Wheel Well Water Tanks
Wheel-well water tanks are the highest-capacity way to carry water in a van without giving up living space. The tank is moulded to wrap the inner wheel arch, so it occupies the dead volume behind the wheel that would otherwise become a hollow bench.
Fitments are sold by side and position: left and right tanks sit outboard of the arch, and centre tanks span the space between them under a bed platform. Dually vans get a dedicated slim profile because the outer wheel eats the outboard clearance.
Weight distribution matters: water is 8.3 lb per gallon, so a 33-gallon tank is roughly 275 lb sitting over the rear axle. Split left and right if you can. See all mounting styles in Van Water Tanks, or go straight to undercarriage tanks to keep the interior completely clear.
