How much water needs to wash a car?

To clean a four-doors saloon we normally use 4-5 litres of water, depending on the operators’ skill and experience and how dirty the car is. Also, the climate has great affect on the water consumption. The dryer and hotter the weather is it consumes more water as more water content of the steam evaporates in the atmosphere before getting in contact with the car surface. Still, it is a small amount of water consumed comparing to the conventional car washes that can waste hundreds of litres of water to wash a car.