Overland vehicles require a way to carry drinking water, preferably a minimum of 10 gallons, or more. Ideally, for International Overland Travel, they will also have a reliable way to filter and treat water to ensure purity and removal of bacteria when only water of questionable quality is available for refilling.
I designed and built a custom drinking water tank, pump, filtration and treatment system that Iíve mounted underneath my Jeep Wrangler Unlimited. Iím going to keep this DIY article generic enough so it can be applied to any 4x4 vehicle, not just the Wrangler. This is a very involved project, and shouldnít be taken lightly. At each step Iíll present the various options I considered, along with what I see as the pros and cons to each so you can design your own system to meet your needs. This article is mostly focused on how you will design your own system, rather than how to actually build it. Once youíve made all the hard design decisions and bought everything you need, everything else is mostly just connecting it all up however you can make it all fit in tight spaces!
No matter what options you choose, this project will require hundreds of dollars, and likely many days of work by the time itís all said and done. It might also require significant modifications to your vehicle, possibly permanently.
That being said, itís also one of the best modifications Iíve ever made. Heading off the beaten path and knowing I have a huge supply of safe drinking water at the turn of a tap is a wonderful thing.
1. Where to mount the tank
The biggest decision is where to mount the tank itself, either inside in the cabin somewhere, or underneath the frame rails somewhere.
- No drilling holes in anything to run hoses
- No need to make a rock guard/skid plate
- (Maybe) No need to worry about anything freezing, depending on how cold you plan to get and if youíll have the heater running
- You could also make the entire install removable without too much effort, so you could have it in for some weekend trips, and take it out for the weekdays.
- The tank will take up precious interior cargo volume, depending on your vehicle this could be a big problem
- The weight of the water will be higher which is bad in off road situations. If you do a lot of hard trails, think carefully on this point.
- Draining the tank could be difficult and/or messy
- The weight of the water is absolutely as low as possible.
- The tank doesnít take up any interior volume, which might also mean it can be bigger overall.
- You need a space be enough for it to fit.
- Depending on where you put it, the weight could be very far back (i.e. behind the rear axle)
- You will have to make a rock guard/skid plate, and even then the tank is vulnerable to damage.
- You might have to worry about it freezing.
I am very limited on interior cargo space on my build, so from the very beginning I wanted to mount the tank underneath. I wanted as much water storage as I could physically fit in the space available, because that will likely be the limiting factor of how many days I can go without being back in a town for the trip I have planned.
On the Wrangler JK Unlimited I relocated the Evaporative Canister further back (using a kit), opening up a large space between the exhaust and the driveshaft on the drivers side.
I like this location as the weight is very low, and is almost centred between the two axles.
It would have also been possible to relocate the muffler into that space, and mount the water tank where the muffler normally sits behind the rear axle. A tank of similar size would fit there, though I didnít choose this route because I didnít want the weight that far back, and modifying the exhaust was more expensive than moving the Evap Canister.
2. Custom made tank or generic?
It all comes down to price. Custom made tanks can be made to any size, meaning youíll get the maximum possible amount of water storage for the space you have available. Be warned, custom tanks are around the $500 mark, where-as generic RV or Boat drinking water tanks can be had for $50-$150.
Either way, be certain your tank is drinking water safe!
3. Plastic or Stainless Steel Tank?
Plastic is lighter, stainless is more durable. If you go with stainless make sure you read up on what is appropriate to clean the tank with to ensure nothing bad builds up in the tank.
I personally chose plastic because itís lighter and I found the size I needed.
4. Do you require filtration and/or treatment?:
For a vehicle staying in North America, Iím not sure I could justify the extra expense and complexity of a filtration system. 99.9% of all tap water is perfectly drinkable, as-is water from lots of mountain streams. When in doubt Iíd add a teaspoon of chlorine to each fill up and call it good.
Given Iím going to Africa for 2 years, I wanted to have extremely high quality filtration to add an extra safety margin when filling up from water that is supposed to be ďgoodĒ, with no guarantees.
You can never be too careful.
After experiencing water in Central and South America for two years on the road, I would personally run very good filtration and treatment for that trip too.
5. Do you require a pump?
Given the pump is cheap, and the convenience of having running water, Iím going to go ahead and say you do want a pump. Trust me, you wonít regret it. Getting water out of the tank with a hand or foot pump is certainly possible, though I never looked into it personally.
6. How do you want to fill the tank?:
There are a few different options here, that likely depend on where your tank is mounted, if youíre running filtration, and if you want to cut big holes in your vehicle.
You could just have a large diameter hose with a fill spout you physically pour water into, like older RVs. It would be your choice if the spout was inside the vehicle, or mounted to the outside with a locking cap like those older RVs. Mounting it outside might require some big holes to be cut, and Iíd personally want a locking cap on it if I went that route.
Suction using the pump
If youíre running filtration, itís likely you want to filter the water before it goes into the tank. I designed my system so that water is sucked in a suction hose, through the pump, through the filter and UV treatment, then into the tank.
On the way out of the tank it goes from the tank, through the pump, through the filter and UV treatment and finally out a faucet for use. This system is working well so far.
7. How do you want to use water coming out of the tank?:
I personally have a regular faucet mounted in my Jeep, and Iíve also seen Overlanders that have a spray nozzle on the end of a flexible hose so they can spray thing outside their vehicle. Both have their uses, and I might wind up running both so I can choose which to use for what purpose.
8. Do you want a depth gauge?:
There isnít much point having a tank if you donít know how much water is in there. If the tank is inside and clear enough, you might be able to see it to estimate how full it is. If the tank is underneath, itís going to be very hard to know how much water you have without a gauge of some kind.
Hopefully you are starting to get a picture in your head of what you want your water system to include, and how it will function. Read on to see how I made mine, which will likely further help clarify your design.