The Clinton administration is proposing a new regulation that would require states to write individual clean-up plans for every body of water that is too dirty for fishing and swimming, currently about 20,000 rivers, bays, and lakes, or 40 percent of water bodies in the U.S. The proposed regulation from the EPA, which would enforce a largely ignored part of the federal Clean Water Act, is a new tack on battling water pollution: Instead of focusing on specific quantities of discharges from individual polluters, the regulation would consider the overall quality of a body of water, taking into account its ability to handle all of its different sources of pollution.