Fire hydrants

A fire hydrant is a water supply point for firefighting purposes. It is a connection to a water source, typically a municipal water supply, and is used by firefighters to access water quickly in the event of a fire.

Most fire hydrants fit within two categories, wet and dry barrel. As the name implies, dry barrel hydrants are free of water until its valve is opened. These hydrants are designed prevent issues caused by freezing water inside of the barrel. The main reasons for the USA having above ground hydrants is for faster location, particularly when snow has fallen, and the large diameter pipework allows much higher flowrates - needed in the USA because of the much greater use of timber construction in houses.