As the streak of triple-digit heat continues, more water main breaks in North Texas are considered inevitable.
With the high temperatures, the ground starts to bake and the soil begins to move. Just as a house's foundation can suddenly develop cracks, so can the pipes carrying water to homes and businesses.
"When the heat gets so intense on a day-to-day basis, the soil starts shrinking and shifting," said Andrew Cronberg, assistant director of the Fort Worth Water Department. "And we start seeing an increase in breaks."
This month, much of east Fort Worth lost water pressure because of a main break at East Rosedale Street and South Beach Street, and there's no guarantee that more large mains won't break as the summer continues.
With 3,200 miles of waterlines and 3,100 miles of sewer lines, Fort Worth has a lot of opportunity for pipe breaks.
When a pipe 12 inches in diameter or smaller breaks, a repair can take only four to six hours. But when it's 16 inches or larger, the work can take much longer.
"We're usually looking at a minimum of 12 hours on the big pipes," said Water Department spokeswoman Mary Gugliuzza.
This month, Fort Worth has had 169 water main breaks, the most for a July since 2006. Part of the problem is that some cast-iron pipes are about a century old.
But the type of soil can also be a factor. Some neighborhoods have more corrosive soils, and some have soils that are more likely to contract in hot weather.
Another factor is the rise in water pressure as more water is pumped, increasing stress on the pipes.
This summer's problems pale in comparison with July 1998, when a 36-inch water main broke, leaving most of downtown and the Medical District without water. At the time, one Water Department official ranked it as the city's third- or fourth-worst water-related problem in modern history, behind the 1949 flood and the drought of the mid-1950s.
To prevent a repeat of 1998, the Water Department spends about $48 million on pipe replacements annually, including the city's program for putting in new utilities when streets are replaced.
How much pipe can be replaced in a given year varies greatly, depending on the size and how many breaks occur. Last winter had more breaks than this summer, with 332 in January and 205 in February during the bitter cold around the Super Bowl.
The all-time high for breaks occurred in winter 1983, with more than 100 a day as the temperature stayed below freezing for a prolonged period.
Other cities are also seeing water main breaks this summer -- just not at the same pace as Fort Worth.
Arlington, with nearly 1,410 miles of pipe, has about 21/2 breaks a day, said Julie Hunt, director of Arlington Water Utilities.
"We're having them, but it hasn't really reached an astronomical level at this point," Hunt said.
North Richland Hills, which has 356 miles of pipe, has averaged about one break a day over the last two weeks, city spokeswoman Mary Peters said. Most have been smaller pipes.
Bill Hanna, 817-390-7698