A hydrant is an outlet from a fluid main often consisting of an upright pipe with a valve attached, from which fluid (e.g. water or fuel) can be tapped.
Depending on the fluid involved, the term may refer to:
* Fire hydrant for firefighting water supply
* Flushing hydrant for cleaning water mains
* Hydrant network systems used to transport aviation fuel from an oil depot to an airport, to fuel aircraft
* Snowmaking hydrants, which use water and air
* Standpipe (street), a type of domestic or neighbourhood hydrant for dispensing water when supply is interrupted or absent