4 Ways to Purify Water for Drinking, Cooking, and Sanitation

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The best techniques for purifying water so it’s safe to drink
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Purifying water is a must-have skill, whether you’re going camping or practicing emergency preparedness. There are multiple ways to do it, each with its own benefits and drawbacks. In this guide, we'll teach you a few basic techniques for purifying water for drinking, cooking, and sanitation. We’ll explain how to remove particulates from cloudy water and store purified water so that it’s safe to drink for several months. To help, we spoke with survival experts Ky Furneaux and Anthony Porter to help ensure you and your loved ones have drinkable water no matter what happens.

How to Clean and Purify Water to Make It Drinkable

  • Boil water for 1-3 minutes to kill pathogens before drinking it.
  • Mix 6-8 drops of bleach per gallon (2 drops per liter) of water, then let it stand for 30 minutes before drinking it.
  • To filter particles out of water, attach a portable camping water filter to a bottle, then squeeze the bottle to pass the water through the filter.
Method 1
Method 1 of 4:

Boiling Water for Drinking

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  1. Do this for cloudy water from a lake, stream, well, or drinking source in an emergency. Collect the water in a container, then place your filter over a second container and pour the water through the filter. This removes particulates like soil, sticks, insects, and other large items from the water. [1]
    • If you only have one container for water, hold your filter over the container, then dip the container into your water source. Allow the water to pass through the filter as it fills the container.
    • You can skip this step if you are purifying clear water from a faucet or similar water source.
  2. Watermark wikiHow to Purify Water
    Furneaux explains, “There is a popular myth that suggests that water needs to be boiled for an extended length of time to make sure it is safe to drink. The truth is that all of the toxic parasites, viruses and bacteria that exist in groundwater are destroyed at temperatures of 70C (158F) degrees or less. Since water boils at 100C (212F) degrees, all dangerous pathogens are completely destroyed by the time water reaches a rolling boil. One minute is more than enough time.”
    • If your elevation is below 5,000 feet (1,000 meters), such as on a mountain or region like Colorado, boil your water for at least 3 minutes. [2] This is necessary because water boils at a lower temperature at higher elevations. [3]
    • Boiling does not remove other contaminants like salts, metals, fuel, toxic chemicals, and radioactive materials. Use bottled water if the water in your region contains these contaminants.
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  3. Watermark wikiHow to Purify Water
    Use clean plastic bottles or jugs with lids. Store your water in a cool place (50°F –70°F or 10°C –21°C), away from direct sunlight and toxic substances like gasoline or pesticides. Replace your water every six months. [4]
    • Store at least 1 gallon of water per person for drinking and washing.
    • Store extra water for pregnant people, pets, or in hot climates such as deserts. [5]
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Method 2
Method 2 of 4:

Disinfecting Water with Chlorine Bleach

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  1. Choose bleach that contains 6% or 8.25% of sodium hypochlorite—you can find this information on the product label under “Active Ingredients”. Make sure the product label contains instructions for water purification. [6]
    • Do not use unscented or color-safe bleach, or bleach with added cleaning chemicals. These cannot be used for purifying water.
    • You can also purify water with iodine or chlorine dioxide tablets. However, the amounts needed vary between manufacturers, and iodine can be harmful to pregnant people or folks with thyroid problems.
  2. Watermark wikiHow to Purify Water
    Add at least 1 liter (0.26 gallons) of water, or fill the container completely if it holds a specific quantity, like a 1-gallon (3.8 L) jug. If your water is cloudy, filter it first using a cloth, shirt, or coffee filter. This will remove particulates like dirt and insects. [7]
    • You can also allow cloudy water to settle in the container, then filter the top layer of clear water through.
  3. Watermark wikiHow to Purify Water
    The exact number of drops depends on the amount of water in your container and the concentration of sodium hypochlorite in your bleach. Double-check the “Active Ingredients” section of the product label on your bleach to determine if the concentration is 6% or 8.25%, then follow the instructions below: [8]
    • If using 6% bleach, add 8 drops of bleach per 1 gallon of water (or 2 drops per liter of water). If you don’t have an eyedropper, add ⅛ tsp. of bleach per 1 gallon of water (or 0.15 mL of bleach per liter of water).
    • If using 8.25% bleach, add 6 drops of bleach per 1 gallon of water (or 2 drops per liter of water). If you don’t have an eyedropper, add a little less than ⅛ tsp. of bleach per 1 gallon of water (about 0.1 mL of bleach per liter of water).
  4. Watermark wikiHow to Purify Water
    After 30 minutes, the water should have a slight chlorine smell. If it doesn’t, add the same quantity of bleach again, mix it in, and let the water sit for another 15 minutes. The water will be safe to drink. [9]
    • Bleach cannot remove salts, metals, toxic chemicals, and other pollutants from water. Stick with bottled water if your water source has been contaminated with pollutants.
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Method 3
Method 3 of 4:

