Listening for Leaks

Proactive teamwork helps California water district prioritize projects and cut water loss.

Listening for Leaks

Utility systems specialist Kevin Barkdull, a member of the Marin Municipal Water District’s Leak Detection Team, uses a ground mic to listen for leaks in a waterline. Above:

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Almost 30,000 gallons per day — that’s how much water is saved by the leak detection team of Marin Municipal Water District.

Formed in 2008, the Marin Municipal Water District leak detection team in Marin, California, is the result of a political push to formalize leak mitigation efforts that had been ongoing for decades. The team consists of two water systems technicians who survey the 887-mile system on a three-year schedule.

“The main part of the leak detection team is surveying — we pick a town, and then we just go up and down the streets, cover the whole town, and we listen to all the water services,” says Julian Barrolaza, water systems technician. “That’s what we do every day, and after we finish one town, we go to the next one. So then after three years or so, in theory, we have covered the whole district, and we start over again.”

The district’s proactive approach, in addition to a responsive unit of water systems specialists and service crews, saves a significant volume of water in addition to preventing an unknowable number of future line breaks and major leaks.

“The leak detection program is focused on the leaks that are not visible, that nobody’s calling in,” says Ben Bauer, leak detection field supervisor. “We don’t even know they exist until we walk by and hear something.”

Building a team

The two-man team consists of Barrolaza, who has been part of the team since its origins, and Jesse Obrochta, who joined the team about a year ago. The other original tech was Kevin Barkdull, who is now a specialist, responding to major leaks instead of surveying.

“There are a lot of ways to find a leak, and all the technology around finding leaks is about listening,” Bauer says. “Whether we do that with our naked ear, with a small metal rod, or an amplifier or a computer, it’s all around the noise that the pipeline makes. The water leaks through and vibrates the pipe, and it makes a sound.”

Knowledge of pipe materials is the biggest criteria for a capable leak detection crew — no small feat in a county that started laying pipe about 150 years ago, with material ranging from copper, galvanized, and cast iron pipe to asbestos cement pipe and PVC. In new construction, the district uses only welded steel and PVC.

“It’s trial by fire. It’s mostly learnt on the job, but my past experience has led me here,” Obrochta says. “A qualified candidate knows the system, knows the pipe materials, and then works closely with the other leak detector — and you’re off and running.”

Obrochta and Barrolaza both started as laborers and learned the necessary skills to transition into leak detection. “As a laborer on the service crews, you’re out there fixing leaks, learning about materials,” Obrochta says. “You get knowledgeable by fixing all these leaks before you can start to find them.”

Marin nearly always recruits from within for the leak detection team, and it seems to be working out.

“Roughly in the last calendar year, we found 20 leaks on the residential pipelines, and we found 26 Marin Municipal Water District leaks,” Bauer says. “We estimate loss, and by fixing those 26 district leaks, we think we’ve saved 28,800 gallons per day.”

A separate water conservation department handles customer education, but the team contributes where they can.

“When we run across consumer leaks, we try to meet with those consumers and let them know what’s going on,” Barkdull says. “If they’re not at home, we leave them a door hanger stating what’s going on, and they have a number to contact us.”

Survey and save

Any aboveground extension of the water system that can channel vibration is a possible listening point. From there, with the proper tools, even a dripping faucet can be detected.

“Basically you’re picking a spot, and you’re putting on your listening equipment; you’re listening on the water meters, the water valves, hydrants, anything that you can listen on,” Barkdull says. “The best way to describe it is like taking a balloon, blowing it up and letting that air squeal out the end of it. Really what you’re hearing is the pressure pushing out of the pipe, out of the leak.”

There are basic manual devices, like metal rods, that are essentially naked-ear listening — unassisted by technology. Beyond that, electronics like amplifiers, correlators, and leak loggers can assist in diagnosing and pinpointing tricky leaks, especially when dealing with difficult materials.

“The PVC and the plastic — they don’t make the same noise as the metal pipe. Same thing with the asbestos cement pipe — they just don’t have the noise,” Barkdull says. “We do have sensors on our correlator that are a little more sensitive, that can help us locate. It depends a lot on the ground, too. We’ve got a lot of adobe clay out here, and that can muffle the noise.”

Amplifiers are pretty self-explanatory, but leak loggers and correlators are a little more advanced. They can be deployed for longer periods of time, so the computer program can listen for and dismiss any inconsistent sound over the deployment period, leaving only the sound of leaks.

They can also use sensors at different points along a pipeline to pinpoint a leak, essentially giving the operators a series of data points — the distance of the leak from each sensor. With multiple reference points, they can narrow the location more quickly.

Sensors like the leak loggers have the capacity for long-term deployment, but that doesn’t always prove to be the best system.

“We’ve tried to deploy these long-term, but our biggest success has been to deploy them short-term,” Bauer says. “We’re able to maximize the loggers that we have, because if you put them out permanently, you need thousands of these things. So we have a small number that we’re able to deploy on a short-term basis.”

When looking for leaks, there are several steps between the team and service crews. First they have to determine whether it’s a consumer or district leak. Consumer leaks are obviously the homeowners’ responsibility, though the team tries to identify the leak and inform the customer.

