In order to be able to interpret the size of the freshwater tank it makes sense to understand the water consumption figures. When calculating these numbers you will soon discover the Bliss Mobil unit has sufficient fresh water capacity to provide several people for multiple days without the direct requirement for refilling fresh water.
The grey water tank is sized to store waste water from the kitchen and shower for several days. Also the black water tank is large enough to store the waste from the toilet for multiple days. By having enough capacity in both the fresh and waste water tanks, one can choose the right moment and spot to empty waste water.