A fire hydrant is a pipe that allows water to flow from a water main with the control of a valve in order to put out a fire. Above-ground fire hydrants originated in the 1800s, but the underground fire hydrant was used in Asia and Europe as far back as the 1700s. In the United States, a fire hydrant may also be called a “fire plug” or a “Johnny pump,” depending on the region.
Before the invention of the fire hydrant, firefighters used the bucket brigade or hand pumping systems, of getting water to put out fires. A hole had to be dug in order to retrieve water from the water main and firefighters would pass buckets of water from the hole along a line of firefighters to help get water to the fire. Since the newly dug holes had to be plugged up after the fire call, the term “fire plugs” began to be used.
A firefighter connects a fire hose to the fire hydrant and releases a valve to get water from the water main. The different valves on a fire hydrant allow it to be attached to different water sources that may be either pressurized or not pressurized. Most fire hydrants are designed to allow not less that 250 gallons (950 liters) of water to flow through the hydrant per minute.