How Much Water Should You Take on a Hike?

In order to keep our bodies healthy and performing efficiently for the duration of our trip, it is crucial that we take in enough fluids to replace those lost through perspiration and exposure to the environment.

But how much is just right?

Keeping hydrated while hiking

At first glance, this may seem like a silly question along the lines of “how long is a ball of string?”

Nonetheless, determining how much water to bring on a hike is a far more quantifiable and precise science than many people tend to think.

Following is a quick guide to keeping yourself hydrated and healthy on any kind of hike, no matter the distance.

Study up before you leave

Get your hands on maps, guides, and trip reports detailing water availability along your intended hiking route before you set out. If these are plentiful, you won’t need to lug as much water from the trailhead, but if they are infrequent or seasonal, you’ll have to grit your teeth and bring as much as you’ll need to stay hydrated.

*Bring along a good and efficient water purification system if you plan on using water from natural sources.

Do the math

Many experienced hikers agree that the old rule of thumb of aiming to drink one liter of water for every two hours of hiking is sound advice.

Below, we’ll examine ways you can more accurately gauge your required water intake under different conditions, as this figure may seem somewhat arbitrary and is dependent on a number of factors.

Hiking time

The first thing you should do is calculate not only the total distance of your route but also how long you anticipate it will take you to travel it. Some shorter hikes may not have as much distance covered as others, but they may require significantly more effort and time due to the steepness, ruggedness, or altitude at which they are located.

Naismith’s Rule, which recommends allocating one hour for every three miles of hiking plus an additional hour for every 600m of ascent, is a reliable method for estimating how long a hike will take. Therefore, the area around should be covered by a 9-mile hike with 900 meters of ascent.

Water quantities

After determining how long you’ll be out on the trail, you should pack enough water so that you can drink 250 ml every half an hour, or one liter every two hours. This sum is just a starting point, and it could change depending on a variety of factors…

Take into consideration all the factors

Temps

The amount of water you need to bring on a hike is largely dependent on the ambient temperature.

While the rough recommendation of one liter per two hours of trail time is likely to be more than adequate in cooler conditions, when out on a desert trail or hiking in midsummer, you will likely need to supplement your baseline allowance with an additional half liter per hour of walking in order to replenish lost fluids.

Slowest person

When hiking as a group, we can move only as quickly as the slowest member of the group, unless we’re all exceptionally antisocial. This means that we will have to put in as much time on the trails as the rest of the team, regardless of how fit or fast we may be, lest we give in to our better angels and abandon them.

Regarding water, this means packing enough to last for longer periods of time on the trail, as being out in the sun and elements can dehydrate us just as quickly at lower speeds or while waiting for extended periods of time.

Terrain

To what extent your body suffers while traversing various terrains will depend on the specifics of the terrain.

Work that requires you to be on your feet for an extended period of time or that involves navigating obstacles like scrambling or steep inclines and declines can be particularly taxing on your fluid reserves.

Level of exertion

The overall ascent and the steepness of the trail are good indicators of the level of exertion likely on any given trail, but there are a few other factors that can also increase exertions levels and have us working up a thirst in a hurry.

The two most important are our high altitude and our heavy packs. Therefore, be prepared to carry a few hundred ml of water per hour of hiking if you are lugging a heavy load or venturing onto a trail at an altitude of over 2,500 meters.

Personal metabolism and absorption rates

There’s always one person in your hiking group who drinks twice as much water as the rest of you, and someone else who drinks as little as a camel and still manages to look unfazed after taking a few sips on the longest treks.

Bottom line? Think about how much water you’ll need and adjust your water supply accordingly when planning how much to bring. If in doubt, the preceding recommendations should be followed.

How to Store Your Water

The next step, after figuring out how much water we need to take on the trail, is to decide how we’ll transport it. You can carry water in one of three primary containers: a hard-sided bottle, a hydration bladder, or a collapsible bottle.

The system you select will depend on your individual preferences, but there are advantages and disadvantages to each that you should consider.

Bottles made of hard plastic or metal

Advantages

• Easy to refill
• Measurement indicators on plastic bottles are helpful when cooking
• Durable
• It is easy to clean

 Disadvantages

• Heavier and more cumbersome than lightweight, compressible water containers
• The volume of water inside the bottle has no effect on the bottle’s physical dimensions

Hydration Reservoirs & Bladders

Advantages

• Water can be consumed without stopping or removing the pack.
• High capacity
• Easy to store and transport

 Disadvantages

• It can be difficult to restock from natural resources.
• If the temperature drops below freezing, the water in the hose is more likely to freeze.
• Accidental compression of the mouthpiece can cause contents to spill.
• Can be a pain to wash and dry out.

Collapsible water bottles

Advantages     

• Lightweight
• Easily stowed
• Liquid capacity adjusts automatically

 Disadvantages

• Poor long-term stability is common.
• Problematic in terms of hygiene and drying

Don’t Ignore the Risks of Dehydration

When we’re out on a hike, our minds are usually focused on a million different things, so it’s easy to forget to bring enough water to last the whole trip.

However, keeping ourselves adequately hydrated is essential if we want to keep our bodies’ thermoregulatory, thirst-fighting, and cramp-preventing mechanisms in good working order and avoid the far worse symptoms of dehydration, one of the most common and underappreciated ailments of hiking.

Symptoms of Dehydration

The following are some of the most typical manifestations of dehydration:

• Thirst
• Headache, fatigue, weakness, irritability, light-headedness
• Diminished urine output
• Dark or pungent urine
• Symptoms of shock
• Disorientation

Treating Dehydration

The symptoms of dehydration are easily remedied with rehydration salts, rest, and shade.

The following should be done if you or a teammate begins to feel the effects of dehydration:

• Put an end to your hike and bring the sick person inside.
• Relax in the shade with your feet propped up.
• Small sips of a salt and sugar solution or rehydration salts-infused water should be taken frequently.

When it comes to health problems, prevention is almost always preferable to treatment.