How Much Water Should You Carry When You Go Hiking?

Stream on the Skookumchuck Trail, White Mountains

Stream on the Skookumchuck Trail, White Mountains

Water is one of the heaviest things in your backpack at at 2 pounds per liter it can really weigh you down if you carry to0 much of it when you don’t need to. I used to do this all of the time, first as a day hiker and then later as a backpacker.

As a day hiker, I used to carry 3 or 4 liters of water for a long summer hike, even though I was surrounded by water sources in the mountains where I hiked. I hadn’t learned to use a water filter yet, and would often turn back when my water started to run out rather than resupply from the streams at my feet.

I can still remember the first time I used a water filter. It was on West Hunter Mountain in the Catskills. I stopped at a stream and pumped 2 liters of water into my platypus hydration system.  It was one of the most liberating moments I’ve ever experienced hiking! I knew from then on, that the distance I could hike in a day would never be limited by the amount of water I could carry in my pack.

But even then, I still carried two much water between fill-ups, especially on backpacking trips. I’d often carry 4 liters or more in my pack at any given time, even when I was experimenting with lightweight backpacking.

This was brought home to me a few months back when I met a trip leader I used to hike with a lot in those days. The first question out of her mouth was whether I was carrying too much water still! I can’t believe she remembered that about me after all those years.

Nowadays, I carry a lot less water with me on day hikes and backpacking trips, and top out at 2 liters max. If I need more, I just stop and filter some. Granted I mainly hike in New England or on the Appalachian Trail where water is plentiful, but it’s something to keep in mind. I’m not suggesting that you drink less, but that you carry less:  I still manage to drink about 5 liters a day regardless of whether I’m day hiking or backpacking.

Here’s my system:

  • I pre-hydrate by drinking a liter of water just before I start hiking because carrying water inside you is lighter than carrying water on your back!
  • I start out with 2 liters and drink about 1 pint every hour.
  • I plan my route carefully so I know where there is water if I run out, and can carry more if necessary.
  • I camel up when I resupply at a stream or pond, drinking a full liter on the spot.
  • I drink a liter at the end of the day, after I’ve finished hiking.
This is pretty much what I do year round, except in winter when I don’t resupply during the day if I need to melt snow. I still pre-hydrate (although a bit more) and carry a maximum of 2 liters unless there’s something about the route I’m on which requires that I carry more.
With a little planning and a water filter or purifier, you can really cut down on the extra water weight you have to carry during the day. It really is liberating to have a lighter pack and be more self sufficient, especially when you develop the urge to hike all day.

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48 Responses to How Much Water Should You Carry When You Go Hiking?

  1. Phil Reed's Hikes May 14, 2012 at 6:25 am #

    Very good point. “should be” obvious, but it’s not, well said.

  2. Blitzo May 14, 2012 at 6:32 am #

    I also carry 2 liters as a “standard” load. I see many hikers carry 1 liter most of the time, but never seen many carry more than 2 in water rich areas.

    The bigger question is… when in dry areas where you have to carry for s significant distance, how much water per mile? I use water per mile instead of time because that’s usually what you have to work with – X distance to the next water hole.

    You said you carry 1/2 liter per hour. Translating into 2 mi/h hiking speed, that’s 1L/4mi. That’s pretty close to what I carry. My standard formula is 1 liter per 5 miles, then adjust for weather or terrain. Over 90 degrees – subtract one mile. Over 100 degrees – subtract another mile. Under 70 degrees – add one mile. Under 60 degrees – add another mile. Think the terrain is such that you’ll hike faster than 2 mi/h – add a mile for 2.5 mph and 2 miles for 3 mph. The same for the other direction – subtract 1 mile for 1.5 mph and 2 miles for 1 mph. I’m not an experienced winter hiker and I know water consumption goes up as the weather bets below 40, so I’ll let you and others fill in that part of the formula.

    The other part of the water formula is camping. Carrying water to a dry campsite, then camping, then hiking past to the next water source is the next thing to calculate. All the distance formulas apply plus a constant for camping. Most people stay a little dehydrated throughout the day and need to rehydrate at night, plus cooking, plus cleanup, plus hygiene. Whatever you plan to eat for the X meals you will be without water is a given. How much you need to rehydrate with is a personal thing – I use 1 liter, and I do it in the AM mixed with orange Gatorade to make fake orange juice, not the PM to avoid the midnight urine fairy (yes, I know rehydration takes time and should be done ASAP). I try to pick foods that require little or no cleanup to avoid using that water. Hygiene also tends to be the bare minimum on dry camp nights (maybe 2 oz). On average, about 1.5 liters covers me for camping.

