Starting December 11, Waitsfield’s municipal water system began losing some 60,000 gallons a day and water system operator Nate Fredericks said the leak is unusually large and unusually hard to find.
The water loss of up to 60,000 gallons a day has prompted an intensive investigation by Fredericks of Simon Operating Services. Fredericks, said data from the municipal water tank first showed signs of trouble around December 11, when the tank began draining far faster than normal after the well pump shut off. Before then, the system averaged about 44,000 gallons a day in use. Since mid-December, that number has jumped to between 100,000 and 115,000 gallons daily.
“The tank level was dropping much faster than it had been,” Fredericks said. “That was pretty obvious.”
GRAVITY FED
Waitsfield’s system is gravity-fed: water is pumped from a well on Ronk Road to a storage tank on Bushnell Road, then flows downhill to customers without additional pumps. Using electronic monitoring and alarms tied to the tank, Fredericks can track changes in water levels and estimate how much water is leaving the system.
What he cannot yet see is where it’s going.
The town does not have a master flow meter after the tank, but individual services – including high-use customers such as housing developments, trailer parks and large users like the Eagles – are metered. None show abnormal usage, suggesting the water is not being lost after customer meters.
SURFACE QUICKLY
Based on monitoring and assistance from the Vermont Rural Water Association, the leak is estimated at 20 to 45 gallons per minute – a significant amount that would normally surface quickly.
“That rate is a lot,” Fredericks said. “Usually, you’d find a leak like this by now.”
Fredericks and staff have already listened to all 27 hydrants in town and most mainline valves using acoustic leak detection equipment, including sophisticated correlators that compare sound signals along a pipe to pinpoint leaks. The effort has come up empty.
Part of the challenge, Fredericks said, is Waitsfield’s infrastructure. About 90% of the system, including most service lines, is made of plastic pipe, which does not transmit sound as well as ductile iron.
SPECIFIC NOISE
“Water makes a very specific noise when it’s leaking,” he said. “Plastic pipe doesn’t resonate the same way, especially depending on how it’s bedded in the soil.”
Another complicating factor is geography. The water system crosses several streams and rivers, in some places without nearby valves that would allow crews to listen directly to the pipe.
“It could be under a stream,” Fredericks said. “It could also be leaking and following the pipe itself, which is a natural conduit, until it finds a place where the water can move through gravel or soil and eventually reach a stream.”
ISOLATING
Because the leak has not surfaced, Fredericks said it is possible the water is traveling underground before emerging far from the actual break – or not visibly at all.
To narrow the search, the town will begin systematically isolating sections of the water system during overnight hours when usage is low. The work involves manually closing valves to shut off portions of the system, then watching the tank level in real time through electronic monitoring equipment.
The process will take place between roughly 2 and 4 a.m. on several nights, including early Friday morning, January 23, Tuesday night into Wednesday morning, January 28 and possibly later if needed. During those windows, some residents may experience temporary water shutoffs.
The strategy is straightforward: shut off about half the town, watch the tank, and see whether the rate of loss changes.
SECTION BY SECTION
“If the tank level doesn’t drop as expected, then you know the leak is on the other side,” Fredericks said. “Then you keep moving, section by section, closer to the tank.”
He said only one section will be isolated at a time to ensure the data clearly points to a specific area. Valves are operated manually using a wrench, and the work is done slowly to avoid pressure problems.
As a precaution, the system is being chlorinated during the isolation work to protect against the small risk of contamination if pressure drops near the leak.
Fredericks emphasized that Waitsfield’s water system has been well maintained and largely trouble-free for more than a decade. The last major incident occurred in 2013, when a contractor accidentally drilled into a pipe beneath a river – a break that was quickly identified and repaired.
UNUSUAL
“This is pretty unusual,” he said. “What’s not typical is how it’s not surfacing.”
Fredericks said he is confident the leak will eventually be found, either through isolation or because it finally reveals itself above ground. When that happens, repairs may require shutting off water to a smaller area and issuing a boil-water notice for affected customers.
“At this point, we haven’t found it, so we’re not cutting into the pipe,” he said. “But once we do, we’ll take the steps we need to fix it safely.”
You might also like
