LifeStraws are great, but they’re directly water-source to mouth. You can’t use them to purify water to keep in a canteen for later, for mixing powdered drinks, to pour over a wound to clean it, etc.
The Sawyer Mini add flexibility, without having to MacGyver it…
Be prepared! That’s the boy scout’s marching song,
Be prepared! As through life you march along.
Be prepared to hold your liquor pretty well,
Don’t write naughty words on walls if you can’t spell.
I don’t make a whole fetish out of it, but when I transit on foot, I have in my backpack:
3-4 mini light sticks
a lithium cell keychain flashlight
an emergency rain poncho
a survival blanket
a 1" blade knife
a few 9m spools of dental floss (free from dentist visits)
a couple tealights and waterproof matches
a couple cereal bars
earpods to make the FM radio on my phone work
phone charge battery packs
If I’m on a walk/hike, I add a first aid kit, tensor bandage, water bottle or 2L hydration pack.
Have I ever used any of it, beside the water? Hmm. I think I gave a rain poncho to a stranger during a summer deluge once. The knife is used to open those ridiculous sealed plastic packages.
The Sawyer is a great little filter, more versatile than the Lifestraw. Only a few things to watch out for:
Cross contamination. Follow the backflush instructions, so you don’t get nasties growing in the outlet tube. I use chlorine-dioxide treated water for this; doing a chemical treatment every day or two also helps guard against biofilm formation in my water containers.
Freezing. If it’s been allowed to freeze, the ceramic filter element will crack and must be discarded.
Obstruction. A clogged filter does nobody any good, so prefilter turbid water through a coffee filter or bandana.
It doesn’t protect against viruses, but in North America the worst waterborne virus you’re going to get is norovirus, which willl ruin your trip but is seldom life-threatening in a healthy adult. Elsewhere, worry about poilo, hepatitis A, and various hemorrhagic fevers, and either combine filtration with chorination, or else boil the water.
It doesn’t work against chemical contamination. Then again, there are no methods that work universally against that, so the best advice is not to drink downstream of humans.
Except for freezing, all of the risks I list are manageable, so I bring a Sawyer in three seasons, keeping it inside my jacket or sleeping bag. In real winter, I likely can’t find any water that isn’t frozen, and if I’m going to melt it, I might as well boil it.
Lose the light sticks and carry a real headlamp with lithium batteries - near indefinite shelf live, high energy-to-weight, and you can actually see by it.
Waterproof matches aren’t. Lose them and carry a Vaseline-impregnated cotton ball (in an Altoids tin) and a fire steel. (Also, I can’t strike a match or work a mini-Bic when I’m shivering, but I have enough coordination to spark a fire steel. I learnt that in a real-life urgent situation.)
What’s the dental floss for, if you don’t carry a needle? I guess you can clean your teeth with it. Although I once had a brown trout take an improvised fly (a bit of feather that leaked from a down sleeping bag, tied on a safety pin, dangled on a length of dental floss). Didn’t have any good way to set the hook or land him, so just played him until he spit it out again.
With the exception of the PLB, I think I’ve used all my emergency equipment at least once.
For me, the drawback that makes iodine a non-starter is that it’s ineffective against Giardia, Cryptosporidium, and Entamoeba histolytica. I hike in beaver country. Beaver fever is no fun, and neither is dysentery. For chemical treatment I use chlorine dioxide - the two-part drops, which keep, not the tablets, which spoil.
Used this in Madagascar. Went back to Katadyn tablets, because I found them much easier to use. I dropped the drops (DOH!) several times and destroyed one tent floor like this. Not to speak of discoloration of trousers, which didn’t really matter.
ETA: I borrowed a Katadyn pump filter I could screw directly on locally available plastic bottles for several trips in West Africa. Combination of ceramic filter and activated carbon to reduce potential input of organic and metal contamination. Added Katadyn tablets for being able to keep the pumped bottles longer.
If you don’t have any of that, in the tropics, you can at least try solar disinfection. I suggest to paint one half of the bottle with white paint (paint containing TiO2 would be especially good, depending on the source it could even be used to coat the inside of half of the bottle to add additional efficiency).
