Figure Out How Much Water to Bring Hiking in 5 Simple Steps

The most important thing to bring with you hiking (aside from your wits) is water.  But how much water should you bring hiking?  On one hand, you want to make sure you’ve got enough water to stay hydrated for the trip.  On the other hand, you don’t want to bring too much because water is so heavy to carry.   Here is how you can calculate how much water you will really need for your hike.

The Quick Answer:

Adults usually need 2 cups of water per hour of hiking.  Children usually need 1-2 cups per hour of hiking.  However, you may need more of less than this depending on whether you can filter water along the way, weather conditions, and personal thirstiness. It’s always best to err on the side of caution and bring more water than you think you’ll need for the hike.

Step 1: How Long Will You Be Hiking?

If you’ve never been hiking before, this can be a bit tricky.  Depending on the difficulty of the trail and your abilities, it will probably take you 30 to 60 minutes to walk a mile.  Or, if you are hiking with a small child like I do, it could take you 2 ½ hours to walk a mile!

Usually trail guides will list the distance and the estimated time it will take to complete the trail.  Be honest with yourself when looking at the time.  Don’t assume you can “finish the trail faster” because you are in good shape.  And, if you know you are in bad shape, add some extra time.

Step 2: Calculate Cups per Hour

The general rule for how much water to bring when hiking is as follows:

  • Adults: 2 cups (about 1/2 liter) of water for every 1 hour of hiking
  • Children: 1-2 cups of water for every hour of hiking

So, if you calculate that your hike will be 5 hours, then you need to bring at least 10 cups (2.3 liters) of water per person.  Bear in mind that these are just general rules!  Some people drink a lot more water than this.  However, it is a good guideline to go by.

*Depending on the terrain and incline, it can take a lot longer or shorter to hike a mile.  Thus, the “cups per hour” approach is more accurate than “cups per mile.”

Step 3: Factor in the Weather Conditions

Obviously, if it is a hot day, then you are going to need to drink a lot more water than on a cool day.   In hot or humid conditions, calculate 4 cups (1 liter) per hour!

Step 4: Is There a Reliable Water Source on the Hike?

I always plan  my hikes around a water source.  Because I have a water filter, it means that I don’t have to carry much water with me.

Note the water source must be reliable.  Sometimes you will go hiking in the summer only to find out that the stream on the map has dried out for the season.  There goes your water source!  But, if there is a reliable source of water on your hike, you can just calculate how much water you’ll need to the refill point.

In backcountry, you usually only need to treat water of bacteria and protozoa (even if it looks clean, there are probably some nasty things in it!!!).  In some areas though, viruses can be a problem and you’ll need a water purifier which can remove it.  Chemicals from agricultural runoff are much harder to remove from water.

Filtering water on the trail with my Sawyer Mini

Step 5: Factor in Your Thirstiness

I drink A LOT of water.  On my last hike with my daughter, I emptied our 2 liter water bladder in under 2 hours, and it wasn’t even that hot.  Since I know this now, I always make sure to pack extra water so I don’t end up dehydrated.

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