In one embodiment, the disclosed apparatus is a process cooling-water isolation system used in a process tool. The system includes an isolation valve coupled between a water supply and an inlet of one or more components in a process-module water-cooling circuit. An open device allows cooling water to flow to the one or more components, while a close device prevents cooling water from flowing to the one or more components. At least one water-leak sensor is coupled to the close device to detect a water leak within the process tool. A check valve having an inlet port is coupled to an outlet of the one or more components, and an outlet port is coupled to a water-return reservoir. The check valve prevents water from back-flowing from the water-return reservoir into the one or more components. Other apparatuses and methods are disclosed.