  3. Michael Blair May 14, 2012 at 6:48 am #

    Monica and I did a day hike in the Adirondacks a couple of summers ago when I set my personal water consumption record – 12 liters. Had the pre-hike liter, carried 3, and refilled 2 times. At both refills downed at least a liter each time. Learned the value of trailside fill-ups vs. lugging it all from the start. Still something I need to get better at though.

  4. Ray Anderson May 14, 2012 at 6:54 am #

    I carry water based on availability. But no matter what I decide, I always have one liter hidden in my pack for “hiker down” or any other emergency. Once I met a man and his young son who were so dehydrayed that after I handed them my emergency bottle, he tried to write me a check!

    • Jess May 22, 2012 at 1:44 am #

      Good on you, though that’s heavy kindness. I ran into someone on the trail once who was dangerously dehydrated. I’d given her half a liter further up the trail, but was basically out at that point ’cause it’d been a long stretch without water. It was easy enough to drop pack and run ahead to the next watering hole though. I guess it depends on how wet the area you’re hiking in is though and how much you trust your map/guide/ability to find water.

  5. Chad May 14, 2012 at 8:45 am #

    This is one of my biggest issues as a Scouter in Texas. I carry a 3 L bladder and depending on the weather, I suck that thing dry quick. The lakes we hike usually have zebra muscles in them and so we can’t filter. So I am still trying to perfect the amount of water I carry. I have two additional 1 L platys I carry if needs be. I am going hiking this weekend with my boys and I have gone ultralight with a REI Flash 18, my 3 L bladder and my tarp and air pad strapped to the back. My fat body appreciates that I am trying to cut down my 60 pound pack to under 20.

    And have you ever tried drinking filtered water from the Brazos River? Tastes like HOT liquid dead fish guts. That was a tough High Adventure.

    On a small side note, some of my Scouts “borrow” water from other boys. I find this practice confusing as how does a boy turn down a friend for water. But in the end if they are both thirsty, it is one of those teachable moments. This is also the hike where I ran out of water and so did half of my young Scouts. Learning moment for all of us!!

  6. Serena May 14, 2012 at 9:00 am #

    I never thought that I carried too much water, but now I may look into that! We ran out once and ever since then I load up. I did enjoy the mention about how excited you were the first time you used your water filter. I recently got one and also had that wonderful feeling knowing that I could grab water on a trail now – a big help during a hot Georgia summer!

  7. Pat May 14, 2012 at 12:10 pm #

    It depends on how available it is. Even when it’s plentiful I still prefer to carry a quart in a Nalgene and a 100 oz Camelbk bladder. Last summer I was doing some hiking in some higher elevations that had no water. It was probably in the 80′s that day. I carried a 100 ounce Camelbak bladder, an extra quart of water in a canteen, and two one quart Nalgene bottles of Gatorade. At the end of the day I only had 16 ounces of water and about 12 ounces of Gatorade left.

  8. Hikezilla May 14, 2012 at 12:36 pm #

    I think in my 1500 miles or so of hiking and backpacking I only ran out of water – to the extent I thought I was in danger – only once. I was still in college and a friend and I decided to overnight up to Mt. Chocora in NH in late 1977 August. 85 degrees. We started off with zero water but with lots of tequila. Halfway up there is a side trail to some falls (and water) but we decided to get to the top first because I could see in my White Mt Guide book map there was a stream on top. Yea right. August. In the Whites. Once on top we were really starting to feel the dehydration but the “stream” had withered to a soppy puddle. And I was filterless. I’m not even sure I knew about filtering back then. I convinced my hiking partner (now that he was sure I had no clue what I was doing) to head straight for the closest guaranteed water supply. That meant down hill on a trail we had not planned on go on. We followed the slope of a valley on the Bee Line trail until we crossed a vigorous stream. I swear I could hear it for 30 minutes before we got there. I was so parched I could taste the water. I imagined what I would do when got to it. Flop on my face? Lie down in it? When I finally arrived I knelt down and put my face in that stream and sucked that pure, cool H2O into each cell in my body. Total satisfaction. Then it rained for 10 hours straight…

  9. Kristin May 14, 2012 at 1:15 pm #

    Here’s a question from a novice: What does water you filter from streams taste like? I don’t yet have a filter, and haven’t taken any trips long enough to need one, but I will soon. Have to admit, though, that I’m nervous about drinking from streams even though I know my filter will protect me from illness. Just call me wimpy!

