Someone on one of our recent hiking trips suggested that we should increase the amount of water we recommend carrying from 2 liters to 3 liters, particularly on one hike. I had done that hike a few years back and knew I didn't even finish my 1.5 liters on it, but it got me to thinking: how do you know how much water to carry?
It's an important question: too little water and the resulting dehydration will leave you feeling tired, headachey, and grumpy. But too much water and your pack ends up weighing more than it needs to. Each quart is 2 pounds, so 2 extra quarts means 4 extra pounds, not an inconsiderable amount.
Each person is different in what they need, and the only way to find out what you need personally is from experience. When you first start hiking, err on the side of carrying too much. For most people on most hikes, carrying 2 or 3 liters is sufficient. Carry more if the weather is hot, the terrain is challenging, or the trail is long and there isn't any chance to replenish your water supply. Drink as often as you're thirsty. If you're using a hydration system (which I personally recommend), sip frequently as you hike along. Never let yourself get significantly thirsty and if you're sweating, also be sure to stop and eat salty snacks at regular intervals to replenish electrolytes.
At the end of every hike, you should be asking yourself:
- how much did I drink?
- how do I feel?
- what were the weather and terrain conditions?
- when was the last time I peed?
This last question is important. You may be feeling fine but if its been 8 hours, you need to drink more often. The lesson for you is that you cannot completely rely on thirst or how you feel as your sole guide.
By paying conscious attention to the above questions, you will learn over time how much you need and when you need to bring more or less than usual.
P.S. The picture was taken in the Austrian Alps, where water flows direcly from springs and is safe to drink without purifying - a rare pleasure!