Filtering Water to Remove Particles

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  1. Buy a water filter that can be screwed onto a soda bottle. Make sure the filter has an “absolute pore size” of 1 micron or less. Opt for a water filtration kit designed for camping, since these are lightweight and easy to use. You can buy a water filtration kit online or from a local camping supply shop. [10]
    • A lot of these filters can be attached directly to water bottles. Furneaux recommends the LifeStraw line of products.
    • Make sure your filter specifies an “absolute” pore size of 1 micron or less. Filters labeled “1 micron” or “nominal pore size of 1 micron” are not sufficient. [11]
    • An “absolute” pore size of 1 micron means that all pores in the filter (the passages where water passes through) are 1 micron in size or smaller. 1 micron = 1/25,000th of 1 inch (1/10,000th of 1 cm). [12]
    • These filters remove particulates and microscopic parasites, but they may not remove bacteria and viruses.
  2. Avoid dark, muddy water, but don’t worry if the water is a little cloudy or contains particulates. [13]
    • If your kit comes with a bag for collecting water, use it to collect unfiltered water.
  3. Place the filter on the top of the bottle, then screw it on as if it were a bottle cap. Screw it tightly and turn the bottle over to make sure no water leaks from behind the filter. Screw it tighter as needed until the leaking stops. [14]
    • For kits with water bags, attach the filter directly to the bag.
  4. Avoid squeezing too hard to prevent the water from leaking from behind the filter. The water will squirt from the nozzle at the tip of the filter. This water is now purified and safe to drink. [15]
    • You can also hold the bottle upside down to allow the water to sink through the filter via gravity.
    • If using a water bag, squeeze and roll the bag to move water through the filter.
  5. Fill a jug, water bladder, or separate water bottle with purified water. Or sip from the filter’s nozzle if you’re thirsty enough. Once the bottle attached to the filter is empty, remove the filter and let it dry, or collect more water for purification. [16]
    • Make sure to use separate containers for collecting and storing water. Otherwise, you may re-contaminate your filtered water.
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Method 4
Method 4 of 4:

Using an Ultraviolet (UV) Water Purifier to Kill Pathogens

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  1. Buy a UV “probe” water purifier that can be dipped into water, allowing the UV light to kill any pathogens. You can buy portable UV water purifiers online for $120. Note that these are battery-powered and require regular charging. [17]
    • Homeowners can also install household UV purification systems. These connect directly to your plumbing, supplying you with potable water 24/7.
    EXPERT TIP

    Ky Furneaux

    Survival and Outdoors Expert
    Ky Furneaux is a survival expert, outdoor guide, and professional stuntwoman based in Australia. She’s been featured in over 100 films and TV productions, and has hosted, produced, and participated in some of the most extreme TV survival shows including MTV’s Made and Discovery’s Naked and Afraid. She has authored 5 survival books, including "The Superwoman’s Survival Guide" and "Survive: The All-In-One Guide to Staying Alive in Extreme Conditions", with the goal of sharing her knowledge of survival techniques with others. As an accomplished stuntwoman, she won a Taurus Award in 2012 for Best Female Stunt Performer and has doubled stars like Jennifer Garner, Anne Hathaway, Jaime Alexander, and Sharon Stone.
    Ky Furneaux
    Survival and Outdoors Expert

    While UV disinfection is a powerful tool in water treatment, it is not universally effective against all pathogens. Water quality, UV dose, and the microorganisms in the water will all impact the efficacy here. You likely want to pair UV disinfection with filtration and chemical disinfection if you aren’t sure about the water source.