    • Michael Blair May 14, 2012 at 1:39 pm #

      Hopefully nothing :-)

      You could always bring some powdered gatorade to add to the filtered water if you are nervous.

      • Kristin May 14, 2012 at 1:51 pm #

        Thank you – I think that’s what I’ll do!

        • Walter Underwood May 14, 2012 at 6:49 pm #

          Don’t bother with a filter. It is heavy, fussy, and expensive. I’m not sure how the filter craze got started.

          Chlorine dioxide is the best treatment we have today. You can use Micropur tablets (easy) or Aqua Mira (cheaper).

          With Gatorade, that Brazos water will taste like hot lemon-lime fish guts. That might be an improvement. In most of the mountains where I have hiked, the water tastes fine.

          • Chad May 14, 2012 at 6:57 pm #

            Nasty!!

            • Tom Murphy May 21, 2012 at 10:45 am #

              If the taste of your filtered water is a priority, then a First Need filter is an excellent option. Too heavy for me now for most trips, but I still bring it when I know stream are running very low and/or the water sources are marginal.

    • Jess May 22, 2012 at 1:39 am #

      Ah, man, filtered water from a good mountain stream is the best. When I first started hiking with a filter I became a water snob. We’d say things like “Oh, this one has a nice granite base with just a splash of mossy flavor”. Too much fun. Sadly I got too impatient and carry iodine now, which hides most of those complexities.

      Don’t be afraid to drink the tasty looking water straight from the filter though. It might make you dump out the rest of the your city water. :)

    • Brian Berggren May 24, 2012 at 12:08 pm #

      Kirstin some filters have activated carbon in them and will remove some unpleasant tastes or odors.

  10. Grandpa May 14, 2012 at 1:43 pm #

    For me when hiking in Texas, the water usually tastes like lemonade, hot chocolate, coffee, ramen noodles, etc. After I filter and/or zap it with iodine or chlorine dioxide, I generally flavor it after waiting the appropriate time. When I’m in Glacier National Park with my brother, the water after treatment tastes fresh and great by itself.

    • Kristin May 14, 2012 at 1:52 pm #

      I think that I will flavor it at first, and then go from there.

  11. Grandpa May 14, 2012 at 2:41 pm #

    Other advantages of flavoring, especially when hiking with the grandchildren, are that they’ll drink more flavored water than plain water. Also, with some sources, the water after treatment still isn’t exactly clear because of tannins, etc. The flavoring imparts color to make them think “grape” or “orange” rather than “decayed leaf sludge”.

  12. Hiking Dude May 14, 2012 at 3:04 pm #

    Nice post.
    On last month’s AZ Trail 800-mile hike, the most I carried was 5.25 liters but usually under 3 liters. I like Blitzo’s formula as a guide. Take into consideration terrain, temperature, miles, meals, and days. I found I go about 8-10 miles on a liter as a guide.
    If I had only had 2 liters on some parts, I’d be dead. Carrying an extra liter is sort of like a 2.2 pound insurance policy.
    Water is 1kg/liter, or 8.3lbs/gal, plus the container. A nalgene is an awful heavy way to carry water compared to free, disposable water bottles or collapsible Platypus-style bags.
    I use a Sawyer Squeeze filter and it worked great for me the whole trip.

  13. Laura May 14, 2012 at 10:54 pm #

    Hot chocolate mixed with Nescafe Instant Coffee in the morning is better tasting than any Starbucks. I also use a water filter with a pump, and adding flavor to it is definitely the way to go. I carry all sorts of flavors using Crystal Light, South Beach Diet (with protein added) and Propel. The best part is, these flavorings for your water are light weight and weigh next to nothing, nor do they take up much space. If you are watching the weight of your bag, adding these packets are the way to go.

