It is generally believed that as long as the fire truck arrives at the fire site, it can immediately go out of the water to put out the fire. In fact, quite a few of the fire trucks equipped by the fire brigade do not carry water, such as elevating fire trucks, emergency rescue vehicles, fire lighting vehicles, etc. They must be used together with fire fighting vehicles. However, some fire fighting vehicles are also in urgent need of finding water when fighting fire because of their limited carrying capacity. At this time, the fire hydrant will play a huge role in water supply.