The Prier C-634 & C-636 provides a year round source of water to areas of structures that are subject to freezing temperatures. The hydrant valve is connected to the supply piping in the heated portion of the structure, eliminating the possibility of freezing. To assure freeze protection, the hydrant will drain even with the hose attached & under pressure. The integral vacuum breaker/backflow preventer provides protection against cross-connection with the potable water system, utilizing a check valve to prevent back pressure & a vacuum breaker to vent in the case of siphonage. A removable operating key is provided to prevent unauthorized usage of the hydrant. No special installation tools are required.