BETHESDA, Md. -- Officials said it will be at least another day until a water boil advisory is lifted for parts of Montgomery County.

Residents in an area ranging from Germantown and Gaithersburg to Olney and Burtonsville were placed under an advisory following a major water main break on Sunday that knocked out service to tens of thousands of customers. Poolesville and Rockville are exceptions.

The Washington Suburban Sanitary Commission said Tuesday that the Maryland Department of the Environment has requested a second round of tests before the boil advisory can be lifted, meaning the advisory will be canceled Wednesday night at the very earliest.

A drinking water station will operate on Tuesday from 5 p.m. to 10 p.m. at the Rockville Senior Center at 1150 Carnation Drive. People can get clean water there for free, but they are asked to bring their own containers. The center will open at 7 a.m. on Wednesday and remain open from 7 a.m. to 10 p.m. daily until the boil advisory is lifted, the city said.

1,200 Food Establishments Closed

Montgomery County on Monday ordered about 1,200 food establishments that use water from the WSSC to close, News4's Darcy Spencer reported. About 900 of the businesses are restaurants, and the remaining 300 include markets and mobile food services.

Signs were posted in English and Spanish at the food establishments ordering them to close or face fines. At a McDonald's in Gaithersburg, puzzled drivers circled the drivethru, wondering why it was closed.

Fillippo Leo at Marchone's Italian Specialties found out about the closure during lunch. He said the restaurant had already prepared food, which had to be thrown away.

"One day is bad. Two days is almost just death to a couple of places," said Lee Howard, who owns the Urban Burger Company near Rockville.

"It's business that you can't make up," Howard said. He said he loses about $3,000 each day his restaurant is closed.

Brian Marshall, owner of Outta the Way Cafe in Derwood, wondered how long the county's order to close their businesses might last. "We're going shift by shift," he said.

Just down the road, Hever Lizama, owner of Biscotti Ristorante Italiano, said he could have easily boiled pasta in bottled water and wondered if the restrictions were really necessary.

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"Where I come from, people drink dirty water every day," said Lizama, originally from El Salvador.

Montgomery County Executive Isiah Leggett said the move is necessary to avoid possible water contamination and harm to citizens.

A Safeway store on Georgia Avenue had a tanker truck filled with fresh water come to the store so it could stay open and wash perishable food for customers.

Boil Advisory In Effect

A boil advisory will remain in place until at least Wednesday, officials said. The results of the first round of water tests are not expected until the early morning hours on Wednesday. Results of a second round of tests, which were conducted on Tuesday, take 24 hours to process.

A hot line has been set up for those affected by the advisory. The number is 240-777-4200. Residents can also visit WSSC's Web site to see a map of affected areas.

Water should be brought to a rolling boil for one minute before using. Boiled or bottled water should be used for drinking, making ice, washing dishes, brushing teeth and food preparation.

Water should be boiled even if residents have filtration systems in their homes, News4's Liz Crenshaw reported. It should be stored in clean, covered containers.

Ice made with possibly contaminated water should be thrown away, Crenshaw said. Pet owners should also boil water for their animals. Hot water from the dishwasher may not be sufficient to kill bacteria, so dishes should be hand washed with boiled water.

WSSC spokesman John White said the best way residents can help is to run their water for at least three minutes to help flush dirty water out of the system.

People should contact their doctors is they experience nausea, fatigue, stomach cramps or diarrhea, Crenshaw said. People with weakened immune systems will experience more severe symptoms.

WSSC will lift the boil alert, and the health department will allow restaurants to reopen only if the results show the water is safe.

Residents said they are stocking up on bottled water. Some said they are worried about whether they should shower. Others have gone to friends' and relatives' houses to shower and have resorted to brushing their teeth at work. WSSC officials said bathing and showering in the water is safe.

Toni Woods, 54, and her mother were loading a few water bottles into their truck outside a Giant in Gaithersburg. Woods, who is disabled, said the water restrictions would cause financial strain in a high-cost area for the family since the hospital coffee shop where her daughter works had to close.

"We need the money to pay for our apartment and our utilities," she said.

Breaks Sign Of Aging Infrastructure, Some Say

The water main break follows a series of recent disruptions for Washington area residents, including a blackout in downtown Washington, a Metro subway train derailment and track damage caused by the heat.

"What we've seen in the Washington area in the last couple of weeks underscores what a lot of folks have been warning for some time: We don't have a good policy or funding mechanism in place in America or the national capital region to invest in infrastructure," said David Robertson, executive director of the Metropolitan Washington Council of Governments.

WSSC, the eighth-largest water utility in the country, has warned that its system is aging, overtaxed and underfunded. It now serves 1.8 million suburban Maryland customers, and it has suffered an increasing number of water main breaks. In 2007, it had a record 2,129.

The utility estimates that by 2025 about half of its infrastructure will have reached its useful life.

"We're faced with aging pipes, aging infrastructure," White said. "We've tried to fix the problem as best we can, given the limited funds we have."

More Water Mains Rupture After Major Break Sunday

WSSC worked to repair more water main breaks in Montgomery County on Tuesday morning.

The first break happened at about 4:30 a.m. in the 4600 block of Overbrook Road in Bethesda. Water was shut off to the 16-inch water main, and about 57 customers in the area were affected.

WSSC said crews also worked to clean up another leak in the 8300 block of Piney Branch Road, which affected about 25 customers and two restaurants.

Water to the 16-inch pipe was shut down at 6:30 a.m., officials said. It is in the same area where there was a water main break last Thursday, according to the WSSC. Officials said part of Piney Branch may eventually need to be closed to traffic.

The small breaks came after a 48-inch pipe ruptured Sunday just after 9 p.m. near Rockville Regional Park at Muncaster Mill Road and Meadowside Lane, sending 100 million of gallons of water pouring into nearby Rock Creek.

Jim Nuestadt, a spokesman for the commission, said a large number of people were affected, but he didn't have a specific number.

"People were feeling it all over Montgomery County," he said.

Nuestadt said a drop in water pressure was first noticed Sunday night, but the break wasn't pinpointed until Monday morning in a wooded area of the park. Initially, authorities thought the break was in a 36-inch water main that runs parallel to the broken pipe, which was 38 years old.

WSSC reported that service had been restored to customers throughout the county by about 9 p.m. on Monday.

The major break also caused smaller pipes, such as one at Muncaster Mill and Redland roads, to rupture, sending water bubbling up onto roads. Traffic was disrupted Monday morning while crews repaired the leak. About 80 customers were affected.