I have used water filters (three different kinds), iodine and Aqua Mira to treat water. Aqua Mira is my first choice, iodine second. Never again will I carry a filter on the AT. They clog too quickly. And when they do, they pump very slowly -- so slowly it might take 10 minutes to filter a quart. It's nothing for me to load up on five quarts when I stop for the night, so there would be 50 minutes pumping a filter.
Aqua Mira comes in two small bottles that treat 30 gallons total. They come with a small cup that fits over the top of one of the bottles. You mix seven drops from one bottle and seven from the other in the small cup. When a couple of minutes later it turns yellowish and bubbly, and has a faint bleach-like smell, you put it in a quart of water. Wait 20 minutes and you can drink the water. The bleach-like odor (I am told) is not really bleach, but the same kind of gas water treatment plants use. I hike with two of the little cups (one saved from a previous package), to do two quarts at a time.
Iodine will give water a slight taste (which I don't mind at all). Aqua Mira won't. One way to get iodine is go to a drugstore and ask the pharmacist for a bottle. You might have to sign for it, I don't recall. The iodine is 2 percent tincture. Put 2 drops in a quart, wait 30 minutes and you can drink it. If the water is cold or cloudy, I might use 3 or 4 drops. One iodine water-treatment product is called Polar Pure. A bottle weighs 4 ounces and it uses iodine crystals. The crystals, which can't be poured from the bottle, put the iodine in water that you keep adding to the bottle. After it stands in the bottle a while, you can use 1 or 2 capfuls to treat a quart. You could walk the entire AT and treat all your water with a single bottle of Polar Pure.
Water from a spring often is as clear as water from a faucet. Water from streams often has small bits of stuff in it. I bought some reusable sort of paper towel things at a supermarket which are lightly woven nylon cloth. I use those to strain stream water. I always carry a little funnel (the kind sold to put fuel in Coleman stoves) and use it only to hold the cloth that strains water. It would be a good plan to carry at least one coffee filter. On the rare day you'd have to dig a hole to collect muddy water, the coffee filter would be better than a bandanna. Some hikers don't filter their water at all. I once read an article that claimed these people don't get sick any more than those who treat or filter water. I always treat water, but I'd trust untreated spring water more than that from a stream. The rare polluted stream you will find will be greenish or yellow and full of what looks like soap suds; nobody in their right mind would try to drink from it.
I have read that in New England, one must sometimes get water from a pond. I hope they are cleaner than the ponds I have seen in Virginia, which I wouldn't drink from.
One more good water source can be puddles. Two or three times I have found a big puddle of clear water.
I always carry a small white empty plastic butter dish. I use it to scoop water from streams. Because it's white, I can tell at a glance if I scooped up too much sand, dead bugs, bits of dead leaves, etc.
About Aqua Mira:http://www.aquamira.com/consumer/aquamira-water-treatment-drops/
About Polar Pure:http://www.polarequipment.com/
After trying canteens, Nalgene bottles, etc. I now use one-quart Gatorade bottles (Powerade bottles also are fine) and a two-liter Platypus water bag. I might carry one small Nalgene bottle only because it has ounces marked on the side. The Gator/Powerade bottles are extremely light and very strong. So is the Platypus. It looks flimsy, but I've used the same one on my trips and it has never leaked. It has a small opening, so a funnel is a real help in filling it up. I always wear a small fanny pack (to hold a camera, etc.) and it has a spot that holds the small Nalgene for drinking while walking. I have never used (and never will) one of the water bags that lets you drink from a tube.
Trail guides (books)
There are three kinds of trail guides that I know of.
1 - The Appalachian Trail Conservancy (the official managers and overseers of the AT) publishes 11 trail guides, each covering a different section of the trail. These guides go into great detail. They identify trail features such as shelters, mountain peaks, crossroads, water sources, etc. etc., sometimes listing as many as 5 or 6 such features for every mile of trail. These descriptions tell you how far apart everything is in miles. The books also tell you where to find parking lots along the trail. They also contain pages upon pages of the history and geology of each region. For a section hiker like me, who parks his car and hikes a week or two at a time, these guides are excellent. Each one weighs 5 or 6 ounces. I either photocopy or cut out the pages showing the trail descriptions, and leave the rest at home. The ATC also sells maps. It varies, but maps usually cover 50 to 75 miles each. I always carry a map, mainly because they contain "profiles" that show you the height of all the hills you have to go up and down.
Find the ATC stuff at:Guides and Maps
2 - A guy named Dan "Wingfoot" Bruce prints "The Thru-Hiker's Handbook." This weighs 6 ounces and covers the entire AT. This is a great book. A thru-hiker would do fine carrying this book and nothing else. It lists trail features in a more concise style than the ATC books, but still lists up to 5 features per mile. The elevation of each feature is listed. This means you can get a rough idea of all the hills by comparing the elevations. The book also has a big section telling about all the towns close to the AT. This tells where to find the stores, motels, restaurants, post offices, etc. -- the kinds of places thru-hikers need to know about. He puts out a new edition every year and sells it fromwww.trailplace.com.
