We have LOTS of tanks for diesel and water.
For diesel we have the standard Mitsi 135 litre diesel tank and a reserve diesel tank built to fit around the step and spring hanger with one end forming part of a wheel arch.
Two aluminium tanks with a total capacity of around 350 litres are for general use water and fit snugly inside the chassis rails.
The step tank holds around 140 litres and occupies otherwise wasted space.
Drinking water is kept seperate from general use water and is stored in two tanks.
The floor of the bathroom is raised so that a robust 180 litre plastic tank fits under it.
A poly water tank is squeezed into a small space created by re-aligning the exhaust and that tank holds 40 litres of drinking water.
The grey water tank holds around 180 litres and fits snugly between the main framing of the motorhome base.
We have quite a bit of storage for jerry cans of fuel and water and will be carrying fuel for the chainsaw, gennie etc. With the black water of the compost toilet and 26 lites of hot water in the gas hot water system we will have a lot of weight just in the various liquids.