  14. grant May 14, 2012 at 10:57 pm #

    Nice post…I commonly struggle with this issue and usually end up carrying a full gallon! At the end of a hike I sometimes forget I had a full Nalogene buried deep in my pack!

    Do you drink straight water or do you add any type of electrolyte tab to it?

  15. Grandpa May 14, 2012 at 11:40 pm #

    I mix in some Alacer Electromix electrolyte powder I buy online in packets that treat a liter at a time. To me, Gatorade is lime flavored sweat and for a long time I drank only water–until I passed out twice from hyponatremia a couple years ago, incurring a severe high ankle sprain and broken ankle in the process. After that, I started adding the electrolytes and haven’t had the dizzy room-spinning experience since.

    I also do what Laura suggests, mix hot chocolate with instant coffee–good stuff!

  16. Diane May 15, 2012 at 8:41 pm #

    I figure 1 liter for every 2 hrs, and have started to carry more sports powders or bottles to avoid electrolyte imbalances. depending on the hike plan, I can carry less water if I bring my purifier…one of my favorite pack items. I have the ceramic katadyn Vario Water Filter. and have filtered some pretty muddy water into potable water. I will admit i did boil it anyway for 3 minutes just for peace of mind this last trip. The filters do have a limit to their life and I just realized the cost of the replacement filter $39. Still worth it to me and I will still share it,,,but bring some coffee filters to prefilter with One of the pluses is to be able to attach the right sized hydration pack onto the pump for filling. I found an online store that had them for a really good price. The Skilcraft 3L Replacement Hydration Bladder is only $5.99, lightweight, and fits the Vario. Shipping is through UPS so you’d have to order a few to absorb the shipping charge. http://www.unclesamsretailoutlet.com/

  17. Brian Green May 17, 2012 at 3:42 pm #

    Philip, did you really mean to say that water weighs less inside you than it does on your pack? Did you mean that it ‘feels’ heavier to carry it than it does to drink it and have it inside you? Care to elaborate :)

    • Earlylite May 18, 2012 at 4:41 pm #

      Brian – of course water weighs less inside you than on your back. All *really* experienced hikers know that! Seriously – that one always gets a laugh at my talks.

  18. Esther May 18, 2012 at 8:24 am #

    This also seems obvious but to the novices from a former novice…. Make sure you check current trail reports (blogs, forums, etc.) For reports on water availability at known sources. Last year in Grayson Highlands/Mt. Rogers Virginia we found trusted water sources dry. We knew this and came prepared with info from other hikers on lesser known sources but we encountered many others who were panicked because the mapped water was dry.

    FYI filtered water from a cow watering hole doesn’t taste that bad!

  19. Marco May 18, 2012 at 10:24 am #

    Water tasts great, no matter what is in it if you are genuinly thirsty. I usually carry about a liter or so (two 500ml bottles.) I use Aquamira for killing stuff in drinking water.

    Boiled water will always work. I get tired of hot tea or coffee on a warm day, though. As Philip says, there is often water available before it is really a problem. Dry camps, can be a problem. But this goes with planning. If it is a long haul, then you HAVE to carry the water you need. Carry an colapsable water bottle if needed, fill it up at the last watering hole.

    For drinking water, I have a salt shaker filled with salt and lite-salt for whatever I have needed.About 3:1 is what I fill it with…not to fussy about measuring it. A shake will be PLENTY for a bottle, it doesn’t take much.

    Water is heavy, You do not have to worry about hydration so much as just maining good regulation. Sweat means cooling off, not hiking so hard or slowing down. In cold weather, Again, slowing down will help slow your breathing and loss of water. You get further at the end of a day than forcing fluids out, along with all your body salts. Sweat has 3-10 times the salts in it than normal cooling.

    Filters are good, but, AM is more reliable, generally. UV is quick, but heavier. Anyway, some things you cannot remove from water, easily. Mineral salts, iron salts (sulfer water,) and a lot of other stuff does not filter. Polutants cannot always be filtered out, avoid larger streams and rivers. Tannic acid is not the best, but tolerable for a long time. Again, filtering does nothing to remove it. Nor does AM. Boiling can remove gasses, iron sulfate, and the like. But may make some things more concentrated. A clear mountain brook is often clean, but you had better use cautiion with some of the waters, there. No telling what animal has died or crapped in it above you. That said, I often don’t bother in the ADK’s. Tannins are sometimes quite bitter, depending on how much.

