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How Much Water To Bring Hiking: A Guide To Staying Hydrated

How much water to bring hiking

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When hiking and backpacking, we tend to bring only the bare minimum.

But what’s the bare minimum when it comes to water?

When I first started hiking, my biggest fear was running out of water mid-trek. But bringing 10 gallons of water wasn’t an option either.

So I did some in-depth research on calculating how much water to bring hiking, with different factors in mind.

A general rule of thumb is to bring 40 ounces of water for every two hours of hiking.

In this article, I’ll show you factors you should take into consideration, as well as other things you should know about staying properly hydrated while on the trail.

Let’s dive in!

Calculating How Much Water To Bring Hiking

young woman drinking water on a hike

A general rule of thumb is to bring 40 ounces of water for every two hours of hiking.

But this is just a basic guideline that should be adjusted based on other factors. The climate conditions, type of terrain you’re hiking through, and altitude of the trail should all be factored in.

Here’s what you need to know about how each of these factors affects the total amount of water you’ll need to bring.


One of the things that affect the amount of water needed for your hike is the climate.

It doesn’t take a scientist to know we lose way more body fluids on a hot or humid day. We can lose as much as 3.6 gallons of sweat per day in hot weather, which is fascinating.

This amount depends on both our metabolic rate and how accustomed we are to a certain temperature. In other words, a Coloradan hiker probably won’t sweat as much as an Alaskan when hiking through the Grand Canyon.

On really hot hiking days, you might need to drink up to 40 ounces per hour. On the other hand, that same amount could last you two or more hours during a colder time of the year.

Type Of Terrain

The type of terrain also affects how much water your body will be losing while on the trail.

For instance, walking on sand or snow can be quite exhausting.

The harder the terrain makes you work, the more fluids you’ll lose in the process.

If you’re going on a more strenuous hike, consider bringing 20 ounces of extra water for every hour of the hike.


Here’s one thing you may not know:

Our bodies lose water twice as fast at high altitude as they do at sea level.

Fun fact: The connection between altitude and hydration was discovered in 1968, when the Olympics were held in Mexico at an altitude of 7400 feet.

This phenomenon happens for two reasons.

The first reason is that our breathing rate increases in order to compensate for lower oxygen intake. The faster we breathe, the quicker water evaporates through our skin.

The second reason lies in the dry air at high altitudes.

So, depending on the altitude you’re climbing at, you might need to bring up to 50 additional ounces of water per day.

Water Bottle Or Hydration Bladder?

person holding a blue water bottle

Considering the hydration pack was invented for this, you might think that the choice between the two is pretty clear.

Well, it’s not that simple.

I will admit – hydration bladders are easy to use. Just slip them into your backpack and take a sip whenever you want – hands free!

In fact, occasional sips are ideal for staying hydrated through the entire hike.

With a water bottle, you need to remove your backpack to take it out of its pocket. Sometimes, doing this is too much of a hassle and we end up skipping on drinking until we’re really thirsty.

And that’s not healthy.

But a hydration pack has its downsides, too.

The first is refilling. This is especially true if it’s stored in an internal sleeve. In that case, you need to empty out half of your backpack and disconnect the tube before you can reach it.

Another downside is maintenance. The tube is especially hard to clean and dry. But if you fail to do so, it can grow mold in just a few days. Because of this, you can never afford to be too lazy to clean it right after use.

Water bottles, on the other hand, are simple to clean.

So which one would I recommend?

If you can keep up with regular maintenance, a water bladder. If it sounds like too much trouble, then a water bottle is a better option for you.

What Happens If You Don’t Stay Hydrated?

dehydrated hiker

You might think that skipping on regular sips during a hike is no big deal, but the science tells otherwise.

In fact, research shows that being dehydrated by as little as 1% can affect your mood, attention, your memory and physical coordination.

By definition, dehydration occurs when the amount of body fluids we lose is larger than the amount we take in. That’s why we have to make sure we’re taking in more when we’re losing more – like on a hike.

If you’re feeling thirsty – you’re already dehydrated. And if you don’t drink some water now, you’ll soon start to show other dehydration symptoms.

