Carrying a blowtorch and a piece of copper tubing, Bill Lewis waded into the five-inch pool of water that had collected in the Silver Spring apartment building. Once again, he was ready to do battle with a pipe that had frozen, ruptured and then begun to leak.

Lewis, a Montgomery County plumber, has postponed calls for nonessential jobs such as clogged sinks and put in 10-hour days for more than a week. He is up to his neck, or at least his ankles, in work.

"You get high winds and cold weather and you'll get flooded with calls about broken pipes," says Lewis. In fact, the extreme cold this month has taken such a heavy toll in broken pipes and flooded basements that finding a plumber this week anywhere in the Washington area is about as easy as persuading a doctor to make a house call.

Thomas E. Clark Inc., a Chevy Chase plumbing company, has repaired about 200 broken water pipes in Washington area homes since the freeze hit two weeks ago. "And 200 is a conservative estimate," said company president Thomas E. Clark Jr. He said another 50 customers have their water shut off waiting for Clark plumbers to come and fix the leaks.

James J. Madden Inc., which handles business and commercial accounts, has had 36 plumbers working around the clock to repair "thousands of pipes" damaged by the January weather. "One building we have is literally gone--we must repipe it," said John P. Madden, the company president.

In just one day this week, George F. Warner & Co. recorded 300 calls from customers with broken water pipes. David Warner, one of the owners, said the company sent out plumbers on 150 of the calls but did not have the manpower to handle the other 150, who were told to call other firms.

Warner says there have been more broken pipe calls this winter "because the weather has been worse than usual." And local authorities warned yesterday that there may be more pipe problems in the days ahead if the Washington area gets another freeze.

"Since there are so many pipes that are on the fringe of being frozen now, another freeze could get them," said Marjorie Johnson, public affairs director for the Washington Suburban Sanitary Commission, which provides water and sewer services for Montgomery and Prince George's counties.

According to Johnson, there is one way to keep pipes from freezing: "Leave the cold water faucet at the lowest level in your house--the basement--running at a trickle. That slight movement will prevent freezing."

During the eight-day period that ended Jan. 18, the WSSC had 114 broken water mains--three times the normal breaks for this time of year--and 275 emergency turnoffs for customers whose pipes had frozen and burst. In addition, the agency received 612 calls from customers saying they had no water because of frozen pipes. WSSC was responsible for the pipes involved in 82 of those no-water calls; property owners were responsible for the other 530.

At the District of Columbia's Bureau of Water Services, the water distribution division estimates it has received 5,000 calls over the past 10 days from residents complaining that they either had no water because of frozen pipes or that their pipes had burst because of the freeze. "We have crews working 16 hours a day," said George Papadopoulos, deputy chief of the distribution division.

Water pipe problems for area residents typically begin with high winds and low temperatures that can freeze the water in the pipes that lead from the ground to the home or office. Those pipes usually snake through the walls and under the floors. If there is a leak in the outside wall or masonry permitting wind to get through to the water pipe, it can result in the water in the pipe freezing.

"When anybody calls me and says their water pipe is frozen, I tell them there's nothing to do but wait until it thaws," says Lewis. In some cases, water in the pipe thaws and begins to run normally, with no damage to the pipe. Sometimes the thawing can be speeded up by using a hair dryer or a heating pad on the frozen pipe, but local officials warn that blow torches and candles should never be used..

Pipe ruptures occur as the water in the pipe freezes and expands. Then, when the water thaws, the broken pipe begins leaking.

In this case of the Silver Spring apartment building, the broken pipe was exposed and easy for Lewis to reach. "If you had to order a leak, that would have been it," he said. After using a blowtorch to unsweat the joints of the ruptured piece, he soldered a new piece in place. The job would have been more difficult, he said, if the ruptured pipe had been hidden behind a wall.

Difficult or not, Lewis says, broken pipe jobs are not making him rich.

"Labor charges pays for my overhead," he says, "but you have to sell material--like a hot water boiler--to make any money."