    Carry what you need between each watering hole. It is not immediatly debilitating to go without for a day. But, it WILL catch up with you. Few of us can survive more than 2-3 days without water. Going for 4-5 hours without will NOT hurt you. But you will need to spend a half hour or so rehydrating later on.

    Cammeling up is OK. But your body can also adjust to a water shotage. 2 cups will let you flush your blood stream. But temper this with heat, humidity and overall conditions. Your body finds it easy to get rid of the excess, but not as easy to replace it, sometimes. You rarely hear of too much water causing a problem. But, too little will.

  20. bronson May 18, 2012 at 9:10 pm #

    i live in the applachians in NC i hike a 25.5 mile trail with only 2 holes actually crosses and sometimes if it is a drought their is no water how much should i carry?

    • marco May 18, 2012 at 10:22 pm #

      For a straight through hike, you will be fine with 2-3 liters. For overnight, cooking, cleaning up, misc water use…I would bring at least four or five. This assumes 80-90 as the highs and only 3000-4000′ elevation change. I did similar(about three times the elevation changes, though) at a lower temp (high was 60) last fall with 3 liters, soo, add one for the temperature and one to be comfortable with the hike. Lots of things can effect your consumption. Rain? Cooler weather? Hotter?

  21. Barbara D. Russell May 19, 2012 at 7:05 pm #

    As a budding naturalist, my graduation “final” was spending 5 days in survival with 20 classmates in the Pacific Northwest wilderness. We had no knife, no tent and not even a lighter or blanket. Just the clothes we were wearing. We all survived on a baby duck, 2 garter snakes, and some wild edible plants. While there was a fresh water spring dripping nearby, it was not easy to get the water. I drank as much as I thought I needed, but I didn’t drink as much as I should have. The day after returning home, I fainted at a local diner while waiting for my meal to be brought to the table and ended up in the hospital emergency room. The doctors tested for all sorts of microbe contaminants in my body. The water we drank turned out to be pure. My problem was I didn’t drink enough of it, and I took in 2 liters of IV fluid. As a second generation member of our hiking in Europe family business, RussellTours.com,I do not fail to pass on this valuable Lesson Learned. Thanks for touting the ease of using, and carrying, a good quality water filter. It may help others avoid the pitfall of dehydration.

    • Earlylite May 19, 2012 at 7:29 pm #

      Fantastic story and lesson learned. – glad you made it out ok. Thanks for sharing this excellent advice.

  22. Dan @ ShareThisAdventure May 19, 2012 at 8:44 pm #

    Great post, taking way to much water was one of my biggest mistakes when I first go into backpacking… so much easier to take some iodine or filters…

  23. Diane May 19, 2012 at 9:55 pm #

    don’t forget that your physical condition and hiking speed will be a determining factor for how much water, and food you will need on the trail.

    A hiker who is less fit, will reach a higher heart rate faster and perspire more than the athletic hiker. Time and exposure. He will be out there longer, not reach the water source as fast and may run out of water before expected.

    My favorite story for this was in the White Mountains- my group is always slower and on our Bonds trip we planned on refilling when we descended into Lincoln Woods. Everyone was dry about 45 minutes before that and thankfully there were some pot holes of water at the summit to filter. Well these potholes are a source of relief for many. There were photos of a dog rolling in them online…And I’m sure some toes were cooled too at some point.

  24. Jess May 22, 2012 at 1:36 am #

    Heh, it took me way too long to learn that if I tried drinking more than about half a liter of water at a time I’d just pee it out. Luckily I did most of that learning in wet places so it wasn’t too heavy. :) I try and pace myself a bit more now.

    Reading your story about the first time you used a filter made me smile. It reminded me of the first time I stopped using a filter and switched to iodine. Just being about to stop for a moment at a stream (only slightly longer than a pee break) to fill up was powerful. Our old filter was a slow gravity powered thing that just ate time. I still use iodine, but I’ve stopped using the pills ’cause they taste nasty and switched to using polar pure. I’ve found that only tastes bad if I don’t have enough vitamin C in my system or I’m low on salts. I generally carry a salt lick and some electrolyte mix to help with that. I wish I could find a way to ditch the electrolyte mix entirely, but I haven’t found it yet.

