What if you got caught in a situation where you needed to turn raw water into drinkable water but all you had was an empty plastic bottle? The Survivalist, a blog from Outdoor Life magazine, just published tips in case you ever find yourself in that situation.

The following comes directly from The Survivalist:

DIRECT BOILING
With a bit of wire, you can dangle a plastic water bottle over a fire and usually get it hot enough to boil (or at least pasteurize) the water. Of course, this method leaches all kinds of toxic and nasty tasting chemicals into the water. But in an area with life-threatening pathogens in the water, I’ll take my chances with the plastic toxins.

IN-BOTTLE BOILING
If you can’t put the bottle over the fire, you can put the fire in the bottle—or more correctly, put hot stones in a wide-mouthed bottle of water. Many water bottles developed for the outdoor sports industry are made from impact-resistant and heat-resistant Lexan plastic. While you shouldn’t put your Lexan plastic bottle over a fire to boil water, you can put the heat of a fire inside the bottle using hot stones.

STEP 1: Collect about 2 dozen small stones from a dry location, making sure that each one will fit into the water bottle easily.

STEP 2: Heat the stones in your fire for 30 minutes, and make some wooden tongs to drop small, hot stones in the bottle of water, one at a time.

STEP 3: Use the tongs to replace the stones, one at a time. Each stone will impart heat into the water, which will get it boiling and keep it boiling. Keep one stone at a time in the water, until 10 minutes of boiling have passed.

SOLIDS
If you have a clear plastic bottle, some clear water, and a sunny day, you can use the sun’s light to make your water much safer to drink. Largely advocated for developing countries, solar water disinfection (aka SOLDIS) is gaining traction in the survival-skills crowd; and it’s a great fit for equatorial countries with abundant strong sunlight but few other resources. The most common solar disinfection technique is to expose clear plastic bottles full of questionable water to the sun for a minimum of one day. The sun’s abundant UV light kills or damages almost all biological hazards in the water. There are some problems, though. You need sunny weather (or two days of overcast sky) to reach the maximum effectiveness. You cannot use it in rainy weather. It offers no residual disinfection. It may be less effective against bacterial spores and cyst stages of some parasites. Both the water and the bottle need to be very clear. And finally, it only works with bottles that are 2 liters or smaller. While solar disinfection isn’t 100 percent effective, it’s still a lot better than taking your chances by drinking raw water.

We also have some information on how to prepare water in case of emergency on our Water Emergencies webpage on DrinkTap.org.