Like most people, Dan Onorato never thought much about sewers before winning the county's chief executive job. Now he said he no longer has that luxury.

Finding a cooperative fix to the multibillion-dollar sewer problems in Allegheny County has become a "big priority," Mr. Onorato said, and holds the key to future economic development in the region.

Speaking yesterday at the eighth annual 3 Rivers Wet Weather Sewer Conference in Cranberry, he urged 250 municipal leaders, managers and public works professionals to work together to comply with federal orders and end sewage overflows into area rivers and streams every time it rains.

"I know more about sewers than I ever thought I would," Mr. Onorato said. "And I know if our sewer systems aren't fixed that could stop all economic development."

He said the county has installed water and sewer lines to facilitate warehouse development near Pittsburgh International Airport and invested $1.1 billion for cleanup and infrastructure development at old steel mill sites, but the sites will be unusable without functioning sewer systems.

"There are 900 acres of old mill sites, riverfront acres, that people would love to be on," Mr. Onorato said. "So it's collectively important for the region to get this done."

There are 414 combined sewer overflows in Allegheny County. The 279 of those in the Allegheny County Sanitary Authority service area allow an estimated 16 billion gallons of untreated sewage and storm water to flow into the region's rivers each year. There are also 50 sanitary sewer overflows in the Alcosan system.

In 1997, the EPA threatened to fine Alcosan and its member municipalities $275 million if they continued to discharge sewage into the rivers. If the sewage problems aren't fixed, the government could also limit or prohibit sewer hookups for new development.

Eliminating sanitary sewer overflows and limiting the combined sewer overflows to a half-dozen or fewer annually will cost Alcosan an estimated $1 billion, and its member municipalities and the city another $2 billion. Mandated sewer improvements in 10 other Western Pennsylvania counties could cost another $7 billion.

Two and a half years ago the U.S. Environmental Protection Agency ordered Alcosan's 82 municipalities and the city of Pittsburgh to map and assess their municipal-owned sewer systems, monitor flows and devise a plan to fix problems.

Some of that work has been done, but Mr. Onorato said some of the county's 130 municipalities will need help. He offered to have the county lead an umbrella group to ride herd on the effort.

"This is not a power grab. In fact, it's the last thing I want to do, because the voters won't see the sewer improvements underground. They'll just see their bills go up," Mr. Onorato said.

"But we have 25 municipalities that are fiscally distressed and can barely afford a policeman or a dump truck for public works. We have to take those who are falling back into account because if we don't have good mapping and assessment of sewer conditions it will hold us back on the fix."

Mr. Onorato said the county would also seek funding help by lobbying state and federal leaders, but only if the municipalities get together on the planning project, which must be completed by 2010.

"I can't argue for big money if we don't have a plan to do this and do it in a way to do it right," he said. "We can't have one chink in the armor or it won't work."

John Schombert, executive director of 3 Rivers Wet Weather, said the nonprofit organization formed to work on the sewer problems recently completed mapping the 110,000 manholes and 4,000 miles of sewer lines in the Alcosan system and that information will be delivered to municipalities soon.

Mr. Schombert said his organization also did a regional flow monitoring plan for all 83 municipalities that saved $15 million by eliminating the duplication of having each municipality produce its own.

He said the municipalities have asked Alcosan to implement that plan by installing flow monitors and collecting data.

Alcosan and 1,100 other sewerage systems in the Northeast and Great Lakes regions are facing federal orders to stop wet weather overflows. And the EPA has previously cracked down on Atlanta, Seattle, Baltimore, Boston, Chicago, New York, Philadelphia and Erie, requiring them to clean up their sewage overflows.

Many of those systems, as well as the Alcosan system, were designed to overflow during storms to prevent damage to treatment facilities. Subsequent changes in federal law have made those overflows illegal.

Alcosan and the EPA are continuing to negotiate on a consent decree to fix the wet weather overflow problems. Mr. Onorato said they've reached agreement on planning and repair issues but are still negotiating on penalties.

Renee Searfoss, an environmental scientist and EPA's head negotiator with Alcosan on technical issues, wouldn't comment on the substance of the negotiations except to say there has been recent movement and "a handful of issues still need to be addressed."

Alcosan wants to see any fines or financial penalties plowed back into the sewer system repairs. That wasn't done, however, with previous penalty assessments and some believe it could create a precedent that would limit future federal sewer system enforcement efforts.