In the U.K., where some reservoirs ran dry this summer after heat waves and a lack of rain, more than 3 billion liters of water leaks from pipes every day. In Delhi, India, as much as 40% of water is lost to leaks. In California, where residents tried to cut water use at the height of a six-year drought, around 10% of water in cities leaks before it ever reaches homes.
A new low-cost robot, the U.S. winner of the 2018 James Dyson Award, is designed to find leaks in pipes early, both to save water and to avoid bigger damage later from bursting water mains. Called Lighthouse, the robot looks a little like a badminton birdie. A soft “skirt” on the device is covered with sensors. As it travels through pipes, propelled by the flowing water, suction tugs at the device when there’s a leak, and it records the location, making a map of critical leaks to fix.
MIT doctoral student You Wu spent six years developing the design, building on research that earlier students began under a project sponsored by a university in Saudi Arabia, where most drinking water comes from expensive desalination plants and around a third of it is lost to leaks. It took three years before he had a working prototype. “Basically, the first 10 versions were all failures,” says Wu. “We were getting a bit frustrated.”
Then Wu got inspiration from an unexpected source: At a party with his partner, he accidentally stepped on her dress. She noticed immediately, unsurprisingly, and Wu realized that he could use a similar skirt-like design on a robot so that the robot could detect subtle tugs from the suction at each leak.
While other leak-detection technology exists, it mostly relies on acoustics to find leaks–something that can work in suburbs, but doesn’t work well in noisy city centers. Some locations use plastic pipes, which can’t use acoustic detection at all. This is true in much of the South. “This basically means that for cities in Georgia or Virginia, the way they find leaks is to just wait until the water main breaks,” he says.
In a city like Boston, where around 50 water mains burst last year, a single break can cause $200,000 in damages to streets and property. The breaks typically begin when pipes shrink in the winter, and small, undetected leaks get worse. If the new technology lets the water company find and fix leaks early, Wu says, it could save 90% of the cost.
Wu graduated from MIT in June, and is now launching the technology through a startup called WatchTower Robotics. The company will soon begin pilots in Australia and in Cambridge, Massachusetts.
One challenge now, he says, is creating a guide so water companies can use the device on their own. Right now, Wu has to go in person to guide the robot through pipes. At a water hydrant, after shutting off the water, he pushes a robot into the water main, closes the hydrant, and then starts the water again to push the robot down the pipe to the next hydrant where it can be retrieved. At that point, the raw data from the robot can be analyzed by software to map leaks. It’s a process he’s still working to make more efficient.
Once the robot is in use, the maps it generates will tell water companies both where leaks are and how urgent they are. “The information is enough to help the water company decide if they should go and fix it now or if they could leave it for another couple of days or weeks before they have the manpower to fix it,” says Wu. Used at scale, this could make a large difference: Wu estimates that if half of the leaks in the world could be found and fixed, that would recover enough water to support 1 billion people.