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How Much Water Should You Carry When Hiking?

Staying Hydrated on the Trail

New hikers have a ton of common questions, but one of the most frequent deals with hydration. Specifically, they want to know how much water should you pack per person when hiking?

Carrying too much means lugging around excess weight, which is something we all want to avoid. But that’s likely better than the alternative – if you fail to bring enough, you’ll end up parched and miserable while making your way back to the trailhead.

Fortunately, there’s a pretty simple rule of thumb you can follow:

In most cases, you will find that packing ½ liter of water for each hour of hiking will keep you well hydrated.

Of course, there are plenty of exceptions, caveats and further considerations, but this time-tested guideline provides a great starting point. We’ll talk about some of the other things you’ll want to think about – and share some general hiking hydration tips – below.  

How Much Water Should You Pack Per Person When Hiking?

how much water to bring hiking

There are a few different ways to think about the general guideline provided above, depending on the units you’re most comfortable with and the numbers that are easiest to get your head wrapped around.

  • ½ liter of water for every 1 hour of hiking
  • 1 liter of water for every 2 hours of hiking
  • About 16 ounces for every 1 hour of hiking
  • About 32 ounces for every 2 hours of hiking
  • About 2 cups of water for every 1 hour of hiking
  • About 1 pint of water for every 1 hour of hiking

Personally, I prefer the 1-liter-per-two-hours version, but YMMV. Just try to commit the one you find most helpful to memory.

Of course, there’s another way to think about the amount of water you need to bring while hiking – you can think about the amount of water you’ll need for a given distance.

This ratio will involve a little more wiggle room, as different hikers trek at different paces.

That said, most people will end up hiking about 2 to 3 miles per hour in the backcountry. Just note that you’ll end up hiking slower as the difficulty (whether in terms of terrain, incline, or weather) rises.

If you’re in great shape, carry a minimal pack, and stick to flat trails, you may rack up 3 full miles an hour. But if you’re out of shape, lugging a heavy pack, or tackling a steep grade, you may struggle to complete 2 miles per hour.

Nevertheless, this means you’ll want to bring about ½ liter for every 2 to 3 miles you intend to hike. Or, if you’d prefer round numbers, figure approximately 1 liter per 5 miles.

How Much Water to Bring Hiking: Exceptions and Complications

hiking in deserts requires more water

Remember: The 1-liter-per-2-hours rule-of-thumb is just that – a guideline. You have to consider a variety of other factors when determining the ideal amount of water to bring.

Consider, for example, the following:

  • How hot is it? The higher the temperatures, the more water you’ll need to replace that which you lose by sweating.
  • How sunny is it? All other things being equal, you’ll need more water while hiking in strong sunshine than you will overcast or rainy weather.
  • How humid is it? If the humidity is very low, you’ll lose more water by breathing. Accordingly, you’ll want to increase the amount of water you bring to offset these losses.
  • How windy is it? Just like low relative humidity, strong winds will cause you to lose water more rapidly via breathing, thereby forcing you to carry a little extra. This is especially true if the air is also dry.
  • How accessible is water on the trail? If you’re hiking in a suburban park with plenty of water fountains around, you can decrease the amount of water you carry. The same could be said of backpackers who’re carrying water filtration equipment (provided that you’ll encounter plenty of water sources during the hike). But if water is going to be scarce, you’ll need to carry more.
  • Are you carrying snacks with a lot of water? While most hikers lean toward low-water snacks in the name of saving weight, some of us like to bring berries and fruit. These things contain quite a bit of water, which will help reduce your drinking water needs slightly.
  • Do you need water for anything besides drinking? Are you planning on cooking up a trail-side meal during your hike? Do you want to have some water for rinsing your hands? Do you need water for a cooling towel?

There’s one last thing to think about: How much water do you like to drink?

We all have varying water needs. Personally, I tend to chug tons of water. I may drink twice the general 1-liter-per-2-hour guideline at times. I don’t need this much, but I like drinking that much. It just keeps my spirits up and body feeling stronger.

But other hikers just don’t drink a ton of water, so they can cut back on the amount they carry without feeling thirsty on the trail.

Just make sure that you keep your own habits, desires and needs in mind when deciding how much water to bring hiking.  

Old vs Current Advice: How Much Water Do You Need Per Day?

We all remember the old water-drinking guidelines: You need to consume eight 8-ounce glasses of water per day. That’s 64 ounces a day – roughly half a gallon.

No one even seems to know exactly who first established this guideline, but it showed up everywhere. It was taught in health classes, made frequent appearances in after school specials and was plastered on posters. And this wasn’t a mere recommendation, either – it was treated very seriously. Drink your eight glasses a day or you’ll surely shrivel up and die.

But opinions have changed, and medical professionals no longer stick to rigid guidelines like this anymore. Some need more than this, but others need less.

Accordingly, the advice has become drink when you’re thirsty. That’s it (save for older individuals, who may have slightly less efficient thirst mechanisms).

