAS (perfluoroalkyl and polyfluoroalkyl substances) chemical family. PFAS are widely used but have been associated with a wide range of health issues; their chemical stability has also earned them the term "forever chemicals." The agency is currently soliciting public feedback on rules that will mean that any detectable levels of two chemicals will be too much.

PFAS are a large group of chemicals that have uses in a wide range of products, including non-stick cooking pans, fire control foams, and waterproof clothing. They're primarily useful because of their water-repellant, hydrophobic nature. That nature also tends to keep them from taking part in chemical processes that might otherwise degrade them, so contamination problems tend to stick around long after any PFAS use. And that's bad, given that they seem to have a lot of negative effects on health—the EPA lists cancer risks, immune dysfunction, hormone signaling alterations, liver damage, and reproductive issues.

Back in 2021, the Biden administration announced that it was starting a research and regulatory program focused on PFAS and issued preliminary guidance on acceptable levels last year. Today's announcement is the start of a formal rulemaking process that will see the development of legally binding limits. This process involves the EPA publishing proposed rules to allow the public and interested parties a chance to provide feedback. Once that feedback is addressed, formal rules will be published.