Aside from thirstiness, other early symptoms include loss of energy and dry mouth. These quickly go away as we take a much needed sip of fluids.

But what if you continue to ignore your body’s messages to have a drink?

Well, eventually more severe symptoms will appear, such as headaches, cramps, nausea and dizziness.

These symptoms are the last thing you need on the trail. That’s why you should never ignore the signals your body is sending you.

Is There Such A Thing As Too Much Water?

Considering that water contains zero calories, drinking too much can’t hurt, right? Wrong!

Our kidneys are in charge of getting rid of excess water from our system. But they can only excrete around 33 ounces of liquid per hour.

So if you drink too much water, it will end up diluting the sodium in your blood. This is called hyponatremia.

The symptoms are similar to dehydration, which might confuse you into drinking even more water.

Overhydration is just as dangerous. In extreme cases, it can even cause death.

Don’t worry, though – there’s no need to be concerned about that, as long as you’re drinking sensibly.

In other words, don’t drink more than your kidneys can excrete each hour.

But it’s not just drinking too much water that can cause hyponatremia. We lose salt as we sweat too, and that can also put you in danger.

Luckily, there are ways you can balance your sodium levels while hiking. For example, try an electrolyte-rich drink or salty snack.

Purifying Water From A Natural Water Source

person collecting water from a steam in a green cup

Having a natural water source on your trail can save you some storage space.

But that doesn’t mean you can just grab a sip from that beautiful, sparkling pond of water over there. There are tons of pathogens swimming around in there just waiting to wreak havoc in a delicate stomach like yours.

A million microorganisms living in natural water sources can cause waterborne diseases. These include giardia, typhoid fever, cholera and even hepatitis A.

But there’s a way to take a sip without getting infected – by purifying it.

That way, you can turn water from any source into safe drinking water.

Water filter straws are the most popular choice among hikers. They have microfilters that only let water molecules come through, while keeping all the pathogens on the other side.

There are other options as well though, like treatment drops and purification tablets that you can put in collected water.

You need to wait for around 15 minutes before you can drink it, which can be annoying. But in case you couldn’t get your hands on a water filter straw, this is a good alternative.

4 Bonus Tips For Staying Hydrated On The Trail

man and woman on a hike drinking water

Here are a few other things you can do to stay on track with your hydration while hiking.

Hydrate Before You Hit The Trail

Drink 12 to 16 ounces of water before you even start your hike.

That way, you just need to maintain your hydration levels by continuously sipping fluids at regular intervals throughout the entire trail.

Set A Timer

When we’re out enjoying the wild, we might forget to take a sip every now and then.

To avoid that, set a reminder every 20 minutes.

Stock Up On Electrolytes

As we’ve established already, drinking too much water will cause your sodium levels to drop.

But you’re thirsty as hell. So what can you do?

A good solution in this type of situation is to pop an electrolyte gel or a tablet. They will make up for all the salts you’ve lost through sweating and quenching your thirst with water.

Dress For The Weather

Wear breathable, moisture-wicking clothing that won’t make you sweat as much.

That way, you don’t have to bring 10 gallons of water just to replenish what you’ve lost through perspiration.

Avoid The Midday Sun

Dehydration is no fun, and neither is heat stroke.

To avoid these issues, start your hike early in the morning, and find a shaded place to rest during the hottest hours of the day.

Also See: Hiking Safety Tips (How to Stay Safe on the Trail)

To Sum Things Up

Staying hydrated while doing an intense physical activity such as hiking or backpacking is not simple.

There are several factors to consider when it comes to working out how much water you’ll need, and that involves a little bit of math.

But figuring out the right amount is very important. After all, both dehydration and overhydration can put your health in serious danger.

Don’t worry, though – if you follow these tips, you’ll know exactly how much water to pack for your next hiking adventure, whether it’s a day hike or a backpacking trip.

Then all you have to do is remember to drink it often enough!

Next Up: Hiking Lunch Ideas (17 Delicious Lunch Ideas for Day Hikes)

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