  25. Dave May 22, 2012 at 3:45 pm #

    Sawyer 3 way inline water filter. Very light. Connects to bladers easily. Can be used as a gravity feed filter in camp. Can be attached “in line” on your drinking tube inside your pack and you can fill a blader with dirty water and drink from it. Filters out all nasty bugs.

  26. peabody3000 May 24, 2012 at 10:53 am #

    for treating water that’s already reasonably clear and clean, aqua mira is a great choice over iodine. it doesn’t impart a noticeable flavor (extremely important to me) and it kills all the bad stuff. the only potential consideration is time since it takes 20 min to work but i haven’t had issues there. i fill micro droppers with the stuff and the result weighs just a few grams

  27. Melissa May 24, 2012 at 11:51 am #

    Trouble is, you need to plan your water re-supply for up to 4 hours in advance, depending on what might impact your water source… the wait for water tablets to kill Giardia is 30 min, but it’s 4 hours for Cryptosporidium.

  28. Evan Ravitz May 24, 2012 at 12:08 pm #

    Until consumer-priced filters became available in the ’80s, most people drank mountain streams directly, as I still do, and have for over 50 years. Having traveled and backpacked and cycled extensively in Mexico and Guatemala I learned how to deal with amoebic dysentery, which is much worse than giardia, and Ascaria worms, the most common kind. ALL can easily be cured -without inhibiting your trip- with the herb quassia, or common broad-spectrum antibiotics, IF you treat it promptly and understand the process. I’ve put what I know at: http://spryeye.blogspot.com/2012/05/cure-intestinal-parasies-naturally.html

    So now I carry a 1 oz bottle of “yodo” from any Mexican pharmacy, which used to be iodine, but now has a different active ingredient -in case I have to drink from a suspect source, like Boulder Creek in town here. And if my trip is longer than 20 days -the incubation time of most parasites, I carry a couple of ounces of quassia.

    This way I’ve built up a solid immune system against mere bacterial problems, which you won’t do if you filter all your water. And I spend zero time pumping.

    • Melissa May 28, 2012 at 1:45 pm #

      Thanks for these tips and your blog about building up immune system!

  29. Mike Conlon May 24, 2012 at 7:19 pm #

    When I meet hikers going the opposite way, if there are any, I invariably ask when the last time they crossed water was. Particularly in dry areas this keeps me from carrying too much water. It’s comforting to know that, despite no water being shown on the map, I know that a good water source is only two hours up the trail.This often saves me lugging around an extra quart.

  30. Bill Walker May 30, 2012 at 1:14 pm #

    Great and knowledgeable discussion. I would just add one thing. The more time you spend out there, the more likely it is that you will end up just drinking water straight up. The rules are pretty simple: the higher the elevation and narrower the stream, the safer the water source. But please don’t get too greedy. Many hikers on the Appalachian and Pacific Crest Trails (including this one) rotate water filters, etc. out at post offices along the way, depending on what the guide books say about the water in that section. In Pennsylvania, for instance, you would be more likely to carry a filter. However, in Maine many hikers send their filters home.

  31. Beth Campbell August 21, 2012 at 8:42 pm #

    Great post, i normally just take a bottle and a filter and just stop and drink wherever necessary. Will probably give powdered gatorade a go, as it sounds like the best option so far. thanks for all the great tips. keep up the good work. :)

  32. Ross October 5, 2013 at 1:04 am #

    I’m new to the whole water filtration thing and concerned about your mention of zebra mussels. I’ve been searching the web for a while and can’t figure this out. Why can’t you filter from lakes that have them? The only answer I can find is that you might risk moving them to another lake, and as an invasive species that would be a bad thing. My concern was that they might pose some kind of health risk.

    If the no filtration rule is due to them being invasive, boiling or chemical treatment would still be safe for every one (aside from the zebra mussels), right?

    • rory February 13, 2014 at 4:40 am #

      Ross, I think it may be because Zebra Mussels cause algal blooms.

  33. Scott October 25, 2013 at 3:43 pm #

    Love the article. Not all filters are created equal, so it’s good to invest in a good one. I am guilty of overpacking water, too.

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