How foul was the worst looking water that you ever drank? We all want to be choosy when procuring water in the wild, but you rarely see crystal clear streams in environs where water is scarce. Sometimes, the only fresh water available doesn’t look very fresh at all.

I’ve had to disinfect (and subsequently chug) some green-looking water from a ditch in a coastal plains region. I know other folks who have had to suck down water worse than that. In situations like those, purification overkill seemed justified, leading me to come up with a concept for “double disinfection.”

While boiling is my primary bug-killing technique, there are times when it’s impractical or impossible to boil all of your drinking water. Commercial water filters are my next line of defense, but they can leave me wondering if any viruses or bacteria weaseled their way through the filter element. This is when I double down on my methods to destroy any disease-causing pathogens, by following this three-step procedure.

1. “Rough filter” any chunky, slimy, or particle-laden water by pouring it through a cloth filter. This will extend the life of your water filter greatly.

2. Pass the water through a reputable filter with some capacity for microbe destruction. I’m a longtime fan of the Katadyn Pocket Filter, with its silver-infused ceramic filter element. The ceramic screens out big pathogens, while the silver kills the more diminutive bacteria and viruses.

3. Add two drops of household bleach per quart of water, shake aggressively, and let the water sit for one hour. Any mini-microbes that slipped past the filter should be thoroughly fried by the chlorine.

Use this technique with swamp water, if you’re using an aging water filter, or anytime you are feeling a little paranoid about your self-made water supply.

What’s your water purification strategy? Let us hear it in the comments.