  2. Choose clear water with few or no particulates. Avoid adding more than 0.5 L (.13 gallons) of water, since your UV device can only purify a small volume of water at a time. [18]
    • Some UV purifiers allow you to specify a quantity of water to be purified. Check your device’s settings and adjust the quantity of water as needed.
    • Filter cloudy water with a cloth or coffee filter before adding it to the bottle. Cloudy water blocks UV light, preventing purification.
  3. If your device has a timer, leave it in the water until it turns off. Otherwise, leave it for one minute. Avoid removing the device too early or you’ll have to start the purification cycle over again. The water is safe to drink after one minute, or after the device automatically turns off. [19]
    • As with most water sanitation methods, UV purification can’t remove toxins or metals from your water. Opt for bottled water if you suspect your water source is contaminated.
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Expert Q&A

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  • Question
    Do I need to purify rainwater if it's from a forest with no pollution?
    Anthony Porter
    Outdoorsman and Survival Expert
    Anthony Porter is a nature educator, archer, and outdoorsman based in South Lake Tahoe, California. He is an Outdoor Survival expert, and educates millions around the world through his social media presence as “Outdoor Anthony”. His videos have turned him into a viral sensation on TikTok & Instagram, where he has over 400k followers. He is the current Communications Director of the Tahoe Rim Trail Association, promoting wildlife stewardship and preservation on print media, TV, and radio. Anthony has also showcased his outdoor prowess as a recurring yearly TV athlete as NBC's the Archery Ninja on American Ninja Warrior. He is also the producer, editor and Host of the Orangutan Podcast, discussing rainforest conservation initiatives with Dr. Gary Shapiro, famous for teaching orangutans symbolic sign language. As a professional educator for the better part of a decade, Anthony has explored 20 countries, and has taught people of all ages across the United States. He received a Bachelor’s degree in Parks and Recreation Management from Northern Arizona University, and earned an MBA from Cal Poly Pomona with a concentration in sustainable Marketing, and is always looking to dive right into the next adventure.
    Anthony Porter
    Outdoorsman and Survival Expert
    Expert Answer
    Even if you collect rainwater from a forest or a place with zero and no pollution, it's still a good idea to purify the water before drinking it. While rainwater collected from a forest area with no pollution might be much safer than water collected in a city, there’s still a chance it could carry contaminants like bacteria, dirt, or particles from leaves and branches. These small impurities can make you sick if the water isn’t treated. To be on the safer side, always filter and purify rainwater before drinking it, no matter where you collect it.
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      References

      1. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      2. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      3. ↑ https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2144&context=extension_curall
      4. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      5. ↑ https://www.cdc.gov/water-emergency/about/how-to-create-and-store-an-emergency-water-supply.html
      6. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      7. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      8. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      9. ↑ https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water
      1. ↑ https://www.cdc.gov/healthywater/drinking/home-water-treatment/water-filters.html
      2. ↑ https://www.cdc.gov/healthywater/drinking/home-water-treatment/water-filters.html
      3. ↑ https://www.unitconverters.net/length/micron-to-inch.htm
      4. ↑ https://youtu.be/iUsdx0UC2uU?t=66
      5. ↑ https://youtu.be/iUsdx0UC2uU?t=68
      6. ↑ https://youtu.be/iUsdx0UC2uU?t=59
      7. ↑ https://youtu.be/iUsdx0UC2uU?t=54
      8. ↑ https://youtu.be/tD-Ya2SQk3k?t=340
      9. ↑ https://youtu.be/_g9quh6T-y0?t=45
      10. ↑ https://youtu.be/_g9quh6T-y0?t=55

      About This Article

      Article Summary X

      To purify water, start by straining out large particulates like pebbles, insects, or plant matter. Pour the water from one container to another, passing it through a mesh strainer lined with a dish towel. If you don’t have a strainer, pour the water into a container and let it settle for 1-2 hours. Skin lightweight particles off the surface of the water, then gently pour the water into a clean bowl or jar. Stop pouring before you get to the bottom so the heavier sediment will be left behind. Keep in mind that these methods will not remove pathogens or heavy metals from the water. Read on to learn how to purify water using chemicals!

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