hydrant

A hydrant is a connection point in a water distribution system that provides access to a ready supply of water. The term is most often associated with fire hydrants, public fixtures that let firefighters attach hoses to the municipal water main to obtain a pressurized water source for firefighting. Hydrants are typically located along streets and in public areas and connect to underground mains through a valve and stem mechanism.

Construction and components: A hydrant body is usually made of cast or ductile iron and includes a barrel, bonnet, valve, stem, and multiple outlets. Common outlet sizes are 2.5 inches or 4 inches, designed to fit standard fire hoses and adapters. A drain or bleed valve allow water to escape when the hydrant is closed, helping to prevent freezing in winter and ensuring the main remains pressurized when not in use. Hydrants are categorized as wet-barrel or dry-barrel types. Wet-barrel hydrants keep water in the barrel year-round and deliver water promptly when opened. Dry-barrel hydrants have an empty barrel that fills only when the supply valve is opened, with water draining from the barrel after closure to prevent freezing.

Operation and maintenance: Firefighters use a hydrant wrench to open or close the valve. Regular inspection ensures valves seal properly, outlets are clear, caps are secure, and the hydrant is painted and free of leaks. Color coding and markings may indicate ownership, flow capacity, or municipal specifications.

Other uses: In some contexts, hydrants provide temporary water access for construction, testing, or flushing of water mains, though their primary role remains firefighting.