Stoner has been working in environmental policy for more than 25 years. As the agency's top official focused on water, she oversees programs ensuring that drinking water is safe; she also heads up programs aimed at restoring and maintaining oceans and watersheds. Stoner started her career in environmental policy and law in 1987 as a trial attorney in the Justice Department's Environment and Natural Resources Division. She came to EPA as director of the Office of Policy Analysis in the Office of Enforcement and Compliance Assurance, where she contributed to EPA's environmental auditing and self-disclosure policies. Most recently, Stoner worked at the environmental advocacy group Natural Resources Defense Council, where she was the codirector of the group's water program. Stoner spearheaded the group's efforts to clean up the Anacostia River in Washington, low-impact development measures that reduce stormwater flows and sewer overflows into the river. Stoner, who grew up in Virginia, is a 1982 graduate of the University of Virginia and a 1986 graduate of Yale Law School.