And if you’re curious, the CDC has studied the amount of water people tend to drink. For adults, the average is 44 ounces per day.

General Hiking Hydration Tips

hiking hydration tips

Bringing enough water while hiking is certainly important, but it isn’t the only thing you’ll want to think about. Try to keep these other hiking hydration tips in mind the next time you hit the trail:

  • Try to drink small amounts of water frequently. Going long periods of time without water and then chugging a huge amount can leave you feeling bloated and gross. So, to the extent possible, try to sip on your water throughout the duration of your hike.
  • Increase your water intake at high altitude. As you climb higher, your body will lose water more quickly. So, try to drink even more water than you normally would if you’re hiking at elevation.
  • Wear sunscreen. You’ll start losing even more water per unit of time if you suffer a sunburn. So, slather on the sunscreen before heading out – particularly if you’re hiking in a sunny location at midday.
  • Make sure to drink water in cold weather. Many of us fail to drink as much water as we should while hiking in cold weather. But you can still become dehydrated while hiking in the winter, so keep on sipping.
  • Don’t forget about electrolytes. Sweating over a long period of time will leave you deficient in electrolytes, so make sure to consume snacks high in sodium, potassium, calcium and magnesium while hiking. Nuts are great for this, but electrolyte replacement tablets can also be helpful.

Dehydration: Signs & Symptoms to Watch for While Hiking

dehydration symptoms

It is critical that you learn to recognize the signs of dehydration while hiking, so that you can address the issue and prevent serious problems.

Cleveland Clinic lists the following as signs of dehydration in adults:

  • Headache
  • Delirium
  • Confusion
  • Fatigue
  • Dizziness
  • Dry mouth
  • Dry cough
  • Rapid heart rate
  • Loss of appetite
  • Swollen feet
  • Flushed skin
  • Chills
  • Dark-colored urine
  • Constipation

Kids may exhibit additional signs of dehydration, including:

  • Deep, rapid breathing
  • Dry tongue and lips
  • Crying without producing tears
  • Dry, wrinkled skin
  • Sunken eyes

Neither of these lists should be considered exhaustive, but they include some of the most common signs and symptoms of dehydration. But additionally, you should consider your subjective feelings – if you feel dehydrated, you probably are.

What Should You Do If You Become Dehydrated While Hiking

addressing dehydration

Recognizing that you’re dehydrated is important, but it’s also critical that you know what to do if you start noting the signs and symptoms of dehydration.

For starters, you’ll want to stop hiking.

Sit down in a cool, shady place and break out that water bottle.

Start drinking slowly – you can’t rehydrate in a few minutes; it’ll take time for the water to work its way through your body tissues. You may want to use a cooling towel (or simply wet a T-shirt) to help cool off your skin too.

Consider using an electrolyte replacement or having a snack while you rest.

Over time, you should start feeling better. Once your symptoms ease, you can head back to the car or continue hiking.

Just make sure that you feel better before doing so. If your symptoms worsen or fail to improve after drinking water, call 911 or activate your emergency plan.  

How Much Water Should You Pack When Hiking: FAQ

questions about bringing water hiking

Hiking hydration questions are pretty common, so we’ve tried to put together a few of the most frequent queries we hear on the trail and from readers. We’ve covered a few of them above, but we’re putting them here too for convenience:

How much water should you carry while hiking?

Generally, most hikers will find that ½ liter per hour on the trail is sufficient. However, every hiker and situation is different, so this should only represent a starting point.

How much water should you drink on a 4-hour hike?

Using the ½-liter-per-hour guideline, you’ll want to bring 2 liters of water for a four-hour hike.

How much water should I pack per person?

Most hiking water guidelines are for each hiker. Accordingly, you’ll want to pack ½ liter of water per person for every hour of hiking.

How do you pack water for a long hike?

There are several different ways to pack water for a long hike, but most hikers opt for hard-sided plastic bottles or hydration bladders. Both approaches present different pros and cons, which we’ve laid out in our article about carrying water while hiking.

How do thru hikers get water?

There are two basic ways to replenish your water supplies while thru hiking; Filling your water bottle (or hydration pack) via municipal sources or by collecting and treating water found in rivers, streams, or other natural sources. The former approach is not always feasible, so most thru hikers opt to bring water treatment supplies and simply collect water as they go.

How do you hydrate before a big hike?

Typically, all you need to do is drink adequate amounts of water in the days preceding your hike. Herculean water-drinking efforts are rarely necessary for recreational hikers.  


Packing enough water while hiking is crucial for both safety and enjoyment, yet carrying too much can leave you struggling under all that excess weight.

The 1-liter-per-2-hour guideline is a good starting point, but don’t hesitate to make adjustments to suit your specific needs.

And speaking of your specific needs, we’d love to hear about how much water you bring on the trail. Are you a guzzler who doesn’t mind the extra weight, or would you rather arrive back at your car adequately hydrated, but carrying nothing more than a bone dry water bottle?

Let us know in the comments!

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