Different Types of Water Purification

Clean drinking water is something everyone needs. While most people can get water that is reasonably drinkable by turning on a faucet, there are times and places where that is not possible. Knowing how to purify water can be very important. 

Water that has not been filtered or otherwise processed can contain contaminants or bacteria that can be very harmful. Some of the common ones include aluminum, arsenic, barium, cadmium, chloride, chromium, copper, fluoride, lead, nitrates, nitrites, mercury, and silver, plus a host of bacteria and parasites that can cause sickness or chronic illness.

There are a variety of different ways to take random water from any source and make it something fit to be ingested. Some are simple filtering and others are more intensive.


The simplest option, boiling kills 99.9% of living organisms and sends most chemicals out in vapor. The water must boil for around 5 minutes, possibly more or less depending on altitude. Because water boils at a lower temperature at higher altitudes, it is wise to boil longer to be sure everything is properly killed or removed. This does not remove heavy metals, nitrates, solvents, or pesticides. 

Carbon Adsorption

This is a sort of filtering using activated charcoal. It removes gases, chemicals, some microorganisms, as well as chlorine. Some, but not all, remove lead, asbestos, cysts, and coliform. Because carbon attracts impurities, it makes it an excellent option for simple filtering.


Inexpensive and effective, chlorine is a quick way to kill germs, parasites, and other organisms that can be found in water. The water must stand at least thirty minutes to process; it is best when the water is warm or hot. Be careful with this one, as adding too much chlorine will make the water toxic. However, it can be obtained in tablet form, making it easy to use the proper amount. It does not remove contamination of a physical or chemical type, and it is carcinogenic and can cause heart disease, so it is best kept for emergencies only.


The oldest known method of purifying water that is known to work well for safe drinking, distilling water involves heating the water to boiling and then condensing the water. This removes up to 98% of contaminants. It works because water’s boiling point is lower than that of the minerals and contaminants, so the vapor is pure, clean water, which is then caught in a separate container.


Filtration is one of the more common methods considered when discussing water purification. This method uses a variety of different options for filtering, sometimes more than one in the same filter. Carbon, sand, or other granules are common materials through which the water is filtered. These can be affixed to a faucet, inline before a faucet, or as part of a pitcher, as well as some other possibilities.

Activated Carbon / Charcoal Filters

Charcoal, which is carbon, is a common filter ingredient. Activated charcoal, treated with oxygen, becomes very porous and can adsorb large quantities of contaminants because of their great surface area. Additionally, chemicals tend to bond to it, increasing the purity of the water. However, sodium and nitrates get through. When the carbon’s surface area is full, the filter must be replaced. 

Granular activated charcoal comes as a loose soil-like substance. This can allow faster processing of water, but it can also move in a way that allows water to slip through unaffected, so must be watched to be certain of effectiveness. 

Solid block carbon filters compress and bond the carbon to create a matrix while allows adsorption as well as filtration. These allow nutrient minerals to stay in the water while removing most heavy metals and capturing bacteria. Salts, nitrates, fluoride, and minerals such as cadmium are not effectively caught in this type of filter.

Ceramic Filter

Ceramic filters collect fibers such as asbestos and stops some bacteria, but do not collect heavy metals or other organic contaminants. When choosing a ceramic filter, look for .5 micron if possible.

Fiber Filter

These are made from fibers like cellulose, rayon, or others, made in a mesh and wrapped tightly. This makes tiny holes to let the water through while the fibers collect particles. A lower micron rating means more will be removed but also means that the filter must be changed more often.

Slow Sand Filter

This is layers of fine sand, coarse sand, and gravel, which allows the water to come in the top and exit, clean, from the bottom. No solids can get through, but bacteria and organisms may not be removed. 

Water Pitchers and Faucet Systems

Water pitchers, in which you pour untreated water and give it time to flow through the filter into the pitcher, are a popular option for clean water. The most well-known of these is Brita, which comes in a variety of sizes. The filters are easy to replace. They also offer the type that attaches directly to the faucet. Other brands include Apex, Aquagear, PUR, among others. 


