A hydrant (short for fire hydrant) is a sturdy metal pipe that sticks up from the ground along city streets, providing firefighters with instant access to a powerful water supply. When a building catches fire, firefighters connect their thick hoses to the hydrant, open a valve, and water rushes out with enough force to shoot high into the air and douse flames from a distance.

Cities install hydrants every few blocks so firefighters can quickly reach water wherever a fire breaks out. The water comes from underground pipes called water mains that run beneath streets, carrying water throughout the city. Without hydrants, firefighters would need to carry all their water in trucks, which wouldn't be nearly enough for a serious fire.

You've probably seen hydrants painted bright colors, often red or yellow, so they're easy to spot in an emergency. Some cities paint them different colors to show how much water pressure they provide. Dogs famously like to mark hydrants as they walk by, and in summer, firefighters sometimes open hydrants slightly to create fountains where kids can cool off on hot days. But the hydrant's real job is serious: it's a piece of emergency equipment that helps save lives and property when every second counts.