Today, the Environmental Protection Agency announced that it has finalized rules for handling water supplies that are contaminated by a large family of chemicals collectively termed PFAS (perfluoroalkyl and polyfluoroalkyl substances). Commonly called "forever chemicals," these contaminants have been linked to a huge range of health issues, including cancers, heart disease, immune dysfunction, and developmental disorders.

The final rules keep one striking aspect of the initial proposal intact: a goal of completely eliminating exposure to two members of the PFAS family. The new rules require all drinking water suppliers to monitor for the chemicals' presence, and the EPA estimates that as many as 10 percent of them may need to take action to remove them. While that will be costly, the health benefits are expected to exceed those costs.

Going low

PFAS are a collection of hydrocarbons where some of the hydrogen atoms have been swapped out for fluorine. This swap retains the water-repellant behavior of hydrocarbons while making the molecules highly resistant to breaking down through natural processes—hence the forever chemicals moniker. They're widely used in water-resistant clothing and non-stick cooking equipment and have found uses in firefighting foam. Their widespread use and disposal has allowed them to get into water supplies in many locations.

They've also been linked to an enormous range of health issues. The EPA expects that its new rules will have the following effects: fewer cancers, lower incidence of heart attacks and strokes, reduced birth complications, and a drop in other developmental, cardiovascular, liver, immune, endocrine, metabolic, reproductive, musculoskeletal, and carcinogenic effects. These are not chemicals you want to be drinking.

The striking thing was how far the EPA was willing to go to get them out of drinking water. For two chemicals, Perfluorooctanoic acid (PFOA) and Perfluorooctanesulfonic acid (PFOS), the Agency's ideal contamination level is zero. Meaning no exposure to these chemicals whatsoever. Since current testing equipment is limited to a sensitivity of four parts per trillion, the new rules settle for using that as the standard. Other family members see limits of 10 parts per trillion, and an additional limit sets a cap on how much total exposure is acceptable when a mixture of PFAS is present.

Overall, the EPA estimates that there are roughly 66,000 drinking water suppliers that will be subject to these new rules. They'll be given three years to get monitoring and testing programs set up and provided access to funds from the Bipartisan Infrastructure Law to help offset the costs. All told, over $20 billion will be made available for the testing and improvements to equipment needed for compliance.

The Agency expects that somewhere between 4,000 and 6,500 of those systems will require some form of decontamination. While those represent a relatively small fraction of the total drinking water suppliers, it's estimated that nearly a third of the US' population will see its exposure to PFAS drop. Several technologies, including reverse osmosis and exposure to activated carbon, are capable of pulling PFAS from water, and the EPA is leaving it up to each supplier to choose a preferred method.

Cost/benefit

All of that monitoring and decontamination will not come cheap. The EPA estimates that the annual costs will be in the neighborhood of $150 billion, which will likely be passed on to consumers via their water suppliers. Those same consumers, however, are expected to see health benefits that outweigh these costs. EPA estimates place the impact of just three of the health improvements (cancer, cardiovascular, and birth complications) at $150 billion annually. Adding all the benefits of the rest of the health improvements should greatly exceed the costs.

The problem, of course, is that people will immediately recognize the increased cost of their water bills, while the savings of medical problems that don't happen are much more abstract.

Overall, the final plan is largely unchanged from the EPA's original proposal. The biggest differences are that the Agency is giving water suppliers more time to comply, somewhat more specific exposure allowances, and the ability of suppliers with minimal contamination to go longer in between submitting test results.

"People will live longer, healthier lives because of this action, and the benefits justify the costs," the agency concluded in announcing the new rules.