For the last 3 years, I have been using a WAPI (WAter Pasteurization Indicator) to make water potable. A WAPI is simply a piece of wax that melts at 149 degrees F., sealed in a polycarbonate tube that can be lowered into a pot of water. When the wax melts, the water temperature is 149 degrees (obviously) and 5 minutes at 149 degrees is enough to kill any life forms that could hurt you. The WAPI is then removed from the pot so the wax can harden. A WAPI can be re-used until the tube breaks or leaks -- which I have not seen occur yet.

If you can pasteurize milk, why not pasteurize water? Milk is pasteurized by bring it up to 160 degrees for 15 seconds, from what I've been able to find. The "Pasteurize" idea dates to Louis Pasteur, who came up with the idea that germs could cause disease. Anything that is pasteurized has its unhealthy germs killed.

For years I have seen it written that water must be BOILED, for one minute, for 5 minutes, for 10 minutes, to make water drinkable. The only problem with this rule is that it is untrue. 149 degrees for 5 minutes, or 160 degrees for 1 minute, will do the same thing.

There are three good reasons to use a WAPI. First, it takes much less fuel to raise water temperature to 149 degrees than it does to 212 degrees. Second, a WAPI is foolproof in operation, not subject to reading errors like a thermometer. The wax melts or it doesn't. Third, water boils at lower temperatures at the lower atmospheric pressures of higher elevations, but you can always get it to 149 degrees.

I haven't figured out how to post a picture, so here's a written description of a WAPI. Imagine a transparent polycarbonate tube 1-1/2" long and 3/8" outside diameter. Plug one end with a piece of polycarbonate rod 3/8" long and 1/4" outside diameter. Add a piece of 149-degree wax. Plug the other end of the tube with a similar plug. Drill small holes horizontally through the ends of the plugs. Add fishline through the holes with stainless steel washers on each end. To use, pull the fishline so there's a washer by the end of the WAPI, and sink the WAPI/washer combo in your heating pot. Pull it out to check if the wax has melted. That's all.

Obviously a WAPI does NOT remove chemicals, etc., from water. It's just a thermometer.

As an LDS Scoutmaster, I have had Scouts assemble WAPIs, which we sell for $6 each. I know that the WAPIs are almost bulletproof because one of my 11-year-old Scouts was unable to break one. He has a Dennis-the-Menace reputation of being able to break anything. He's done a good job with fiberglass tent poles, tent zippers, meltable plastic containers, etc. -- but not with a WAPI.

I am working on WAPIs with stainless steel wire instead of fishline. Campfire heat can warp fishline, but the wire doesn't have that problem. Still field testing them, and about 3 months behind because of a burn ban here against open fires.

I think this is the neatest new survival idea in years! If anyone is interested in WAPIs for their BOB, emergency kit, etc., PM me.