Ninety-six times last year, during summer rains or snowmelts, raw sewage and industrial wastewater from in and around the city were piped directly into the Conestoga River without being treated.

Some 943 million gallons of combined sewage and rainwater were discharged into the river and eventually the Chesapeake Bay.

That was a good year. In a wet 2006, more than 1 billion gallons of untreated water was released into the river.

Like about 800 other older cities around the country, the city is burdened with an antiquated Civil War-era underground pipe system.

Curbside storm-water drains, basement sump pumps, industrial wastewater and sewage all drain together.

During rainfalls — usually one-tenth of an inch but sometimes as little as one-hundredth of an inch — storm water gushing off mostly impervious surfaces overwhelms the system. It can't be pumped to the sewage plant at Engleside for pollution treatment.

City officials said their tests repeatedly show that pollution and sewage sent into the river is diluted and water-quality standards are not violated, though levels of fecal coliform — a bacteria from feces — are temporarily raised.

Just 1 percent of the discharge, on average, is raw sewage, said Bryan Harner, the city's wastewater project manager.

"The discharges are not deteriorating the stream. But we also recognize that's still a lot of pollution that might not hurt the stream locally, but in the Chesapeake Bay, that's a lot of nutrients," said Charlotte Katzenmoyer, the city's public works director.

State and federal agencies have been sympathetic to the city's plight. Building hundreds of miles of separate sewage and storm-water lines under city streets is prohibitive. The agencies have permitted the unsavory discharges while the city works on the problem.

But now the pressure is mounting.

Citing violations of the federal Clean Water Act, the U.S. Environmental Protection Agency recently ordered the city to list how it will correct the problem and to attach specific completion dates.

 The city has compiled a plan and will meet with EPA officials within two months.

"The ultimate goal is to slowly reduce combined sewer overflows and eventually eliminate it," Harner said.

It will take years, it will be expensive and it will result in higher sewer bills for customers in the city as well as for users in East Lampeter, Lancaster and Manheim townships.

"Yes, there will have to be," Katzenmoyer said, when asked if sewer bills will be raised to help pay to fix the problem.

Owners of large impervious surfaces, such as parking lots, would pay more than homeowners, Katzenmoyer said.

One of the possible big-ticket items: $70 million to build a massive 10,000-gallon storage tank to store runoff until it can be pumped to the sewage plant and treated. The facility would be built on vacant ground near the city's water plant and Pitney Road.

If EPA agrees that the storage system is the best answer to the combined sewer system overflow problem, the project would likely go forward, Katzenmoyer said.

The city has already received $3 million in state and federal grants to do preliminary engineering work on the storage tank.

Other measures the city has proposed include upgrades to the four pumping stations along the river, where storm water is currently sent directly into the river.

That would allow more wastewater to be sent to the sewage plant, which also would undergo changes to handle more of the runoff.

Some $15 million in upgrades to the North pumping station near the water treatment plant and the Stevens pumping station off Chesapeake Street are scheduled to be complete by 2011.

That will allow up to 19 million gallons of storm water to be sent to the sewage treatment plant. And in February, a $385,000 upgrade was completed that enables up to 15 million gallons of overflow to at least be screened for debris and get a dose of chlorine before being discharged.

Stormwater also is discharged into the river at the Engleside treatment plant and at two spots near Central Park and Strawberry Street.

 Another key component of the city's fix-it strategy is deployment of a citywide green infrastructure plan involving everyone from homeowners to businesses.

Green roofs, rain gardens, tree plantings, porous pavement, rain barrels and other measures would be encouraged with perhaps financial incentives.

Public meetings on the plan, which also is being done to save energy, will be held within the next several months.

"It's going to be a holistic approach," Katzenmoyer said of the stormwater strategy. "We can't spend our way out of this problem."

E-mail: acrable@lnpnews.com