The main advantage the ATC books have over Dan's is the ATC books list parking lots and are more specific on finding the water sites.
3 - Appalachian Trail Thru-Hikers' Companion. This weighs 8 ounces and is printed every year by the Appalachian Long Distance Hikers Association. It describes the towns, stores etc. along the trail in a little more detail than Dan's book, but lacks the trail descriptions. It mainly describes the shelters and little else. Dan's book a far better choice if you're only going to carry one of them.
There are hundreds of shelters along the AT, most of them are between 7 and 10 miles apart. Most are wooden structures (with wooden floors) with an open front. Some have stone walls. The smallest I have seen would sleep about four and the biggest about 15. Almost all shelters have a fireplace, a spring or stream, a picnic table, an outhouse and places to pitch tents. One I visited has a cold water outdoor shower. Some hikers carry no tent, so they depend on finding a spot in a shelter. I don't like sleeping in them, and usually will do it only when exhausted to the point of collapse and I find no one else there. Even so, I spend most nights at shelters, but inside my tent. This is because much of the AT is so steep and rocky and screwed up I can't find a flat place to pitch a tent anywhere else, and because there is water at shelters. (A tent is always warmer than a shelter because a tent keeps you out of the wind.) Maybe for every 5 or 6 shelters I pass, I can find a nice campsite with no shelter.
In Maryland and the Smoky Mountain National Park, you are required to stay at shelters. Elsewhere, I have twice pitched my tent right next to the trail. This is considered bad form, at the least, but it was late and I was miles from a shelter. The outhouses at shelters can stink pretty bad. I always prop the door open with a rock or something, and wait at least a minute before I go in. Each shelter has a trail register or journal, a notebook in which hikers write whatever they feel like writing. I usually attempt to glance at the most recent pages, because if something wacky or weird is happening in the area (e.g., forest fires, fallen bridges, mad bears, alien abductions, murderers on the loose, whatever), somebody might write about it. Most shelters are located close to a road through the woods. These roads might lead to a dirt road, or a highway. Also, some shelters are close to road crossings with parking lots, particularly in the Shenandoah National Park. This means weekend warriors who want to walk only two miles from the car can hog the shelter and stay up half the night making a bunch of racket. Pity the poor worn-out tentless thru-hiker who arrives on a scene like that.
Since rules on camping and shelters vary at different locations, here's the ATC page on the subject:
The animal that makes the most trouble on the AT is the mouse. The little varmints know people bring food to shelters and campsites. If you fail to hang your food bag, they may crawl into your pack and chew through whatever's in their way to reach a snack. They also might run across your face as you sleep in a shelter. Or enter your tent.
One night during a pounding nonstop rain, a mouse entered my friend's tent, crawled to the bottom of his pack and chewed through a couple of sacks and ate some granola. Bears and raccoons also could go after your food, but mice far outnumber the raccoons and bears. I bought a sil nylon bag called a Granite Gear Air Space to carry and hang food. It's waterproof. I use a thin nylon cord about 15 feet long to hang the bag over a tree limb about 10 feet high. I tie a carabiner to one end of the cord so I can toss it over a high limb so I can pull the bag up. Needless to say, this sometimes takes several tries. Most shelters have hanging cords, with each cord passing through a small can. The can is to keep the mice from climbing down the cord. I also have hung food in a plastic garbage bag. Shelters in the Shenadoah National Park (which has a ton of bears) have metal "bear poles" on which to hang food bags.
I have seen maybe 12 or so bears on the AT, mostly in Shenandoah. Most will run as soon as they see you. Some may look at you a few seconds and then go. If one headed toward me, I'd start yelling and throwing rocks at him. Several times I have approached a small bear in a tree, not knowing he was there, and the bear waited until I got close to have a panic attack and decide he had to run immediately. So with me about 40 feet away, he slides down the tree in a shower of leaves and branches, with his big butt hitting the ground with a thud. At several other spots I have seen sticks and leaves on the trail, where another bear had made an emergency getaway. You are most likely to see this in Shenandoah.
I once carried a big can of bear spray. (Pepper spray that will shoot about 15 feet.) At gun stores, you should be able to find the civilian version of the pepper spray police use. I have a can called Fox Five Point Three. Much smaller than bear spray. I would think having this stuff on hand would be most valuable in case some bear wandered into my campsite and refused to leave. I was in my sleeping bag one morning and could hear a bear snorting and padding around just outside the tent. I snapped, "Beat it!" He instantly stopped snorting and slinked off. This was in Shenandoah NP.
There are rattlesnakes and copperheads on the AT. Both poisonous, of course. The rattlesnakes make noise and let you know they are there. I have seen one, about 3 feet long. Haven't seen a copperhead.
The Granite Gear Air Space (I use the big one):Air Zippsack