Government officials are warning about a wave of cyberattacks on water utilities in the US. At least seven states have reported incidents to the FBI since July 27. The agency hasn't identified the attackers' motivation or identity, calling them only "malicious cyber actors" and saying they were remotely accessing internet-facing computers used by water utilities. The hackers changed settings, IP addresses, and passwords, the FBI said. In some cases, the attacks weakened the plant operators' ability to monitor and control their equipment. Cybersecurity experts have voiced concerns for years about cyber vulnerabilities in water systems and other critical infrastructure, such as energy and healthcare, including the possibility of attacks by foreign adversaries. In April, the FBI and other federal agencies warned about ongoing Iran-affiliated cyber threats, including those targeting water systems. What a hacker can actually do when they access a water system varies widely depending on the device they hack. There's also a huge variety in how the roughly 148,000 public drinking water systems in the US operate, including the about 50,000 systems that supply drinking water to residents year-round. "It really depends on the device and what that device is managing or controlling," Kevin Morley, federal relations manager for the American Water Works Association, told Business Insider. "It could be a pump, it could be a motor, and it could be something as simple as a tank-level log that just says the tank is full or not full." Some of the recent attacks have resulted in real-world impacts, such as loss of water pressure and flooding, according to the FBI, though the agency did not say where those incidents occurred. City officials in Braham, Minnesota, said a cyberattack shut down the controls for its well and water treatment plant, temporarily causing the city to rely on its water