Staying hydrated is as important as nutrition, even more so when you’re out on a hike. It’s not always obvious how much water to bring hiking but I hope that after reading this post, you have more of an idea. For the average adult, 60% of the human body is made up of water so yes, the amount of water consumed per day is kind of a big deal.

Think about how you feel when you get dehydrated on a normal day. You might get a light throbbing sensation in your head, you’ll crave fluid (not always water, depending on your habits), get mild heart palpitations, dizziness and an all-around feeling of being lethargic.

How Much Water To Bring Hiking

If you don’t stay hydrated during the day then eventually you’re bound to feel one or more of these symptoms. Going on a day hike or longer is a form of exercise and depending on the conditions, dehydration can kick in ten times faster so the amount of water you take needs to be made an absolute priority.

In my very early days of hiking, I sometimes made the mistake of not taking enough water and I learnt my lesson quickly. There’s no worse or more despairing feeling of knowing that I’ve run out of water and still have another ten miles to go until I’m back at the car.

How Much Water To Bring Hiking


The simplest answer to this query would be: it depends.

It depends on a variety of factors:

  • What weather conditions will you be hiking in?
  • How long do you plan to be out on the hills?
  • How much weight will you be carrying?
  • How many donkeys will accompany you on your hike?….

Just kidding with the last one, but the point is that there are a variety of things to consider.

A good general ballpark figure I like to go by is to drink about a litre every 2 hours. It’s not uncommon that I drink a lot less or a lot more than this, it really depends on the scenario. I recommend that you shoot for this as well, try and make it a habit to take a sip of water every 10 minutes or so. The idea is to not get dehydrated or start to feel thirsty, taking small sips as you go is the best way to remedy this.

I tend to always take a hydration pack with me, the one below carries 2 litres of water.

Hydration Pack Of 2 Litres

Remember, if you feel thirsty then you are already dehydrated.

If you are hiking on a boiling hot day at high altitudes then you’ll sweat more and may find that you need a litre every 1 hour, maybe even less. If this is what it takes, then this is what it takes. Your hydration needs to be a priority.

This also applies in the winter; we don’t always associate cold weather with dehydration but you would be very surprised. What happens in freezing conditions is that our blood vessels constrict, preventing the blood from flowing to our extremities. Your body then draws blood to the core which is a fooling mechanism making your body feel like it’s not actually thirsty. This makes you need the toilet more, thus making you more dehydrated.

Familiar with it being so cold that you can see your own breath? Well, that’s more water your body is losing in the cold weather!

Mountains around Loch Quoich in winter

The point is that, regardless of the season, staying hydrated is incredibly important when you’re out hiking.

If you’re a keen hiker who hits the hills several times a month then your fitness will be significantly higher than someone who rarely goes out hiking. If you fall into the latter category then you should think about taking extra water. If you do other forms of exercise in between monthly hikes, for example, then you should be okay but it’s still better to be safe rather than sorry.

You may have read about or seen different ways of calculating your sweat rate to work out how much water you’ll need but I really think that this is overkill. It doesn’t need to be this complicated, the main thing is that you know how important water is for your body. There are far too many variables for this to be an accurate calculation and your best bet is to listen to your body.

Remember, one litre of water weighs about one kilogram so it’s not light. For a shorter hike, I’ll always take a full hydration pack of 2 litres. If I’m going for an entire day or if conditions are particularly hot/humid then I’ll take an extra two bottles of 750ml – 1 litre each.

Does It Have To Be Water?


Not necessarily.

Water is the best and most natural way to stay hydrated but if you don’t like it or would prefer something else then there are a couple more options. Lots of people think about these ‘hydration drinks’ which are packed with electrolytes. Be careful with these, however, because lots of them are high in sugar which won’t actually do a great job at keeping you hydrated.

Powerade for energy

Sugary drinks (like Powerade and Lucozade) are more relevant for someone doing a marathon, for example, and is a quick energy booster to increase blood glucose levels while they’re on the run. I’m betting that if you’re on any sort of lengthy hike that you’ll be taking some food with you so that’ll do the trick for you, whereas someone running a marathon doesn’t have time to sit down for lunch!

