Using sound to find leaks and save dollars

November 25, 2011

Sarah Lu

Download Story

While fresh water is abundant in our region, water loss has an economic cost. It is common for local water utilities to lose between ten and twenty percent of treated drinking water in transmission due to leaky underground pipes. To cut down on water loss, some local utilities have formed their own leak investigation units.

Illinois American Water in Woodridge created a leak investigation department about two years ago. To see what a day in the life of a leak detector is like, I meet up with supervisor Tim Morris and his crew on a quiet tree-lined street in Bolingbrook.

“We received a phone call from a customer, saying that they found that their parkway was saturated.” Morris says.

We survey this customer's front lawn, and a small patch of grass squishes under my feet.

The customer comes out to talk to us. He points to the squishy area and says, “There’s water all the time here. It all comes up over here"

The water in his lawn could be groundwater that collects there because of a drainage issue. But if it’s a leaky pipe, Morris and his crew can help by pin-pointing the cause. We can see that there might be a leak, but to find the possible source, Morris’s crew relies on sound.

They place a sensitive microphone called an “X Mic” directly onto the closest fire hydrant.

“We’re trying to listen to find the leak,” Morris says.

A loud squealing sound is a sure sign of a major leak. I hear a quieter sound, which tells us there couldbe a small leak. To further their investigation, Morris and his crew use another piece of equipment that measures sound waves. It’s called a correlater.

One correlater box is attached to the fire hydrant. Another correlater box is attached to a valve at the end of a pipe about one hundred feet away.

“What they’re doing is they’re sending signals back and forth to each other, trying to find out where they’re losing the frequency that they’re initially sending out,” Morris says as he looks at the correlater readings on a small screen. “You can see from our graph that it’s about twenty-six feet from the red spot there.”

Morris’s crew mate Skip Semetulskis marks the spot. It’s about ten feet away from the saturated, squishy ground where we first saw evidence of a leak.

Morris says,“You know, if the maintenance crew had come out here before we did any kind of work, they would have dug right here. They would have dug, and if this hadn’t been the spot, then they would have trenched. So now if everything else leads it to being at that point, we dig right there, it ends up being right there, then that just saved us ten feet of excavation. That’s time, that’s money, and that’s the customer’s inconvenience. We were able to limit that. “

In this way, a proactive approach to leak detection reduces the costs of recouping lost water.

Morris says that eventually, the Leak Detection Department at Illinois American will pay for itself. Since they started, they have already saved a lot of water.

“My team has been able to save a loss of tens of millions of gallons over the last year and a half. Less than ten percent of all the earth’s water is drinkable. Lake Michigan itself is constantly losing water. It is a limited resource. I take my job at a very personal level. I love what I do."