Recent flooding in the Midwest has brought to the surface another crisis involving the nation's aging infrastructure: Heavy rains regularly overwhelm sewer systems, causing lake and river pollution.
Overtaxed sewer systems send 860 billion gallons of raw or partially treated sewage each year into the nation's waterways, according to the Environmental Protection Agency. The problem of aging sewers is growing worse as federal funding for repairs has fallen, according to the American Society of Civil Engineers.
The society gave the nation's wastewater treatment plants a grade of D-minus in its latest Report Card for American's Infrastructure. That 2005 grade was down from a D in the previous report in 2001.
A draft EPA report says cities should prepare for overflows to worsen, as climate change may lead to more rain and snow in the Great Lakes area and the Northeast.
The environmental group American Rivers estimates the nation's sewage systems need $390 billion worth of work over the next 20 years. Local officials, however, say residents balk at the cost.
The EPA says combined sewer systems, which carry both waste and storm runoff, serve about 770 communities containing about 40 million people, mostly in the Northeast, the Great Lakes area and the Pacific Northwest. The EPA is pushing cities to replace their combined systems with separate lines.
"It's a difficult issue to address because of the amounts of money and the time needed to fix that many miles of sewer," said Kevin Weiss of the EPA's Office of Wastewater Management.
Critics say the federal government has shirked its responsibility to help cities with such costs. Bills under consideration in Congress would increase funding. Without federal and state help, cities face an unacceptable choice, said Josh Klein, organizer of the Act for Healthy Rivers project for American Rivers.
"Of course no one wants sewage in their basements, but no one wants sewage in their rivers, either," he said.