How Much Water Should You Take On British Day Hike? (Dehydration is Dangerous)

There’s nothing quite like a day hike. A chance to see the sights and explore somewhere completely new (or maybe more familiar) before the sun sets.

As with any hiking trip, staying hydrated is essential, which leads you to wonder exactly how much water to bring with you. 

Three to four litres of water is ideal for an average hiker on a British day hike. If you are a little unfit you might need more to stay cool and hydrated, and if you are used to hiking you might find yourself drinking less. 

Drinking enough water is part of staying safe when you’re hiking through Britain, so make sure you scroll down and check out our top tips and the answers to the most commonly asked questions. 

How Much Water Should I Drink? 

How much water you should drink really depends on you. The average hiker is going to go through three or four litres in a day of hiking, and that’s a normal amount.

Factor in hot weather, lack of experience, or general unfitness and you are likely to need a bit more than that. 

Another good recommendation is to drink around half a litre of water for every HOUR of hiking.

This works best in moderate temperatures, as hot or cold weather can impact the amount you drink. Try to stick to these as good guides for the amount you should be drinking. 

Dehydration is dangerous. Not only can it kill you, but it can get you killed. Dizziness can lead to you slipping on uneven terrain, the fatigue can lead to you collapsing without help.

The trail is going to be fairly isolated so make sure you come prepared

How Much Water Should I Carry?

First, quick tip, in addition to water you should also carry a sports drink like Lucozade.

This is because it helps to replace essential electrolytes that are lost through sweat and activity. Keep a bottle (or two) on hand for a quick boost while walking. 

How much you should carry is down to you. Most hikers will carry two litres at a time with them, keeping the load in their pack lighter and choosing to refill in towns or local areas.

Some carry none at all and get all of their water from local supplies through purification

Water is pretty heavy, so it’s best to avoid carrying a full four litres with you if you can. It really weighs down on your back and creates more waste once the bottles are empty.

How Can You Minimise Your Water Carry? 

The best way to minimise your water carry is to plan ahead and do so carefully. Map out your chosen trail and mark all the locations where there are potential spots to refill as well as any towns or villages you can stop in. The beauty of the UK is that you’re never far from one. 

You can also choose to drink at sources, downing a load of water to keep you refreshed for the next part of your journey.

Just be careful doing this as if you drink too much too fast you might make yourself sick(throwing up water is not fun). 

Even if you don’t plan to use it, carry a water filter with you so that you can purify anything found in local sources.

You can use this as an emergency backup which is essential if you find yourself without any water or you get lost and need a drink. 

Water Filters: How to Drink Safely 

If you stop at a river, lake, or stream, it’s not like the movies. You can’t take a gulp from your hands and then pause to look over the water.

Chances are, it’s bad water and that view is about to be ruined by your stomach disagreeing with your life choices. 

Only drink water from these sources if you have the gear to PURIFY it. Now that’s out of the way, let’s take a look at how you can drink this water safely. 

The most common parasites in water are known as Giardia and Cryptosporidium. They are completely invisible to the naked eye so you won’t be able to spot them when you take a drink.

The good news is that water purification systems can get rid of them easily. 

There are three types of water filter that you can use: 

  • Squeeze. You scoop the water into the device and screw the top onto the container. Once this is done, you can squeeze the bottle and clean water will come out. They are light, fast, and incredibly practical. 
  • Pump. With this, you stick the cord directly into the water and pump it into your drinking container. It comes out clean and can purify a lot of water in one go. The only downside is that it’s pretty heavy and clunky. 
  • Chemical. You fill your container with the dirty water and add a few drops of the chemical (safe for human consumption) and wait for the results. It’s cheap and light, but you do have to wait for it to work. 

If you arrive at a water source and find that it’s dry, there is no need to panic. All you need to do is follow the bed back to the source, and climb higher for signs of water in valleys. Found a damp, green, patch? Start digging and you’ll likely find water there as well. 

Rigid Water Bottles

This is the most common way for new hikers to carry water with them. Let’s take a look at the pros and cons as well as our favourite model you can buy. 

  • Cheap and widely available 
  • Durable 
  • Can be stored anywhere 
  • Heavy and bulky 
  • Disposable ones are bad for the environment 

Take a look at our thermo flask guides for your hikes, the flasks recommended are more likely to keep your water cold for at least 24 hours. 


  • Huge capacity for the avid hiker 
  • Designed for an easy grip while on the move 
  • BPA-free while remaining tough and safe to use 

This rigid water bottle comes in a whole range of colours so that you can pick the one that suits your style.

It is easy to grip despite its massive 2.2L capacity, so you can hydrate on the go and carry a whole supply of water in one container. Talk about practical. 

It’s versatile and secure, with a firm lid that keeps all the liquid in and stops it from leaking all over the inside of your pack.

It’s exceptionally durable so it can handle being knocked around, and also free from BPA plastics to ensure it is totally safe for you to use. 

Soft/Collapsible Water Bottles

These are a great option for hikers and you’ll find a lot of sports drinks come in this packaging. Here are the pros and cons as well as our favourite model. 

  • Incredibly light 
  • Very compact and easy to store 
  • More prone to punctures 

Green Limitless Collapsible Bottle

  • Comes in a set of four so you can carry more water 
  • Can be folded up and stored away after use 
  • Secure seal and cap to prevent unwanted leaks 

This pack of four collapsible bottles is perfect for those who like to head out on the trail and also need to save room in their pack. Made to be more DURABLE than most, you’ll find they are pretty resistant to punctures so that you can keep using them for longer. 

Filling them up is easy and fast, while drinking from them is just as simple. The secure cap prevents unwanted leaks, and they can even be frozen if you want to keep any snacks in your pack cool. They are also free from BPA, keeping you safe while you hydrate. 

Hydration Bladders

These are great for the hikers that never want to stop and they are proving a popular choice. Here’s a peek at the pros and cons as well as our favourite on the market. 

  • Hydrate without the need to stop 
  • Incredibly convenient 
  • Hard to clean 
  • Less durable 
  • Cannot drink a lot at once (a pro and a con, really)

Unigear Hydration Pack

  • A backpack and hydration bladder in one neat package 
  • 2L bladder capacity to keep you hydrated on every hike 
  • Can be used with or without the backpack, the choice is yours 

Made to make your life easier, this hydration bladder comes with a backpack included so that you can pack the essentials.

With a massive 2L capacity, it will keep you perfectly hydrated on every hike – with a long straw that reaches right around the shoulders. 

The smart airflow system used in the pack also means the water will stay fairly cool throughout the day (nothing worse than warm water) and it is surprisingly light even when full.

Durable and replaceable, it is sure to fulfil all of your needs while out in the wilderness. 

Even though water is the most essential part of keeping healthy on your hike, be sure to make sure you keep your energy levels up whilst on your hike, why not check out our article on the snacks you should take on your hike. 

Final Thoughts 

An easy three or four litres is a good starting point for any British day hike. Always ensure you stay hydrated, and check out our advice for minimising the amount of water you’re carrying – it gets heavy, and I will never make that mistake again. 

If you’ve enjoyed this instalment in our series of hiking guides, why not check out the rest? We take you through the importance of arch support, whether hiking boots are as good as they say, and other top tips for staying safe on the trail.