The Evernew Water Carry bladder is the equivalent of a Camelbak that you don’t have to drink out of with a hose, and it’s the best solution for carrying water on a day-to-day basis that I’ve found. A few months back I got sick and tired of trying to find a place for my bulky stainless steel water bottle in my day bag, and decided to try out the Evernew bladder after a friend recommended them. They are especially popular amongst the ultra-light crowd given their light weight (mine weighs around an ounce when not filled) and superior packability (they can be rolled up to the size of a hi-lighter). Another bonus is that TSA won’t take it away from you when it’s empty (or at least they didn’t take it away from me on my most recent trip) allowing you to refill it once you get through security.
The beauty of the Evernew bladder is that when it’s empty it takes up absolutely no space, and when it’s full the flexible nature of the polyethylene means that it conforms to whatever space you put it in. At first I was worried that I would quickly tear a hole or somehow spring a leak in what I assumed to be a less-than-robust plastic, but after 6-months of hard use both of mine are still going strong. I’ve dropped them on sharp granite, shoved them to the bottom of my pack filled with rigid objects, stored them rolled up and have yet to find any signs of impending failure. The cap has never come loose, and I have never had one leak. Another benefit is that they can be retrofitted to work just like a Camelbak, all you have to do is buy the hose accessory that screws on.
The bottle I use on a daily basis holds .9 liters which is my sweet spot, but you can also find them in 0.6 and 2L varieties. They are designed so that when full they can stand on a flat surface unlike the bags that come in Camelbaks. Given that Evernew is a finicky Japanese supplier, these bottles can be hard to come by, but are well worth it if you can find them in stock. I do know that Platypus has a similar system out that is equally well-reviewed, but I can’t personally comment on their quality.
Many will rightfully point out that this bladder is made out of plastic. Like many of you I try to avoid plastic products, but in this case the Evernew is hands down better than anything else I’ve tried. Unlike other containers I’ve used it contributes absolutely no plasticky odor or taste to my water. While this may not be an indication of the relative likelihood of contamination I do what I can to minimize any risk (notably, I never fill it with boiling water, or leave it in the sun for too long).
[Note: Evernew is a finicky company, and stock of these water bottles frequently come and go. Several people have recommended these Platypus bottles available from Amazon as equally useful alternatives.--OH]