Many were surprised in late July when the US state of Minnesota reported that more than 30 of its state water systems had faced a "co-ordinated cyber-attack". Days later, the FBI warned cyber-attacks had been reported in at least seven states and "some of that activity degraded water operations". Local authorities in the states of New Jersey, South Dakota and Georgia have since said they were similarly attacked. It is not clear if they are among the seven states. The US has 152,000 public drinking water systems and more than 16,000 wastewater treatment facilities.