In 90 percent of all cases, firefighters extinguish fires with water. The extinguishing water is taken from standpipes located on the street, known as surface and underground hydrants. To avoid damage to hydrants and prevent traffic disruptions, underground hydrants are predominantly used for firefighting water supplies today. Cities and municipalities are responsible for keeping hydrants clear so that the fire department is not "left on the hook." Therefore, the following generally applies: If hydrants are located on sidewalks and parking areas, hydrant covers and closures must be kept clear of motor vehicles. Hydrants on properties or adjacent sidewalks must be accessible at all times and kept clear of snow and ice. Special note: Vehicles parked on hydrants pose a major obstacle for firefighters. Valuable minutes are lost when frozen hydrants must first be made accessible and thawed by the fire department. Caution: The water supply of a tank fire engine is used up in just a few minutes.