Four Easiest Ways to Purify Drinking Water

Spread the love

Written by Travis Noonan

Whether you’re a seasoned prepper or new to the scene, this is practically a law of the universe itself: You need a method for making clean drinking water above and before all else. When disaster strikes – be it a natural event or manmade – conventional sources of clean water disappear. Public infrastructure often fails. Stores get cleaned out. No glass to fill under the tap, no 24-pack to snag at the local grocer.

Panic not: There are four incredibly simple ways to purify any source of water, making it safe to drink – even if it comes from a muddy creek, mosquito-laden pond, storm drain, or the like. Let’s review:

#1. Mechanical Filtration

Water molecules are physically smaller than any known parasite, bacterium, spore, or other organic contaminants. That means you can effectively and safely purify your drinking water with simple filtration: Sort out the “bad stuff” that’s too big to fit and allow pure H2O to pass through.

There are numerous water filter systems available which are portable, lightweight, self-contained, and reusable. This writer frequents many lakes and waterways while he hikes in Utah’s Wasatch and Uinta mountain ranges, and he relies on a Sawyer MINI Filtration System.

How it Works

The process for mechanical water filtration is physically simple: Dirty water is forced through a mesh framework of microscopic fiber tubes, which converge and feed into a drinking straw. These tubes have tiny, open pores measuring 0.1 microns. Bacteria measure 0.2 to 10 microns in length and width, so they can’t pass through the pores. Water molecules, however, are much smaller and pass through without issue. Through the straw comes pure water with no contaminants.


Nano-fiber water filtration requires no prep work or chemicals, and it can be used with virtually any source of water. No container is required, and this method of water purification is also the fastest, considering it’s virtually instant. This also is best for safely drinking from a source of standing or discolored “dirty water” that contains plant and other, larger matter, as all particulates are trapped by the filter. Because the filter pores are 0.1 microns in diameter, 99.9999% of all bacteria and organic causes of disease are captured.


Mechanical filter systems will eventually clog, and the filter media will require replacement. This is especially true if you’re purifying dirty water filled with many particulates. The Sawyer MINI advertises its filters to last for up to 100,000 gallons, but it is strongly recommended one first filter large particles and contaminants with a simple strainer or cheesecloth, to reduce the rate at which the filter clogs.

Some viruses measure less than 0.1 microns, leaving the chance that the filtered water could still harbor infectious disease. To ensure complete purification, additional boiling or the use of iodine is recommended. Other filtration bottles may contain a chemical filter to eliminate viruses, like the GRAYL Ultralight Purifier. For the apartment prepper, a stand-alone home water filter system can be fed with outside sources and will effectively remove viruses, though at a higher cost.

#2. Good Ole’ Boiling

You can’t reinvent the wheel, nor can you find a much better method of purifying your drinking water. Boiling is sufficient to eliminate all bacteria, viruses, protozoa, and all other sources of infectious disease. Even if your boiled water is cloudy, discolored, or unfortunately distasteful, rest assured it’s safe. Although not as convenient as mechanical filtration, boiling water is one of the most effective methods.

How It Works

Boiling water brings its temperature up to 212 degrees (F). This temperature is sufficient for bursting the cell walls and destroying the organic structure of all protozoa, bacteria, and organic pathogens. Viruses are technically not alive nor organic, so they can’t be “killed”. Nonetheless, boiling destroys the DNA contained in the virus, eliminating its ability to infect and replicate.

To ensure complete purification, water must be subjected to a rolling boil (not just simmering) for at least 60 seconds. At altitudes greater than 6,500 feet, water must be boiled for at least 180 seconds.


Boiling large quantities takes time, but this is still the fastest method guaranteed to kill or eliminate 100% of all known causes of infection.


Boiling water requires heat, which may not always be feasible or available. Boiling won’t remove discoloration or particulates, even if the water is safe to drink. Without a large container and fire, oven or stove, boiling is not the most efficient method for purifying large quantities of water to be stored and is better suited for individual consumption.

#3. Chemical purification (Chlorine dioxide/iodine)

When filters and heat aren’t available, modern chemistry is your best choice for safely purifying drinking water, especially in large quantities meant for storage. Chlorine dioxide and iodine are safe-to-consume chemical compounds that effectively eliminate nearly all known pathogens, contaminants, bacteria, and viruses. While others have reported using bleach as a water purifier, these two chemicals are generally safer and easier to use.

They’re also easy to store and carry, requiring a small dose to purify relatively large quantities of untreated water. Both compounds are available as individual tablets and liquid tinctures.

How It Works

Both compounds disinfect water through a chemical reaction, a process that takes 30 minutes to four hours, depending on water temperature. Both are also particularly effective at killing Giardia lamblia (including cysts) and Cryptosporidium – two of the most common infectious parasites found in untreated drinking water.


