If you’ve ever run out of water on a hike, you’re not alone, and you know how scary it can be to face miles or hours without a sip.
In December 2014, I set out to hike the California Riding & Hiking Trail in Joshua Tree from Blackrock Canyon to Juniper Flats and back. The 36 mile out and back overnight trip would be my first solo backpacking adventure, and my first time hiking in Joshua Tree.
That trip taught me many valuable lessons, one of which was the importance of estimating and managing my water consumption properly on a long hike. Although I didn’t run out of water, a series of mistakes led to me becoming dangerously dehydrated.
If you’re uncertain about how much water you should carry on a hike or find yourself running dry more often than not, keep reading. This article will help you identify important things to consider before your hike to avoid dehydration on the trail.

Establishing Your Baseline
To get a good baseline for your pace and water use, you should be tracking the following three things, at a minimum, every time you go hiking:
- Total distance hiked
- Time it took to complete the hike
- Amount of water you drank
The longer you track this information, the more accurate your water needs estimates for future hikes will be. After tracking my hikes for more than three years, I know that I hike between 3 and 3.5 mph and drink about ½ liter of water per hour on average. Based on this information, I know I need to drink about 1 liter of water on an average 6-mile hike.
Everyone is different, so it is important that you track your hikes so that you can estimate your water needs accurately for yourself. Also, it’s important to keep in mind that this is only a baseline average to be used for estimating. Other things, like weather and the difficulty of a hike, need to be considered as well.
Track Your Hiking Distance and Time
To establish your hiking pace, you need to know how far you hiked and how long it took you to complete that hike. I track all my hikes, either on my phone using and app like Runkeeper or on a GPS device. Any running or fitness app will do as long as it gives you accurate results.
Track Your Water Use
At the beginning of every hike, you should know exactly how much water you are carrying when you hit the trail. When the hike is over, make a note of how much water you have left over, if any. The difference between what you started with and what you have left over, is the amount of water you used on your hike.

Adjust for Trail and Weather Conditions
Now that you know how much water you will drink on an average hike, it’s time to start thinking about other factors that can affect how much water you will need to carry on a particular hike.
In general, you should take more water if the hike will be:
- More difficult than usual (more sweat, effort and/or time)
- Hotter than usual
- Drier than usual
Conversely, you may be able to get away with taking slightly less water if the hike will be:
- Easier than usual
- Cooler than usual
- More humid than usual
It’s important to adjust your water estimates according to the environment you are hiking in. Factors like temperature and humidity affect how much water you need, so always be prepared and bring extra water if you are inexperienced in a specific environment.
When it comes to water, always err on the side of safety.

Refilling on Longer Hikes and Backpacking Trips
Plan ahead to refill your water supply if you won’t be able to carry enough for your hike.
Natural Water Sources
Many times you will be able to refill your water supply using natural water sources in the environment. Lakes, rivers, streams, creeks, and even a small trickle coming from the rocks can all serve as the perfect spot to fill up.
I’m not going to get into filtering or treating water here. That’s a complex (and somewhat controversial) topic all its own. What I will say is that it’s always important to know that the water you’re drinking is free of harmful viruses and bacteria before drinking it.
Many major natural water sources can be found by simply looking at a high quality topo map. Some may be year-round, while others may be seasonal, so it’s important to know which is which if you’re going to be hiking off-season.
It’s a good idea to call the ranger station before your hike to double-check on water sources, as they may be dry due to drought conditions. Rangers are always happy to provide information on water availability to ensure hikers stay safe and hydrated.
Man-made Water Sources
Many parks, such as the Grand Canyon, provide water taps throughout the park near campgrounds and trails. Topo maps and maps from the visitors center typically show the location of these water sources.
Just as with your natural sources, it’s always best to check with the ranger station ahead of time to make sure the taps are in working order. Often they will be seasonal and only turned on during peak times of the year. And, just like the pipes in your house, they are subject to leaks, including catastrophic failures, resulting in emergency shut-downs.
Be safe and call ahead.
Water Caching
Some parks permit water caching, which is especially useful in areas like Joshua Tree that have limited man-made and no natural water sources. To cache water, find a hidden spot near the trail before starting your hike to leave some water for yourself. Water caching allows you to carry less weight and extend your hike as long as you desire. It’s important to note that rules regarding water caching differ between parks, and not all parks allow it, so be sure to call the ranger station beforehand to confirm.

A Few Final Tips
- Load up on water at your car before you leave
- Leave extra water in your car for when you get back, in case you run out on the hike
- Drink water at your refill stops to minimize the amount you need to carry to the next stop
- Remember your cooking and hygiene needs when estimating water for a backpacking trip
Be safe. Stay hydrated.
Title photo by: John Graham (IG: @adventuregraham)
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