Yup, I agree Jon. A lot depends on the area you hike. In many cases, filtering is not the best. Sometimes, it is the only option, too. of the methods you can use, filters and UV treatments are near the top for versatility.
1) Boiling boiling can reduce the amount of water in a pot. This will tend to increase any toxins in the water. And it takes a LOT of energy (fuel.) Since you generally only boil water once or twice per day, it also results in a larger carry weight per day, even if you use a wood fire. Boiling is about the safest from a bio-load standpoint. It will kill anything bad. Note I did not say sterile. There are several microbes/viruses that will survive for a few minutes in boiling water.
2) UV is a radiation that will kill microbes and bacteria. It might not work on some larger parasites (liver flukes, some tape worms) For most water in the US, it works fine, but can be inefective in heavily silted water. It also results in the least carry weight if you hike across a water source or two every 4 hours.
3) chemicals (chlorine, AM drops, iodine, etc) work well, but is inefective against some bugs and needs to be left “working” for 4 hours for maximum effect. It also results in a high carry weight since you need to have treated water to drink and still carry “working” water. Crypto is HARD to kill.
4) Filters tend to be time consuming and are often fiddly to use with multiple hoses. (though the sawyers are fast enough that I can refill two bottles on a single 5min break.) The small water bottles are painful to fill/filter three times for a liter of water. They can be bulky to carry. They tend to plug up with use. and are not very effective against viruses, unless you have a really good filter.
5) Do nothing, and simply drink the water.
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