Water & Weight

Water is the driving force of all nature.
Leonardo da Vinci

It is easy to take water for granted, but having the ability to carry a sufficient amount of water in an expedition vehicle is the single biggest factor in the ability to camp remotely for extended periods of time and be comfortable. So why doesn’t every expedition vehicle have a large water tank? Primarily because water is heavy and many smaller expedition vehicles have a limited cargo carrying capacity (CCC). With one gallon of water weighing 8.35 pounds, smaller 10–20 gallon  (84–177 pound) tanks are feasible, but as soon as the tank size is increased to a meaningful 85 gallons or more, the weight of the water quickly exceeds the carrying capability of smaller vehicles.

Water Requirements

Water needs in an expedition vehicle includes drinking, cooking, washing, showering and toilet flushing. At an absolute minimum, a person could carry just enough water for drinking. Depending on factors including amount of exercise, temperature, altitude, humidity, weight and sun intensity, a single person typically requires .5–1.0 gallons of water per day to stay healthy. Many smaller “expedition vehicles” have water tanks as small as 10–20 gallons which means that a couple using water only for drinking would have a 10–40 day supply, which is probably more than long enough for a couple that is not showering!

At 8.35 pounds per gallon for water, carrying the 10–20 gallon  bare minimum amount of water required to stay alive is easily accomplished with almost any vehicle. But what happens when cooking, washing dishes, and showering are added into the equation? Cooking and washing dishes can be easily accomplished with 1–4 gallons per day, but a typical 5 minute home shower uses 7–8 gallons and conservation minded camper could probably make do with as little as a 1 gallon shower. Toilet flushing is variable, but .25–.5 gallons should be enough for a typical flush. 


Estimated Water Use (gallons per day)


(Assumes two people camping)


Ultra Conservative

Typical Use

Luxury Camping






















Days Until Empty

Tank Size (Gallons)

Ultra Conservative

Typical Use

Luxury Camping













The conclusion that can be drawn is that to camp with a reasonable amount of comfort requires a substantial amount of water which is why the standard water capacity of an EarthRoamer XV-LT is 85 gallons.

Water Capacity

So how much water can safely be carried without overloading the vehicle? Obviously it depends on the vehicle but let’s do a quick comparison a of Toyota Land Cruiser (a vehicle commonly touted as being a good base vehicle for an expedition vehicle) and a Ford F-550 cab chassis truck (the EarthRoamer XV-LT base vehicle).

2011 Toyota Land Cruiser   % of GVWR % of Curb Weight
Gross Vehicle Weight Rating (GVWR in lbs.) 7,275    
Curb Weight (lbs.) 5,765 79%  
Cargo Carrying Capacity (CCC in lbs.) 1,510 21% 26%
Water Tank Size (Gallons)  10 20 85
Water Weight (lbs.) 84 167 710
Water weight as a percent of CCC 5.5% 11.1% 47.0%
Remaining CCC (lbs.) 1,427 1,343 800
2011 Ford F-550 Crew Cab   % of GVWR % of Curb Weight
Gross Vehicle Weight Rating (GVWR in lbs.) 19,500    
Curb Weight (lbs.) 8,585 44%  
Cargo Carrying Capacity (CCC in lbs.) 10,915 56% 127%
Water Tank Size (Gallons)  10 20 85
Water Weight (lbs.) 84 167 710
Water weight as a percent of CCC 0.8% 1.5% 6.5%
Remaining CCC (lbs.) 10,832 10,748 10,205

A Land Cruiser with a 20 gallon water tank has used over 11% of its cargo carrying capacity (CCC) just to carry a minimal amount of water. An 85 gallon water tank installed on a Land Cruiser would use 47% (almost half) of its carrying capacity with water alone and only have 800 pounds of cargo carrying capacity left for people, gear and installed accessories. This is obviously not feasible. By comparison, an 85 gallon water tank installed on an F-550 only uses 6.5% of its CCC.

So why did we choose a Ford F-550 as the base vehicle for the EarthRoamer XV-LT? There are many reasons, but it should be obvious that the massive cargo carrying capacity of the F-550 was one of the major reasons. The Land Cruiser can only carry 26% of its own weight, but the F-550 can carry an incredible 127% of its own weight! The F-550 is a commercial duty truck engineered and built to carry heavy loads which makes it the perfect foundation for a serious Xpedition Vehicle.

   Toyota   Ford  Ford vs. Toyota

Compared to the Land Cruiser,
the Ford F-550

Curb Weight 5,765 8,585 49% Weighs about 50% more than
the Land Cruiser…
Cargo Carrying Capacity 1,510 10,915 7.2 …but has more than 7 times
the carrying capacity
Estimated MPG City 11 9 -18% Gets 18% lower fuel economy
in the city
Estimated MPG Highway 18 12 -33% and 33 % lower mileage
on the highway
Fuel Capacity Gasoline Diesel    
Fuel Capacity 25 90 3.7 But carries 3.7 times as
much fuel…
Weight (lbs./gallon) 6.1 7.0    
Fuel Weight 149 630    
City Range (Miles) 271 810 2.9 … and has almost triple
the  city range.
Highway Range (Miles) 443 1,080 2.4  … and has over double
the  highway range.

The point of all of this is not to pick on Land Cruisers, in fact we think they are fantastic vehicles. The point is to illustrate that a serious Xpedition Vehicle needs to be able to carry a significant amount of weight and carrying a sufficient amount of water is not a trivial task. Water is heavy!  Many smaller vehicles, simply aren’t up to the challenge, they simply don’t have the carrying capacity to carry enough water and gear for a serious expedition camper. We researched the GVWRs and CCCs of many vehicles including Land Rovers, vans, light trucks, half-ton trucks and one-ton trucks, and invariably the Ford F-550 is the superior choice for hauling heavy loads.