In the next decade, the U.S. Environmental Protection Agency (EPA) aims to replace all the country’s lead pipes. Few did more to bring about the change than Ronnie Levin, who published a cost-benefit analysis in 2023 on cutting lead in drinking water, calculating the monetary costs of problems like impaired cognitive function and increased risk of health issues like hypertension and preterm birth, against the cost of mitigating the lead. The EPA had pegged the rule’s annual health benefits at $645 million, and the cost to implement it at $335 million—a benefit-to-cost ratio of 2 to 1. But Levin and her collaborator (and husband) Joel Schwartz found that mitigating lead in American water would actually save more than $8 billion a year in health benefits and at least $2 billion more in infrastructure costs, at a benefit-to-cost ratio of 35 to 1.

Levin, an instructor in Harvard T.H. Chan School of Public Health’s department of environmental health, has spent much of her career making the case for getting serious on lead mitigation and said it was “mind-boggling” the EPA agreed to such an ambitious goal. While working for the EPA in the 1980s, she composed another cost-benefit analysis of lead in drinking water, which found that a fifth of Americans were consuming levels of lead in their water that the EPA considered unsafe. The document—which scandalized the country after it was leaked to the press in 1986—was a major factor in a 1991 rule designed to minimize the amount of lead and copper in drinking water.

Levin credits the Biden Administration’s interest in lead for the speed of the change, as well as her own understanding of the EPA. Levin’s analysis strategically drew upon the EPA’s own data, assumptions, and estimates to make the case for lead mitigation, to make it harder for the government to dispute the research. While she’s thrilled about the new rule, Levin says that rulemaking isn’t good enough on its own. “Without good implementation, and without enforcement—which is what has been the case since ’91—not much is gonna happen.”