How much water do you need

Every human body is a little different, and your kidneys may have completely different efficiency from the next guy.

On the other hand, it is always possible that you don't drink enough water and therefore you stress your kidneys more than the next guy. If you get kidney stones, don't blame us.

Next time you are getting a physical exam by the physician, have him order up some lab tests, just to make sure your kidneys are good.

–B.G.–

I personally feel like I need tons of water. I'm sure some of that's psychological but I'd rather be heavy and hydrated than light and thirsty. I just don't understand some people who can go out and run 10 miles without a water bottle. To me, a gallon a day sounds totally reasonable, I've drank 3L on a 5 hour hike without needing to go to the bathroom the whole time.

Edit: Of course, I hiked almost 4 mph at altitude with a typical total gain of 5000 feet in those 5 hours so I can see why I might be at the top of the spectrum…. But I did always like to drink a lot on the AT as well.

2/3 liter water per hour

The conventional wisdom is to monitor your urine output. As long as you have at least two full-scale urinations in a day, and as long as they are not bright yellow, you probably do not have any serious dehydration going on. Normal urine is supposed to be straw color, which is a very pale yellow, but this can get fouled up if you are taking certain special drugs.
–B.G.–

Yep, very personal.
Sue and I drink way less than most – often carrying and using no more than 2 L per day (plus for cooking dinner).

>A cool sleeper I rarely have condensation.

How direct is the correlation between how hydrated you are and how much moisture forms in the sleeping bag at night?

I almost always seem to have a damp bag in the morning, regardless of conditions, which can be troublesome in winter. I always use a liner, and I don't breathe in the bag. I also try to vent when possible, and I'm not a profuse sweater.

Are some people just way more prone to getting damp bags?

To answer the OP's question: If its not terribly hot, usually 1.5-2 liters a day including food prep.

A damnp bag in the morning could be a symptom of enuresis.

–B.G.–

>A damnp bag in the morning could be a symptom of enuresis.

Ah, I was originally going to include that I've curbed my bed-wetting several years ago!

I drink 1/2 to 2/3 of a litre per hour… and that can be more in the summer heat. It really depends on the hike and the weather and how I feel.

Agree… it varies by individual. In really hot weather, pick your definition, wearing long sleeved shirt, a wide brim hat, and for some long pants will help reduce the need for water, and protect your skin.

2/3 liters during the day and more when it's really hot and 1 1/2 for cooking (tea and freezerbag) in the evening and morning

I need 8 liters to hike 25 mile waterless stretches in a day and a dry night when the weather is warm. I usually need at about 1.5 liters of drinking water if the weather is cool and I'm not hiking far. On average I drink 3-4 liters of water on "normal", not too strenuous backpacking days. If I'm pushing the miles and it's summer, I want at least 5 liters, plus water for cooking.

For one four-day ascent of Mauna Loa in Hawaii, I knew that there was no running water on the volcano. In order to be self-sufficient, I had to carry all of the water that I needed for those four days. I figured that I could get by on one gallon per day, but that meant that I was carrying 32 pounds of water at the start, plus all the rest of my food and camping gear, plus camera equipment. I got some breaks and cool weather, so my actual consumption was maybe 75% of that.

Water is heavy!
–B.G.–

I need water. I seem to always drink more water then anyone else. I think about moving or working and I sweat. A gallon a day is a normal day for me, and alot of days I will drink close to two. I am paranoid about being a heat casualty after seeing first hand many Marine's fall victim to it. It only takes one time and it will change the way your body works forever. That being said I am sorry that i stop at every water source and fill my belly with water and refill my water bottles while everyone looks at me with the look of frustration because they haven't drank any water and still have full bottles. Please forgive me.

These are great replys. Was afraid of the rants that could have rained on me. You guys are really opening up here and providing a good picture of reality on the trail.

My 1 to 2 liters per day and 1/2 to 1 more in the evening produces about 5 liters of urine, mostly at night so I was really glad to hear that it's OK. thanks

Is my math really bad, or are you saying that you drink 3.5 liters a day and urinate 5?

=

I tend to use about 4-5 liters(total) a day, "full on" hiking myself, which includes making coffee and food.

"Ah, I was originally going to include that I've curbed my bed-wetting several years ago!"

My wife cured me on our honeymoon. ;}

"Is my math really bad, or are you saying that you drink 3.5 liters a day and urinate 5?"

Not for long….

I drink around 2 gallons a day in front country. Never monitored it in the back country as I'm too busy enjoying it. If my urine is clear to pale yellow, I know I'm good.