HYDRATION

You can set up some training runs or run some events in which you may not have to carry any water. This is rare for trail runs and races as they are typically not in places where water is convenient. Usually, you will need to carry some and maybe a lot of water. There are a million ways to do this. Canteens are no longer the norm. High tech hydration packs and water bottles are where we live now. How far you are running will determine how much water you need to carry. Some decisions you need to make are (1) Bottle or Bladder? (2) Carry it in hand, on your back, or on your waist? (3) How heavy is it? (4) How comfortable is it? (5) Do you need additional carry space? (6) How much does it cost?

(1) BOTTLE/BLADDER: There are couple varieties of hand bottles. Some are hard unbreakable bottles like Nalgene, some are squeezable with a squirt hole on top, while others have a wide mouth. You could just buy a single water bottles from a convenience store. You can get a neopreme handle that slips onto the bottle, or jerry-rig one from duct-tape. Really come down to what's available to you and your preference. Camelbac now comes in a dozen varieties and copycats are making many others. The bladders can be put into backpacks, waistpacks, or anything else large enough for them to fit into. Sizes range from 40 oz to 100 oz or more?
(2) HAND/BACK/WAIST: Most people start with hand bottles as they are the cheapest and easiest to adapt to. But the more you run and the further you go, odds are you will be looking for some means to carry more water. Two bottles? Now you need a place to carry one of them or you have NO hands with which to carry your flashlight, or eat. The fanny pack will be your next buy. Do you want the bottles poking strait up or tilted sideways? Might depend on the shape of your butt. If you have a big butt or a small waist then the bottles will likely be poking you in the back. A sideways tilted bottle belt resolves this problem. Then there are the 2-bottle belts so you have both hands free, or maybe you need 3 water bottles, so you carry one and store both of the others behind you. The bladder companies now have a waist bladder with a slick setup. The waist bladder keeps the water closer to your body than the heavy bottles hanging like bricks off your backside. All of these options wrapped around your waist applies additional weight and pressure to your stomach. If you have tummy problems, you may wish to switch to a back bladder system. These come in different options: on your back, over your shoulder, and in a vest. The vest is handy with it's additional front pockets, but anything covering my chest is bad for air circulation. Anything blocking the wind from moving over my chest on a hot day and I'll overheat sooner than usual. I avoid anything that covers my chest. The backpack option keeps the water behind me and resolves the air flow problem, but I have to do without pockets. Anytime I need something from it, I have to take it off. But my hands are free and it works just fine.
(3) WEIGHT: Lighter is better. Keep in mind what it will weigh when the bladder is full. You won't be carrying it empty - you hope! Some adventures will require you carry much more than water. You'll need more storage capacity. Some systems have hooks, straps, pockets, and mesh. Everything you add in the way of hooks, straps, zippers adds weight. If all you need is additional water, I suggest you find the lightest bladder system. I own a full pack bladder system that weighs less than some much smaller systems. Regardless what you will use it for, find the lighter system.
(4) COMFORT: If it's not comfortable, you'll either not use it. or use it in pain. Some people don't like pressure on their stomach, while others will only carry hand bottles. Are the shoulder straps comfortable or do they wear blisters on your shoulders? Does the waist strap loosen as soon as you start to run? Do you need front pockets? Comfort is very important and you'll find out usually at the wrong time that the system you have on has a problem. You need to really think through what you need it for and test it on a few long runs as soon as possible. Wear it around the store for awhile with some weights in it.
(5) SPACE: Do you need a 40 oz or a 100 oz bladder? I bought 2 different size bladders and put whichever one I wanted in the camelbac that has all the other options that I wanted for that particular run. I mix and match the systems for each specific run. I usually just use the 100 oz and put in less water if I don't need to carry that much weight. The Cloudwalker I have has an enormous amount of capacity, but cinches up to a small size if I don't use much of it. The entire bag is also pretty light. I jerry rigged some pockets on the front shoulder straps also for my camera and salt caps. Be careful what you put in a pack. You need to put everything in it that you plan to run with before you actually run, and try it out around the house. Many typically put in more that would carry for long and end up dumping most of it soon after a run starts. If you have extra space, you don't have to use it. You could load it with rocks to carry back home while you run.
(6) COST Prices are all over the place. This can be a very expensive experiment. I suggest borrowing somebody (anybody) else's system for a trail run before buying one. Even swap with somebody you are running with just to get the feel of it.
(6) MY TAKE: I don't care for waist packs. My stomach has enough to deal with just running long distance without putting that kind of pressure on it. I like hand bottles the best but they are only good for short distances, and at night... I need my hands for lights and such. My primary distance hydration-system is a super lightweight Camelbac Rogue. It has a small pocket for keys and pills. It's made for a 70 oz bladder but I have managed to cram a full 100 oz bladder into it. My extra-long (Hardrock) water system is the Cloudwalker. It can hold more water than I will ever use and it has enough capacity for my rain gear, extra food, and all the rocks I want to carry. Both systems have excellent shoulder harnesses that are very comfortable on my shoulders and neither one rides up into my neck. I have removed the waist and chest straps from both of them and only use the shoulder straps. I would like to find something that has pockets up front, but refuse to wear a hydration vest. No air flow! Additional info is at Kevin Sayer's Ultraresources

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