A fire hydrant or firecock is a connection point by which firefighters can tap into a water supply. It is a component of active fire protection. Underground fire hydrants.

Before piped mains supplies, water for firefighting had to be kept in buckets and cauldrons ready for use by 'bucket-brigades' or brought with a horse-drawn fire-pump. as wooden mains water systems were installed, firefighters would dig down the pipes and drill a hole for water to fill a “wet well” for the buckets or pumps.