San Francisco uses tech to find leaky pipes

In the image below, water technician John Bess (left) of M.E. Simpson and Adam McKnight of Pure Technologies listen to a leak which can be heard in a hydrant installed in 1909. San Francisco, CA water officials are employing some new high technology to detect leaks in the city's aging underground pipes and hydrants. John, from Baltimore, has spent the past two weeks walking around San Francisco with his headphones and Orioles cap on. He’s logged nearly 10 miles a day. 

Photo by Brant Ward, The S.F. Chronicle

But Bess is no tourist. He’s searching for water leaks in the city’s underground pipelines with a special microphone and earpiece that enables him to hear escaping water from the street – rather than having to dig down and find it. The first leak Bess found was at a pipe beneath North Beach. It was spilling an estimated 21,000 gallons of water a day, booming a telling signal to his headphones. “Remember the old TVs when you would get static and there’s a whole bunch of snow? That’s how it sounds,” he said.

California water agencies lose an average of 10% of their water to leaks, according to state data. While some breaks are obvious, such as when a water main blows and floods a street, many are deep in the ground and hard to detect. With a fourth year of drought looming, officials at many water departments are taking extra steps to make sure their pipes are free of glitches big and small. San Francisco’s $400,000 effort to test – and ultimately acquire – new acoustic-monitoring technology aims to find the biggest hidden leaks with the least amount of time and money.

With more than 1,200 miles of pipeline beneath city streets, water officials are focusing their initial inspections on about 130 miles of cast iron lines that deliver water exclusively to firefighters. These high-pressure pipes, between 10 and 12 inches in diameter and running about 4 feet beneath the street on the eastern side of the city, date to just after the 1906 earthquake. They contain the same water that’s piped to homes and businesses and originates mostly at Yosemite’s Hetch Hetchy reservoir.

Bess, of M.E. Simpson Co. headquartered in Valparaiso, Indiana, attaches his mike to either a hydrant or a valve accessible from the street and listens for the telltale sound of a leaking pipe. When the sound is detected, as was the case near the intersection of Union and Front streets this month, they use a specialized computer to measure how long it takes for the sound of the leak to travel to the surface, allowing them to pinpoint the exact location of the faulty pipe.

The city’s leak-detection program is being managed by Pure Technologies, based in Canada, which has worked with other cities to reduce water waste. The company plans to use other detection equipment to fully assess the condition of city pipes once the acoustic work is complete – and the biggest leaks repaired. With about half of the old firefighting pipelines examined, two major leaks have been detected. From a San Francisco Chronicle article by Kurtis Alexander, March 2015.