Hospital water supply system includes: air conditioning systems, dialysis equipment, drinking equipment, Minsheng water, clean water, etc., the use of programmable logic controller (Programmable logic controller, called PLC) combine graphical control system, effective management and control related to water resources the equipment operation, understanding water resource inventory; and links with the hospital's early warning system performance human-machine interface, and the prevention of critical situation occurs, reduce human error, saving manpower and time, it can occur the first time warning, notification administrations and public works personnel, via the Internet, by a remote system using the device, direct connection to the monitor HMI, view the equipment situation, we can understand the point of failure to promptly remove the cause of a system failure, to ensure the proper functioning of the systems hospital and patient safety, for the purpose of the case study.