West Virginia and Ohio communities filled swimming pools and bathtubs with precious water and stockpiled ice cubes yesterday as a 20-mile-long oil slick rolled down the Ohio river, fouling the drinking water supply of millions.

In the Pittsburgh suburbs, many residents celebrated the first flow from household taps in three days, toasting with glasses of water and taking baths. At least partial service has been restored for nearly all 750,000 residents short of water since an Ashland Oil Co. tank 25 miles upstream cracked Saturday, spewing a million gallons of diesel fuel into the Monongahela River, which flows into the Ohio.

As the smelly slick coursed down the Ohio River within a few miles of Wheeling, W.Va., last night, a 100-member oil mop-up crew was forced to pull work boats from the Monongahela and Ohio because of the thin layer of ice covering them.

The longer the oil remains in the water, the more of it will dissolve, preventing removal, Coast Guard spokesman Todd Nelson said. "It's going to continue downstream, and there will be more of a loss to the environment," he said. "We're talking about damage to the water, to the adjacent areas and the wildlife."

From the Ashland terminal in Floreffe, Pa., the oily sheet has glided past Pittsburgh and down the Ohio 115 miles from the accident. The oil dilutes as it moves downstream, but still represents a public health threat to the communities that draw water from the rivers instead of underground wells, said Environmental Protection Agency spokesman Lorraine Urbiet.

When the town of Wheeling shuts off its intake from the Ohio as expected early today, it will be the eighth municipal or private water supplier forced to stop operations since the accident. Three have resumed pumping from the rivers, removing the pollutant with an extra dose of chemicals.

In East Liverpool, Ohio, the water was successfully treated with bentonite, a clay-like mineral that attracts oil, said Curt Ridenour, a state water specialist. The oil is allowed to settle, and the water is mixed with activated carbon, which removes more pollutants. An oxidizing agent removes flavor and odor, he said.

Thirty miles downstream in Steubenville, Ohio, Mayor Dave Hindman said chemists are adopting the same formula in the hope of cleansing the water enough to resume service today. Since the town cut off its intake Wednesday, 50,000 residents have lived off the water left in distribution lines. Two 500,000-gallon swimming pools filled in anticipation of the drought serve as backup supply for the town's fire department and hospitals, he said.

But when flames burst from a red-frame house yesterday, Fire Chief John Mencer said firefighters "basically let it burn," the Los Angeles Times quoted him as saying. Mencer said the house could not have been saved, but a neighbor, Dayle Grimm, disagreed. "I know we're uptight about water," she told the Times, "but when somebody's house is on the line, I think there should be exceptions."

In Wheeling, a town inured to disasters caused by flooding and major fires, city officials began making elaborate contigency plan days ago. Pipes were stretched across the river into Ohio, hooking up with communities that draw water from wells. Four barges are waiting to receive water from a clean creek. Car washes and laundries were directed to close and residents asked to stockpile water.

"People are really preparing for the worst," said Nancy Vapner, assistant city manager. "They're filling bathtubs, filling up garbage cans and making ice cubes they can thaw. The Kroger {grocery store} has been out of bottled water for days."

They may have drawn a lesson from the experience of Robinson Township, outside Pittsburgh, where 20,000 residents ran dry Monday night and have spent most of their time since lugging water from tanks provided by the National Guard.

When partial water service resumed yesterday morning, Joseph Cialelli said, "I sang a little song -- 'Water, water, at last.' " Then, he took a hot bath.

"It just helps us know these things are important," Helen Batic, another Robinson resident, said of the shortage. "We shouldn't take water for granted. It can be taken away from you at any time."

Staff writer Cass Peterson contributed to this report.