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Water – How Much Do I Need while Overlanding?

Water – How Much Do I Need while Overlanding?


Don’t Take Chances With Water

Of all your supplies and kit, this is the one thing that will most quickly present a clear and present danger to your life if you do not get it right.

Overland Bound does not like to be dramatic about overlanding and the risks and challenges you will face because that makes it seem inaccessible and it’s not. We do however insist we present the information to overland safely, and that you are prepared for what you are doing. This is first on the list in terms of preparation.

It seems like a basic question, but there are a few things to consider when planning. Consider these guidelines and you will have the right amount of water on your journey, and that’s one less thing to worry about. Here are some things to consider. You can skip right to the end for a good rule of thumb!


I came up with a general rule of thumb while traveling through Baja and I figure that is a pretty good way to go. The environment is arid, with very little water supply. That means it’s a good estimate pretty much anywhere you travel. You need to bring all of your water with you, and the environment is trying to suck it out of your body. Also, depending on your rate of travel and your chosen route, overlanding can be exerting. Sure if you cruise the paved routes, you’re not going to break a sweat, but if your environment and route is off-road high pace travel through the sand, you’ll be tired. Will your route have water along the way? If so, you can carry less! We take less water when we travel through the Sierras, especially to places where we know there is a good water supply.


The weight of water is a serious consideration. A gallon weighs about eight (8) lbs. That adds up quickly if you are traveling for days or weeks. Multiply that by the number of people you have and your vehicle will be put to the task! That’s another reason planning water consumption is important. If you don’t have to carry it, don’t, but you have to be sure. You can carry less if you can process and filter water where you go. Which brings us to…


We use a MSR HyperFlow Microfilter for our traveling needs. It’s super small (7 x 3.5in), super light (7.4oz), and it pumps three liters per minute. It cleans protozoa, bacteria, particles, is field cleanable. If space is not a concern for you, there are larger units that are a bit easier to handle, and don’t require you to lower the mesh filter into the water source.


This is a huge topic and we’ll only touch on it lightly here. There are references below for more detail. Water can be contaminated a number of different ways. Is it biological or chemical? If it is chemically toxic water, just don’t drink it. filtration, and chemical treatment will not purify chemically toxic water.

For biologically contaminated water, there are two ways to treat it, boiling and chemical treatment.


Boiling is the most effective way of killing all microorganisms. According to the Wilderness Medical Society, water temperatures above 160 F (70 C) kill all pathogens within 30 minutes and above 185 F (85 C) within a few minutes. So in the time it takes for the water to reach the boiling point (212 F or 100 C) from 160 F (70 C), all pathogens will be killed, even at high altitude. At higher altitude, you want to boil water longer since water boils at a lower temperature.


There are two types of chemical treatment, iodine and chlorine.  Some people are allergic to iodine, especially those who are allergic to shellfish. You have to know if you or anyone in your party is allergic to iodine if you use that method! There are a number of products on the market and for both methods, those products will tell you how much you need. Follow the instructions. For chlorine, the colder the water, the less effective the treatment. After treatment, let the water sit for 30 minutes to allow purification to occur. For iodine, add 5 drops per quart for clear water, 10 drops for cloudy water. Again, follow the instructions and refer to our references below for more detail.

Iodine treatment is included in the Overland Bound Survival Kit manufactured by Fieldcraft.

So How Much Water Do I Need?

Here is the rule of thumb: You need two gallons per person per day. This water is for all needs including dishes and sponge baths (no 5 minute showers). That very complicated formula is as follows:

Camel Back Hydration Calculator

(number of people) x 2 x (number of days) = total water needed

Corrie and I require 20 gallons of water for a five day trip. This may seem like a lot, but remember, it is a conservative estimate and you don’t want to run out of water. This tested rule of thumb was verified by our friends of Live Work Wander during their recent trip through Baja. If you want to try a fun calculator, Camel Back provides a hydration calculator on their website!

Please don’t take risks when it comes to water. You can go many days without food, but without water, you’re in trouble fast, and that just takes the fun right out of overlanding!

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