Clean water is a critical resource not only for drinking but also for agriculture, energy production and high-tech manufacturing. But severe drought -- once seen as an issue only for the arid West -- has become a fact of life in many parts of the United States. Meanwhile, many cities depend on water mains and sewer pipes more than 100 years old. Environmental laws have sharply cut water pollution and improved drinking-water quality since the 1970s. But experts say the nation needs to spend more than $250 billion in the next several years to modernize water treatment systems, and current investments are falling short. The Environmental Protection Agency has proposed new ways to regulate water pollutants, and economists say charging more for water would promote conservation. But whether Americans will pay more for a resource that many view as a basic human right remains to be seen.

Jennifer Weeks is a freelance writer in Watertown, Mass., who specializes in energy and environmental issues. She has written for The Washington Post, The Boston Globe Magazine, Environment, On Earth and other publications, and spent 15 years as a congressional staffer, lobbyist and public policy analyst. She holds a B.A. from Williams College and master's degrees from the University of North Carolina and Harvard University.