Programmable logic controllers, commonly dubbed PLCs, are small computers used to operate pumps, valves and other equipment inside water facilities. The remarks come about a week after CISA warned that hackers were increasingly targeting internet-connected controllers used by water and wastewater utilities. More than 30 community water systems in Minnesota were targeted late last month, according to state officials. CISA also tries to identify vulnerable organizations before they are attacked by examining the broader collection of internet-facing systems, Andersen said. Water utilities can be difficult to secure because many are small, have limited budgets and depend on aging equipment installed and maintained by multiple contractors.