As water restrictions tighten, Dallas loses billions of gallons each year




Posted on May 3, 2012 at 10:51 PM

DALLAS - Some homeowners are worried their lawns are going to burn up this summer after last year's drought, and water restrictions across North Texas are meant to save as many drops as possible.

So they might be surprised to know the city loses billions and billions of gallons of water and dollars each year through its own pipeline system.

With a sensitive noise surveyor, Dallas Water Utilities (DWU) worker Elvis Perry confirmed exactly the location of a small leak.

"As you get closer to the water main itself, you'll notice the sound raises," he said.

The scratchy noise heard through the headsets is the sound of money.

With Dallas city hall lowering weekly watering to just twice a week, the pressure is on the city to do its part to save water. But one of the biggest ways that water is lost or wasted is from leaks right through the city's own system, long before the water ever gets to customers.

The leaks are tiny or towering.

Last year, Dallas Water Utilities lost more than 10 percent of clean treated water through its 5,000-mile network of pipelines at a cost of $10 million.

That's 16 billion gallons - enough to fill White Rock Lake almost three times.

Dallas City Council member Scott Griggs finds it hard to fathom.

"It seems like a really big number, and that's why this is a problem that we need to tackle," Griggs said.

Or, more likely, wade into.

Because with water vital, a passive approach is not an option, according to DWU Interim Assistant Director Randy Payton.

"Water loss is a fact of life," he said. "And like I said earlier, Dallas Water [Utilities] is doing its part in trying to get that water to the customer."

No longer does it rely on the low-tech way to find leaks - pushing a probe and then literally listening for them.

In 2005, the city started buying acoustic loggers, sensitive up to 500 feet, which cling by magnet to underground valves and amplify sound waves of a leak transmitted along the lines. Next, gadgets called correlators are set on each end of the water line, which listen and isolate the leak.

When the digging is almost done, Perry comes in with his sensitive surveyor and the probe placed on the pipe points to within inches of the leak.

DWU spent $1.8 million last year for six crews to proactively search for leaks. They found almost 300 while surveying 3,000 miles of pipeline.

But at that pace, it takes two-and-a-half years to cover the entire city.

Next year, it wants to spend $2.3 million for more crews and equipment. There is no inexpensive small leak anymore, according to Payton.

"Leaks like that can exist for up to two years, underground, unknown, unreported," Payton said. "That could be approximately 55 million gallons of water lost per leak."

Water rates are set to go higher for years, with a growing population, decades to build new reservoirs, and the next drought always sometime in the future.

The cost to saving water will only go up, too.