“We do our best to pinpoint where the water is coming from, whether it be groundwater or whether it be a consumer leak, a district leak,” Barkdull says. Often they will shut water down on the consumer side to determine which part of the system a leak is coming from.

After that, a rating system determines the priority of the repair. Using a three-point scale, they determine if it needs to be repaired right away, by the next available crew, or if it can wait to be folded into the repair schedule.

A big asset in this process is the ArcGIS system (Esri) that the team uses to map leaks, log job information and manage the survey schedule. The custom map can be highlighted as they complete their survey, eliminating overlap and ensuring efficiency.

“You need to have the right tools,” Barrolaza says. “It is basically just listening, but you need to have really good-quality equipment. You can’t scrimp on these listening devices — you need to start with the right stuff.”

Marin Municipal Water District uses leak detectors and correlators from SubSurface Instruments and leak loggers made by Gutermann. With such varied equipment and complex tools, it’s a lot to take on for a team of two, but they aren’t on their own.

“We work well with our distributors for our technologies, too,” Bauer says. “They’re really good about coming to Marin Municipal Water District and answering any questions, reviewing the next great thing, or if we have any questions about some of the data that we’re recovering, they can help us analyze that and use those tools to their maximum.”

Eye toward the future

Technology is constantly advancing, and the Marin Municipal Water District is committed to keeping up with industry trends to provide the best service and water conservation possible. After finding that the long-term deployment of correlator sensors was not feasible, the district looked toward advanced metering.

“The idea that the meter might be able to pick up a leak sounds great — it’s never going to replace an actual, physical investigation by an employee of the district. I don’t see that happening,” Bauer says. “We’re going to have to confirm what the data is, go out and check conditions, and then move from there.”

The Marin Municipal Water District recently installed 2,000 new automation-capable meters from Badger Meter as part of a pilot program. The meters are able to automatically and remotely report consumer water usage numbers and could be used for leak detection purposes.

Consumer usage reports are already examined by the leak detection team to determine if a potential leak is on the district or consumer side. If a spike in water usage coincides with a suspected leak, it can be a pretty good indicator of where they should look. Using the smart meters to automatically report those spikes could create efficiencies for the program, essentially taking much of the consumer-side burden off the team’s hands.

The pilot program is doing exactly that, diagnosing potential leaks and alerting customers. In addition, customers can track their own water use through the meters with an online portal.

“I will say that the leak detection program cannot be completely automated,” Bauer says. “I think the transition for a tech in the field — should we choose to go with all automated listening devices — is into retrieving and collecting all that data and looking at it. And so I think there’s always going to be a way for the team to continue to be a part of this leak detection program.”

The team is one part of the broader leak mitigation program under the auspices of the district, and new ways to increase efficiency are always on the horizon.

“We’re pretty happy with the results that we’re getting. I think the district needs to make a choice about how we’re going to implement the smart meters,” Bauer says. “That will drastically change the direction that we could go, but for the foreseeable future, I see this team continuing to work over the next decade.”

Worth the effort

For a district serving nearly 200,000 customers, with an average daily production of 21 mgd, 30,000 gpd may seem like a drop in the pond, but as drought conditions become more common, projects like these are essential.

“We’ve had a leak detection program informally for many years, since the drought in about 1976. It was never formalized until we had some climate changes that brought it to our attention again,” Bauer says. “We were going through a dry period in our climate. The board of directors wanted full-time people to look for leaks, to save water, because it wasn’t raining. That was at the political level, and we’ve been going pretty strong ever since.”

Every gallon saved is money saved, and over time, it all adds up for utilities that are willing to put in the extra effort.

“As far as water conservation, I think the most cost-effective way is to send out a crew and repair pipes. That saves the most water in the most cost-effective way,” Obrochta says. “We go hand in hand with water conservation, obviously, with the amount of gallons saved through finding and repairing leaking pipes.”

Proactive and reactive

No matter how proactive your utility is about finding and stopping small leaks before they become major issues, there will always be emergency situations that crop up. That’s why it’s important for any leak mitigation program to have both proactive and reactive facets.

In addition to their leak detection team, Marin Municipal Water District also has water systems specialists, who are called out when a visible leak or main break occurs.

“The specialist is a first responder, so they’re basically busy with big main breaks and customer complaints about water leakage,” says Jesse Obrochta, one of the water systems technicians. “Then there are the two techs who are out surveying, looking for small leaks.”

The district has five specialists on staff, responding to visible public leaks. They are obviously easier to find, so the specialists are in assessment mode instead of detection mode. Occasionally, though, even when water is surfacing, the source isn’t immediately clear, so the detection team will be called in with its equipment to assist.

“Leak detection spends a lot more time looking for the leaks that aren’t seen,” says Kevin Barkdull, water systems specialist. “They’re trying to pick up on leaks that are underground, that nobody knows about, that are just starting or possibly have been going for a while; whereas my job is responding to a lot of the leaks that are already showing.”

That all-encompassing approach to leak mitigation has proved very effective, saving the district almost 30,000 gallons a day.


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