No prep or pre-filtering of any kind is required. The container in question need not be sterile, as the chemical reaction which occurs kills all pathogens and contaminants. Ideally, water should still be strained or pre-filtered to remove large particles. When used correctly, neither chemical induces poor taste or smell. Many incorrectly apply too much chemical to the water in question, which can cause slight discoloration and a bitter taste. Either chemical is shelf-stable for up to 5 years, and as little as one ounce of either compound (depending on concentration) can treat approximately 50 gallons of water. Polar Pure Iodine is a popular choice among preppers and backpackers, while Aquamira is often the brand of choice for chlorine dioxide. Both options are small and portable, housed in polymer or glass containers that measure just a few inches in height and width. The CDC puts its stamp of approval on these compounds, and many militaries use both to source potable water in the field.


Either chemical reaction can require an extensive amount of time to guarantee purification. Chlorine dioxide requires up to 4 hours to effectively kill the parasite Cryptosporidium. Some users may have mild reactions to either compound, especially if used in excess. Symptoms may include itchy or dry skin, hives or rashes, scratchy throat, headaches, and upset stomach. In extreme and rare cases, some users may experience anaphylaxis (swelling of the throat).

#4. Distillation

Distillation is considered by many to be a last-resort method of purifying drinking water: The process is slow when using natural heat or sunlight, and the yield of drinkable water is initially low. Nonetheless, distillation is another guaranteed method of purifying your water entirely: The process doesn’t allow for any form of bacterial, pathogenic, or viral contamination to remain. Distillation is a process requiring heat – much less than boiling – and patience. If using direct sunlight, extended UV exposure also aids in eliminating pathogens.

How It Works

Distillation works by allowing untreated water to heat and slowly evaporate in an enclosed space. As water vapor rises, it leaves behind contaminants and particulates, organic material, and dissolved solids. As the water vapor collects inside the enclosed space, it precipitates and recollects as small droplets of water. Over time, these distilled droplets can provide a sufficient amount of pure drinking water. Distillation even removes many soluble minerals and some harmful chemicals, like arsenic.

To effectively distill water, at least one clear container and a smaller second container are required. Glass is the best choice for the clear container to be heated. Plastic containers can contaminate the water with chemicals, especially when exposed to direct sunlight. For those who want to distill larger quantities using an open flame, a by-design distiller kit with a built-in condenser and trip tube is available.

Option #1: Fill the large glass container with untreated water. Gently place the smaller container to be filled with the distilled water in the center of the larger glass container. Ensure the rim of the smaller container is well above the untreated water line. Next, cover the opening of the larger container with clear plastic, making it tight like a drum skin. Place a small rock atop the clear plastic, creating an indentation.

As the untreated water is heated, it will vaporize. The vapor will rise, and small water droplets will collect on the inside of the plastic covering. The small rock in the center will force the water droplets to roll and cling to the center of the cover, where they’ll eventually drip into the smaller container.

Option #2: Fill the glass container with untreated water and attach a sterile hose to the opening. Ensure there are no gaps or pockets where water vapor can escape. Attach the other end of the hose to the second container to be filled. Ensure the second container is slightly higher than the untreated container, allowing water vapor to rise through the tube, where it will condense and fall back down into the treated container.


Distillation effectively purifies even the lowest-quality water with no pre-filtering or other treatments required. Distilled water is pure, tasteless, and colorless. It also guarantees elimination of infectious pathogens, viruses, and bacteria. No artificial source of heat is required: Sunlight on a warm day is often sufficient enough to distill a bottle of drinking water (with a little patience). Since merely boiling untreated water doesn’t remove large particulates, dead microorganisms and poor taste, distillation is an effective alternative if you can source sufficient heat.


Distillation often takes time and is inefficient for treating large quantities of water if one is relying on natural heat or sunlight.


  • Mechanical, portable filtration works best for the mobile prepper
  • Mechanical filtration removes most pathogens, but not all viruses
  • At-home filtration systems are available which remove all infectious sources and chemicals
  • Boiling is the most effective method for the apartment prepper who needs clean water
  • Chemical filtration is sufficient for killing all infectious sources, but requires time to work
  • Distillation is a last-resort method, but can be used in lieu of boiling to cleanse dirty water


Author Bio

Travis is a contributing guest-writer for Apartment Prepper. He also helps run, a quality source for tactical gloves, shootings glasses, ear protection, shooting bags and rifle cases, as well as certified range gear for the professional marksman.



Spread the love


  1. Thank you, Bernie. Great article! (Though it probably won’t do much for your advertising revenue from Brita LOL.)

  2. I live across the street from Lake Michigan While I have bottled water stored. I can foresee being in need to other sources like the lake. Do you ant specific suggestions for using it.

    1. Hi Carl, I am glad you have bottled water for short-term drinking needs. For lake water, first you need to filter out any solids in the water, then you need to purify it. The one I used to purify river water recently is the Survivor Filter X, which removes microbes and is battery powered. I reviewed it here: Filter water at a push of a button If you prefer other methods, here are 4: 4 easiest ways to purify drinking water Thanks for the comment.

  3. For those using iodine for water purification, consider using the new-to-market last year ‘Potable Aqua Water Purification Tablets With PA Plus” product. The “Plus” part is a second tablet you add to the water after it’s been purified that eliminates both the iodine taste and color from the water.

Leave a Reply

Your email address will not be published. Required fields are marked *