New Delhi, Aug. 2 -- the equipment that monitors treatment, regulates pressure, and ensures that what comes out of the tap has been processed correctly. Michigan officials confirmed this week that hackers had targeted those controls at nine water systems across the state. Minnesota had disclosed attacks on 30 water-related sites several days earlier. Federal authorities said the incidents extended to at least seven states in total, and the FBI was investigating what it described as a coordinated campaign against one of the most basic categories of American infrastructure.

The water kept flowing. Dale George, the communications director for Michigan's Department of Environment, Great Lakes and Energy, said the state's water systems contin...