Wheel Well Water Tanks Explained
Why Builders Use Them and How They Fit Into Real Van Layouts
Wheel well water tanks are one of the most common fresh water solutions in camper vans.
They are popular not because they are perfect, but because they solve several important problems at once. When used intentionally, wheel well tanks integrate cleanly into layouts, protect water in cold weather, and pair well with exterior tanks for balanced systems.
This guide explains what wheel well tanks are, why builders use them, and how they fit into complete water systems rather than standing alone.
What Is a Wheel Well Water Tank
A wheel well water tank is molded to sit over the factory wheel arch inside the van.
This area is difficult to use for storage or cabinetry, which makes it an efficient place to store water. The tank follows the curved shape of the wheel well and converts otherwise awkward space into usable capacity.
Because it sits inside the living area, it behaves like an interior tank rather than an exterior one.
Why Wheel Well Tanks Are Commonly Used for Fresh Water
Wheel well tanks stay within the insulated and heated envelope of the van, which greatly reduces freezing risk. Plumbing connections remain inside, which simplifies routing and service access.
For this reason, wheel well tanks are most often used as the primary fresh water tank.
Layout Constraints Are the Main Tradeoff
The main limitation of wheel well tanks is that they must fit within the layout.
They usually live inside a cabinet, bench, or galley, which means cabinetry must be designed around them. This can limit drawer depth or storage options if not planned early.
Wheel well tanks work best when the layout is designed with them in mind from the start.
Typical Wheel Well and Center Tank Sizes
Wheel well and center mounted tanks come in a range of sizes depending on layout.
A 36 gallon center tank is often used in larger layouts where maximum fresh water capacity is desired.
A 24 gallon center tank is common in tighter builds where preserving storage space matters more than total capacity.
Both sizes work well when paired with an exterior tank for gray water or supplemental storage.
Wheel Well Tanks Work Best as Part of a Combination System
Most professional builds do not rely on a single tank.
Wheel well tanks are typically paired with an undermount tank to balance interior space and system function. See our blog that explains undermount tanks.
Common combinations include:
36 gallon center fresh tank with a 28 gallon spare tire tank
20 gallon center fresh tank with a 22 gallon driver side undermount
These setups allow fresh water to stay protected while exterior tanks handle gray water or extra capacity.
Plumbing Advantages of Wheel Well Tanks
Wheel well tanks simplify plumbing. Because fittings are inside the van, there is no need to protect lines from road debris or exposure. Pumps, accumulators, and water heaters can be mounted nearby, which reduces noise and pressure loss.
This makes wheel well tanks especially friendly for first time builds. Check out our blog on plumbing your camper van.
Pumps and Accumulators Still Matter
Even though wheel well tanks are interior, they still rely on pumps. Fresh water must be pressurized to reach sinks and showers. Pumps and accumulators smooth flow and reduce noise.
This is standard practice and not a drawback, but it is an important part of the system.
Service Access Considerations
How a wheel well tank is mounted affects serviceability. Rigid straps create a very secure and permanent install. Soft straps or bracket systems may allow easier access to fittings if future service or changes are expected.
Builders choose mounting methods based on how often they expect to access the tank.
Winter Performance of Wheel Well Tanks
Wheel well tanks perform very well in cold climates.
As long as the cabin is heated, the tank remains above freezing. This is why four season builds in cold regions almost always place fresh water inside the van.
Winterization is still important when the van is stored without heat.
When Wheel Well Tanks Might Not Be Ideal
Wheel well tanks may not be ideal if:
- The layout has no available wheel well cabinetry
- Maximum interior storage is the top priority
- The van is used only in warm climates
In these cases, builders may rely more heavily on undermount tanks. Check out our blog that explains the differences between wheel well and undermount tanks.
Builder Perspective on Wheel Well Tanks
From a builder standpoint, wheel well tanks are a reliable foundation for fresh water systems.
They are not meant to solve every problem alone. They work best when paired with exterior tanks and designed into the layout intentionally.
This combination approach is why they remain so widely used.
Final Thoughts on Wheel Well Water Tanks
Wheel well water tanks are not just a convenient option.
They are a deliberate design choice that balances freezing protection, plumbing simplicity, and space efficiency. When combined thoughtfully with undermount tanks, they form the backbone of many of the best camper van water systems.
