A Nose for the InvisibleSix months ago, Saltillo’s water utility launched an experiment that sounded more like a children’s story than a public-works plan: let a dog find what engineers can’t see. Saltillo’s utility, Aguas de Saltillo, operates 190 network sensors watching flow and pressure in real time. The recovered flow: 14 liters per second, or more than 1.2 million liters daily. Saltillo’s supply comes entirely from aquifers—centuries-old reserves now draining faster than they refill. Saltillo’s water security did not improve because of a megaproject.