On the Hunt for Water Leaks in London

Late at night on a quiet London street, workers in high-vis clothing put their ears to the ground. Lit up by the glare of headlights from passing cars, they face each other and shuffle in a steady sideways procession. One is wearing a large pair of headphones; his attention is fixed on a small LED screen. Another carries a device resembling an oversized plunger, which he lifts and replaces gently on the ground as they move.

These are London’s leak hunters, constantly listening to the city’s underground world for wear, tear and breaks in its massive network of water pipes. This particular crew comes from Thames Water, which has more than 800 workers either pinpointing the locations of suspected leaks or fixing the ones that get discovered. The company’s 13,000 square-kilometer (5,000-square mile) remit includes central London and extends from Gloucestershire in the west of England through to parts of Kent and Essex in the east. Thames Water repairs more than 1,300 leaks per week, one every seven and a half minutes.