Expanded enforcement of the federal Clean Water Act would require the Washington area to weigh tougher controls on urban and suburban soil erosion and storm water pollution to protect the area's rivers and the Chesapeake Bay, environmentalists said yesterday.

"The bay doesn't care where the pollution comes from," said Michael Hirshfield, vice president of the Chesapeake Bay Foundation, who hailed the proposed crackdown by the Environmental Protection Agency. "You can't clean up the bay or any other water body without dealing with all sources of pollution."

It was difficult yesterday to assess which pollution control efforts would be given top priority in the District, Maryland and Virginia. Depending on the problem, the timetable for showing progress on waterways cleanup could range from two years to more than a decade.

"The guidelines issued by EPA tell states that to have the rivers fishable and swimmable," they will have to be concerned about everything that contributes to all excess pollution in the watershed, said Bill Matuszeski, director of the EPA's Chesapeake Bay program.

In the District, the polluted waterways are typical of what would be found in a heavily urbanized area, according to a senior EPA official. He and others cited particular problems from poorly treated sewage at certain discharge outlets.

Jim Collier, director of the District's water division, declined to cite specific areas that might be affected by the new clean water controls, saying such questions would have to be cleared with the agency's public information office.

Matuszeski said the District would need to be concerned with toxicity and nutrient overloads in the Anacostia River as well as pollution in Rock Creek and the Potomac River.

Maryland, which already has taken steps to reduce problems caused by farm runoff, has a plan for allocating pollutant reductions over the next 10 to 12 years at both point sources, such as a wastewater treatment plant, and at nonpoint sources, such as farmland or parking lots. These would include urban areas around Baltimore and the Gunpowder, Patapsco and Severn river tributaries to the Chesapeake Bay. The state already has strict sediment and erosion controls that minimize pollution associated with rapid growth and development.

In Virginia, where erosion control measures have been more lax, urban and suburban areas will need to tighten restrictions against watershed pollution, particularly runoff from yard pesticides, fertilizers and car oil. The state also will have to adopt stronger controls on watershed pollution caused by agricultural endeavors and farm animals.

Hirshfield, other environmentalists and EPA officials said the District, Virginia and Maryland would be forced to take a closer look at pollution that comes from suburban runoff and farms and not just the pollution caused by industrial plants and other point sources.

But Virginia, Maryland and Pennsylvania "should be a bit out in front of some other states in the country in responding to this new guidance from EPA," Hirshfield said, because they and other Chesapeake Bay cleanup states have been working for the past decade to improve the watershed.

"It's not like thinking about all pollution sources is anything new to the bay region," he said.

For now, Matuszeski said, steps to clean up the bay are being taken on a voluntary basis--with the goal of keeping nutrients from damaging the bay by 2010. This is being done, he said, "with the understanding that if [it doesn't work] there will have to be formal regulatory allocations" of pollutant reductions.

"The [EPA] guidance for the Chesapeake provides for cooperative arrangements in advance of doing full-blown regulatory approaches," he said.