The hacking of a municipal water authority in a small Pennsylvania town is prompting new warnings from U.S. security officials as states and the federal government are wrestling with how to harden water utilities against hackers. Officials say the danger is hackers gaining control of automated equipment to shut down pumps that supply drinking water or contaminate drinking water by reprogramming automated chemical treatments. The efforts took on new urgency in 2021 when the federal government’s leading cybersecurity agency reported five attacks on water authorities over two years, four of them by ransomware and a fifth by a former employee. Potentially hostile geopolitical rivals such as Iran and China are viewed by U.S. officials as a threat.