• Boiling water for 1 to 3 minutes will will purify it sufficiently.
• It will kill off the vast majority of organisms living in the water. It also removes some chemicals by vaporizing them. However, be aware that boiling the water will not remove solids, metals, or minerals. Also be aware that the boiling point of water decreases with altitude, so you will not get the same purification effect on a mountain top as you would on a coastal plain. You can boil the water longer or use a pressure cooker to offset the lower temperature.

Use purification tablets or drops. You can purchase these drops or tablets at sporting goods and adventure stores. Keep in mind that this is not the best tasting method, but protection from bacteria is worth a bitter taste in your mouth.^[5]

• Iodine tablets are the most commonly sold purifying tablets, but you can also use chlorine tablets with the same result. These tablets are most effective when the water you are purifying is 68 degrees F (21 degrees C) or higher. These chemical tablets will kill bacteria living in your water. These tablets are most often used by campers in the wilderness.
• Pregnant women, women over 50, and people with thyroid problems or taking Lithium should consult with a doctor before using iodine tablets.

Strain the water if it has large particles floating around in it. You can do this by pouring the water through a cloth and into the bottle or container that you will be purifying your water in. The cloth acts as a strainer that removes the particles floating in the water.

Place the tablets in the water. If your tablets or drops came with instructions, follow these now. In general, you will want to use one tablet for each quart or liter of water you wish to purify. Be aware that these tablets generally have an expiration date. If you use them after this date, they are much less likely to be effective. Always check the bottle before using these tablets.

Mix the tablets into the water until they dissolve. They must be completely dissolved so that they can mix most effectively with the water you are purifying. Wait 30 minutes before drinking the water, as the tablets need that time to effectively kill any bacteria in the water.

• You should also be aware that tablets are generally less effective in water that is very cold. If the water is 40 degrees F (4 degrees C), you should wait at least an hour after the tablets have dissolved before drinking the water. You can place the water in the sun to warm it up before using the tablets if you have the time to do so.
• To lessen the strange taste the tablets give the water, add flavoring to the water (if it is available to you.) Powdered lemonade mixes or a pinch of salt will mask the tablet flavor.

Use a pump purifier. You can use these types of purifiers in conjunction with a canteen or water bottle when out in the wilderness. These pumps are generally hand held and made out of a synthetic or ceramic cartridge. Most filters have two separate hoses, one for clean water, the other for dirty water. On the hose that pumps the dirty creek or lake water, you may find a foam flotation device that keeps the hose from sinking to the bottom and sucking up the silty bottom water. The pump will have a plunger or lever that can be pulled and pushed so that water is sucked up, run through a series of filters within the plunge, and then pumped out and into your water bottle.

• There are also pump purifiers that attach to the sink in your kitchen. These pumps can be bought at any home improvement store and are based on the same concept as the hand pump (though attaching it to your sink saves you the time of actually having to pump the water.)

Buy a water bottle with a built in purifier. You can now buy water bottles that have their own filters already built in. These work much like the pumps in that they run the water through a filter before dispensing the water into the bottle.

Use an ultraviolet purifier. These purifiers are very easy to use– you simply stick the pen of the lamp into the water, wait for the light on the side of the pen to turn green, and then stir the pen around in the water until the light turns off. The UV rays kill any bacteria living in the water so that your water becomes safe to drink.

• Keep in mind that this purifier doesn’t filter out the now deceased bacteria, but despite their continued presence in your water, they are not dangerous anymore.

Try out a gravity fed purifier. These are filters like the ones used by Brita and PUR. As the name suggests, these filters use gravity to pull the dirty water through a filter and into the reservoir that contains clean water. To use this purifier, all you have to do is pour unpurified water into the dirty water section, and wait until all of the water has run through the filter. Often, these filters will have two sections–one for dirty water, and the other for clean.

• These filters are best used at home or at a campsite as they are generally pretty large and would be a pain to tote around in the wilderness.

Form a cone out of a strip of bark. Birch bark, or a bark similar to it, is best for creating this filtering system because it is flexible but will keep its shape. Keep in mind that this method will not fully purify the water, but it will reduce the amount of microbes in the water. This method should only be used in extreme emergencies.

• If you are having a hard time keeping your bark in the shape of a cone, you could try tying a piece of rope or a durable type of grass around it to keep its shape.

Layer the cone. Wildwood Survival suggests layering the cone with sand, charcoal, grass, and gravel (or small rocks.) Charcoal is especially good for removing bacteria. If you had fire, crush up some of the burnt pieces of wood.

Pour the water through the cone and into a container. Do this several times to increase the amount of purification that occurs. Again, this method does not guarantee purification, but it will remove a good deal of the contaminants in the water.