How Much Water Should I Put in My Pack?

On one of my first backpacking trips, my friend Eric and I hiked in 5 miles and 1,000 vertical feet to a high country lake. On this trip, I packed over a gallon of water on my back to make sure I stayed hydrated. While I definitely didn’t go thirsty, I hardly drank any of my 32 oz Nalgene on our way to the destination, let alone touching either of the two 48 oz bottles in my backpack. When we got to the lake, the 50+ lbs pack was really starting to feel really heavy. I rifled through my stuff to identify ways to lose a little weight. That’s when I realized I had packed nearly 8 lbs more water than I needed. 

If you multiply 8 lbs times the number of steps taken in 5 miles of hiking, that’s over 80,000 lbs my legs lifted that they didn’t necessarily need to. To add insult to injury, our destination was a pristine high mountain lake with great water and I had plenty of water purification tabs plus a filter in my pack with me. To say I packed in too much water on my back is an understatement.

Since that trip, I have scaled back the amount of water in my pack significantly and relied much more on more frequent water fill-ups than packing too much water on my back. It takes time to hone in exactly how much water your body needs for a stretch of hiking where you may not have refilling opportunities. Not to mention, you need to budget water for meals and morning coffee at camp. 

Reflecting on this experience and thinking about all the times since that I haven’t packed enough leads me to the question, how much water should I carry on my back at any one given time? 

Determining Intake

First, I asked our resident backcountry dietitian, Kyle Kamp, what a person should expect to need for water while backpacking. He directed me to some guidelines from the American College of Sports Medicine. They recommend somewhere between 12-24 oz per hour.  This is about 1.5-3.7 gallons per day if you’re hiking while you’ve got daylight in the middle of summer (16 hours). Kyle broke it down further to make it a little easier to digest for folks and recommended a conservative 3-6 oz every 15 minutes. Keep in mind, everyone’s body is going to need a little bit different water intake, so don’t take this as gospel, but it is a good starting point. 

If that seems like a lot of water to take in, it’s because it is! But because that’s a guideline does not mean it’s the same for each person. It’s recommended to drink if you’re thirsty and not to put it off until the next “y” in the trail or ridgeline on the horizon. That said, it is important to make sure you do not feel like you’re forcing water down because too much water can result in dangerous electrolyte imbalances. 

It’s usually a safe bet to make sure you don’t drink so much water while you hike that you get a “sloshing” in your stomach. Your belly can only hold so much fluid anyway! Also, a good, albeit crude, field litmus test is just to make sure your urine maintains a straw yellow color. Not too dark, not too clear. 

Your body’s build and diet can greatly affect your hydration in the backcountry and should be considered, as well. So if you need someone to help you dial it in further, Kyle is a great resource with his Valley to Peak Nutrition practice. 

What does that look like?

Where does that leave me on my 5-mile backpacking hike to a high country lake? Assuming it took us 2 hours to get in there (moving at a pretty steady clip) I probably should have drunk all of my 32 oz Nalgene and filled the others with water for food and drinks when we arrived at the water source for the night. Knowing this would have saved me 6.26 lbs of weight in my pack at least. Probably more since I would not have even brought both large bottles in with me in the first place. 

In this case, packing 32 oz of water in my pack would have been sufficient. If you are headed out for 2 hours worth of hiking, the same can be said for you, plus or minus a few ounces for your individual needs. 

One thing that is being assumed is that you will have access to water for food and hot drinks while you are at camp. If you are camping for the night well away from water, be sure to fill up with what you need for your food. Your water needs for food varies from company to company and meal to meal. This is another good reason to test out your meals well before you enter the backcountry. For total camp needs, just be sure to keep your food needs in mind as you leave your last water stop for the day. 

When you look at your backcountry travel routes for the day time, it is crucial to map your mileage between known water and plan accordingly so you make sure you will both stay hydrated and to hydrate meals, but not be carrying too much excess in weight on your back. Of course, knowing your hiking pace and capabilities will come from personal experience, so when in doubt, it’s okay pack a little too much water. 

Conclusion

At the end of all this, how much water really should you put in your pack? Enough for you to stay hydrated. Not so much that you will have a half-gallon left in your pack at the next fill-up spot. 

Be diligent about your planning. The only way to determine your real water need is to know your pace, plan your water sources and when in doubt, don’t be afraid to carry a little extra.

The first full-time hire to the team, the author, Jaden Bales, was drawn to working for Backcountry Fuel Box as an avid outdoorsman and backpacker. Jaden spends 100+ days per year outside, whether it's shed hunting, backpacking, backcountry skiing, or chasing critters in hunting season. If you have any questions about this article or want to get a hold of Jaden specifically about the Backcountry Fuel Box, shoot him an email jaden@backcountryfuelbox.com