Another strong advantage of using these electrolyte drinks is that they sometimes taste good. If they taste good then this increases your likelihood of staying hydrated, especially if you’ve been guilty of not doing so.

All in all, you can never really go wrong with water. Electrolyte drinks are also fine but as I mentioned, be careful with the sugar content. This article does a good job of analysing the pros and cons of Gatorade.

In addition, it’s a no-brainer to avoid high caffeine and any alcohol at all costs – these will have negative effects.

Can I Refill With Water From The Hills?


Definitely! Using the natural sources means that you can hike for as long as you want without worrying that you’ll run out. This also improves your hiking skills and is great for boosting your confidence.

Generally speaking, the water quality in streams and lakes etc in the UK or Scotland are perfect, often tasting better than bottled water!

I can’t speak for other regions and if you’re not entirely sure about how it is where you are then you can easily buy a simple filter product.

Rivers and Lakes water sources

Is It Possible To Drink Too Much Water


It is possible but extremely unlikely so I wouldn’t worry too much about this – especially out hiking. When you drink too much water, a condition called hyponatremia occurs which is when electrolytes in your blood are diluted. This is dangerous and is more commonly known as water intoxication.

An example I have seen of this occurring was from this article here. The subjects consumed between 10 and 20 litres of water in the space of a few hours. This was under normal conditions and not intensive exercise – so you have nothing to worry about!

If you find yourself urinating a lot when out hiking then you may be drinking a bit too much but this doesn’t really matter, it means you’re hydrated and having to stop to do the business is an inconvenience more than anything.

Too much water

What I Do


Here is what I do when I’m going out on a hike:

  • I always make sure that I carry a full 2-litre hydration pack with me. This is usually just on a short hike (2 – 4 hours) and if I’m going out for the day, or if it’s a short hike in hot conditions, then I’ll take an extra 2 full bottles.
  • I only take water and have never needed anything else. Even on brutal, 12-hour treks through the wilderness water is enough for me.
  • I consume a litre before I start the hike to make sure I’m well hydrated when I set off.
  • I’ll take sips of water from my hydration pack every 10 – 15 minutes and make sure that I still have plenty of water for the second half of my hike.
  • I have a full bottle waiting for me in the car (or wherever I start from) to hydrate as soon as I finish.
  • Most of my hiking experience is in Scotland where the water is clean and fresh so have never needed to take a filter. In other locations, I would be more inclined to do so.

Extra Tips


  • Drink lots before you go – whether this is with your breakfast or in the car on your way to the starting point. It means you’re well-hydrated when you start.
  • Get a bit of salt with breakfast or in your meal the night before. Sodium helps the body absorb water and use fluids in the right way.
  • Use your urine colour as a ‘hydration indicator’.
  • If you’re very focused on speed and want to reduce weight then you should consider investing in a water filter and rely on water from the hills.
  • Plan your hike beforehand so that you know where there are water sources as you go.
  • If you’re hiking in the snow you can put snow in your water bottle to thaw into water but if you’re doing this I recommend that you use a filter.

Final Verdict


Hydration is very important, there’s no doubt about that.

H2O image

The amount of water you should be drinking out on a hike is purely down to you. As I’ve already mentioned, a variety of factors need to be taken into account such as age, fitness, weather conditions, hike length, and more.

The bare minimum for me, no matter where I am or how long I’ll be out for, is to take 2 litres. From here, the amount only increases depending on conditions.

Use your body and senses as a gauge; if you’re thirsty then you’re most likely dehydrated. The best way to avoid feeling parched is to follow my advice from before and get into the habit of taking small sips every short while.

Don’t be put off by the weight of water, it’s important to realise how important your hydration really is. Hopefully, this short guide on how much water to bring hiking has been useful and provided you with the information needed when preparing for your next hike. Thanks a lot for reading and if you have anything else to add then please don’t hesitate to leave a comment in the box below. 🙂

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