Very true, Jim. But as I said, you can see water is boiling but that won't tell you if chemicals in it will kill you or not. The big risk there would be urban water after a disaster where petroleum or other chemicals could pollute the water.
With a filter I surely wouldn't rely on one that had been stored for 10 years! But that's just me.
Agreed. In an urban emergency setting, there are a lot of potential contaminants that a backpacking filter (or boiling or chemical treatment) just aren't going to touch. For my situation, I live close to a creek that can be drunk from without treatment, and I also have 25 gallons of water in 1 gallon bottles. I'd like to have more water, but I'm in an apartment, and that apartment has no garage and not a whole lot of storage.
Re the backpacking filter, it's actually a "user" filter not an "emergency" filter. In other words it hasn't been stored in a box somewhere; it's been out on the trail with me. I truly wish there were a way to verify its functioning. Even right out of the box, there's no way to tell if a filter works.
I like using a filter (as opposed to boiling or chem treatment) since I think the taste of unchlorinated water is such a treat compared to tap water at home. I detest the taste of iodine treated water, and the smell is even worse. Chlorine dioxide is a little better but still nasty, and I hate having to wait for the treatment to take effect when I'm thirsty. Boiling requires a lot of time, and who the heck wants hot drinking water on a 95F degree day. Because of all that, I really wish there were a way to verify a filter's function.
HJ