wikiHow to Disinfect Drinking Water in the Wilderness

Three Methods:BackpackingLostUsing the Sun

Usually if you're in this situation you're either on a backpacking trip, or lost. This will tell you what to do in either situation.

Method 1

  1. 1
    Pack the proper water purifying equipment and chemicals. If you're backpacking you should have a high quality pump with a filter, and/or purifying tablets.
  2. 2
    Immerse the end of the pump where water flows in in the clearest portion of the water source that you can see. Deeper areas are preferable since it will be easier to draw out water.
  3. 3
    Pump until your water container is full.
  4. 4
    Drop in the amount of purification tablets needed to purify your water. It should say on the package how many tablets to use per liter.
  5. 5
    Bleed the threads. Once the tablets have dissolved, bleed the threads. Turn your water bottle upside down with the lid on and carefully loosen the cap until a little bit of water leaks out. This will flush the threads of the bottle with the water that has purification chemicals in it, thereby cleaning the threads which often harbor bacteria.
  6. 6
    Wait for a little now. Most tablets say to wait for 30 minutes before drinking the purified water, but check carefully to see what the specified waiting period is for your tablets. Even though it may not seem like it, this is critical. One backpacking guide once said "If you don't wait for the tablets to wash your bottle out, they'll wash you out."
    • After waiting for the specified amount of time, the water should be safe to drink.

Method 2

  1. 1
    Find flowing water if at all possible. It is possible to sterilize still water, but flowing water is usually much cleaner.
  2. 2
    Pre-filter the water through cloth. Take a tightly woven piece of cloth such as a bandana or shirt and group the corners together, forming a bag. Scoop this bag through the water and position it over your water container. The cloth will act as a primitive filter, but will only filter out particles about the size of what you can see.
  3. 3
    Start the fire. Since you may not have tablets when you're lost boil the water to make it drinkable.
  4. 4
    Heat the water until it reaches a rolling boil. Leave the water at a rolling boil for ten minutes.
    • Since your only water container will probably be your water bottle you'll have to unscrew the lid so it doesn't explode from the steam pressure.
    • You should also suspend the bottle so that its bottom is a few inches above the flames. Hopefully, this will keep the bottle from completely melting.
  5. 5
    After ten minutes the water should be safe to drink.

Method 3
Using the Sun

It may sound like a hoax, but the UV radiation given off by the sun can kill bacteria and parasites in the water, but it is not enough to make water potable (drinkable). You will still need to filter and boil or treat your water.

  1. 1
    Fill a clear plastic bottle with water and remove the label.
  2. 2
    Let the water sit in the sun for at least six to eight hours on a 100% sunny day, and 24-48 hours on cloudy days. The UV rays will kill the microorganisms, leaving the water safe to drink.


  • 1 tsp per gallon of water will kill most bacteria. The water should be filtered through several layers of cloth first. A coarse cloth on top, and gradually finer cloths underneath. The water will run cleaner at the bottom, but not clear.
  • It is highly recommended that you use metal water bottles, even though they're a little heavier than the plastic ones. They're more durable and easier to clean since sugars that bacteria feed on don't stick as easily. It's also easier to boil water in them.
  • If you have any doubts, or if the water is smelly after filtering, you might want to boil it just in case.
  • It is best that you use a multi-step process if the water has a lot of debris or seems to be very stagnant, such as in a swamp. You should have a small bottle of a chlorine bleach with you, anyway. 1/4 cup to 5 gallons (18.9 L) of water will sanitize your drinking cups and dishes, so keep that aside for washing.
  • If you're just camping always try to bring 100% safe drinking water beforehand. even if you follow the steps above it's better to be safe than sorry.
  • Add the bleach drops or sanitizing drops and wait one hour.


  • When I go on a hiking trip they tell you to always filter your water at least two different ways, unless you boil water, which you can do only once (although you'll want to at least filter to get rid of any large particles).
  • ALL streams in America carry the diarrhea-causing bacteria known as Giardia, fortunately Giardia can be removed by most pump filters (but not cloth), and it will be killed by boiling water and purification tablets.
  • I've seen some hikers use UV lights such as SteriPENs to disinfect water. If the water were cloudy or icy the light may not pass through the water as efficiently and thus won't kill all of the bacteria and viruses.

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