Sprinter & Transit Water Tank Guide: Wheel-Well vs. Under-Chassis Sizing (11, 20, & 24-Gallon Options)
Water planning on the road is an exercise in ruthless spatial efficiency. Water weighs 8.34 lbs per gallon (1 kg per liter). How and where you store liquid ballast dictates not only how long you stay off-grid, but how your van handles at 70 mph.
At Nomad Vanz, we reject awkward rectangular tanks strapped inside living areas. Instead, builders choose between two premier routing architectures: Interior Wheel-Well Enclosures that claim dead factory body cavities, or Under-Chassis Framemount Tanks that keep your floor plan completely open.
Water Tank Architecture: Wheel-Well vs. Under-Van Chassis
| System Category | Capacity & Key Models | Chassis & Placement | Best For |
|---|---|---|---|
| Wheel-Well Enclosure | 11 Gal, 20 Gal, or 24 Gal (North West Conversions / Agile Off Road) | Wraps around rear driver/passenger wheel arches inside garage space | Multi-day off-grid camping, cold-weather protection, maximized interior safety |
| Under-Chassis Frame Mount | 11 Gal or 20 Gal Under-Van Units | Slung beneath the floor frame rail / step cutout | Keeping interior floorplans 100% open for living space and custom cabinetry |
Breaking Down the Options: Wheel-Well vs. Under-Mount
1. Wheel-Well Tanks (11-Gallon, 20-Gallon, & 24-Gallon):
These BPA-free, food-grade polyethylene tanks are custom-molded to fit the empty voids directly above your rear tires.
- The compact 11-gallon wheel-well tank is perfect for minimalist weekend setups.
- The 20-gallon driver-side tank (46”L x 9.5”H x 12.5”W) provides balanced high-volume capacity.
- The heavy-duty 24-gallon North West Conversions / Agile Off Road tank (48”L x 14”W x 16”H) maximizes every square inch of dead space around the arch. Because they sit inside the insulated thermal envelope of the van, they are much less prone to freezing during shoulder-season alpine trips.
2. Under-Chassis Framemount Tanks (11-Gallon & 20-Gallon):
If you want to preserve every inch of interior garage storage, undermount systems are the gold standard.
- The 11-gallon under-van tank mounts securely between the main frame and the passenger-side slider door step cutout using stainless steel brackets.
- The 20-gallon under-van tank uses rugged stainless steel mounting brackets and 3/8" rivnuts anchored to factory frame locations.
Key Takeaways for Your Layout
Choose interior wheel-well tanks if you frequently camp in sub-zero winter environments where under-van lines risk freezing solid. Choose under-chassis mount tanks if you are designing an open floor plan with custom pull-out pantries, internal showers, or extensive gear storage garages.
Explore our full lineup of Water Tanks and Accessories in the Nomad Vanz Store.