This chemical purification, mostly used by campers or hikers, is a very common option. Using the proper concentration of iodine, and allowing 30 minutes to settle in warm water, bacteria and most viruses are destroyed. This does change the taste and does not kill cryptosporidium protozoa. It is important to note that there are people who are allergic to iodine. 

Ion Exchange

This method runs water through resin beads, which have replacement ions that replace some of the water ions. This de-ionizes or softens the water, depending on which ions are being exchanged. Pyrogens and bacteria are not removed with this method. 

Microporous Basic Filtration

This filters through three microporous types: screen, surface, and depth. A screen type filter is similar to a sieve – it has a uniform structure. The depth filter consists of compressed matted fibers to retain particles. Surface filters are made up of several layers of different media to filter particles; this one is excellent for removing pyrogens and microorganisms. 

NaDCC (Sodium Dichloroisocyanurate)

Tablets made from this compound dissolve in the water to be processed and creates free chlorine, which is as effective as bleach, but not as hazardous and without the taste or smell. Its effectiveness is comparable to iodine, and it has no negative effects on health. 

Reverse Osmosis

This type of purification is done by filtering the water through two different liquids which are separated by a film that only allows water and oxygen to pass through. Because it passes at a molecular level, impurities are caught in the filtering liquids and film. It takes much longer than most filtration options, despite the high pressure that pushes the water through. Without pressure, this filtration method will not work.

Ozone / O3

Ozone is an oxidizing agent that kills most organisms that live in water. It is made by putting oxygen through ultraviolet light or certain types of electricity. For it to be an effective disinfectant, it must be freshly made and added to the water through bubbles. 

Ultraviolet (UV)

Ultraviolet light is known to destroy viruses and bacteria. This is why it is often found in medical office waiting rooms. It requires a certain quantity to kill organisms; it only damages if there is not a sufficient quantity. The less clear the water is, the less effective UV light will be. Heavy metals are not affected by UV light.


Where to Buy
10 Cup Pitcher with Free Water Quality Meter
Brita Extra Large 18 Cup UltraMax Water Dispenser and Filter
Brita Tap Water Filter System, Water Faucet Filtration System with Filter Change Reminder
PUR FM-3700 Advanced Faucet Water Filter, Chrome
iSpring RCC7 High Capacity Under Sink 5-Stage Reverse Osmosis Drinking Filtration System and Ultimate Water Softener
Frizzlife Under Sink Water Filter System
Travel Berkey Gravity-Fed Water Filter with 2 Black Berkey Purification Elements
LifeStraw Flex Advanced Water Filter with Gravity Bag
Potable Aqua Water Purification Treatment
Mightie Company Worlds #1 Water Purification Tablets
LifeStraw Personal Water Filter
Prepper's Guide: How to Purify Water for Drinking and Cooking for Any Emergency


10 Cup Pitcher with Free Water Quality Meter

This pitcher with filter by ZeroWater is BPA free and certified to reduce heavy metals and filter out contaminants. Its five stage filtration uses ion exchange.

Extra Large 18 Cup UltraMax Water Dispenser and Filter

Brita’s extra large pitcher is rectangle and made to easily fit on counters and in refrigerators. It has a dispenser spout on the front for easy access. The pitcher has a sticker to allow you to easily see when it is time to replace the filter; the recommendation is 40 gallons or 2 months.

Faucet Mounted Water Filtration

Easy to connect to the kitchen faucet, this convenient filter reduces heavy metals and filters out many other contaminants. Filters are easy to replace. The unit includes a switch to go from filtered water to unfiltered water, or unfiltered spray. 

PUR Faucet Water Filter

This faucet-mounted water filter is easy to install and use. Each filter can process 100 gallons or about 2 to 3 months of average use. The filters use a combination of activated carbon and ion exchange.

Under Sink 5-Stage Reverse Osmosis Filtration System

This filtration system from iSpring fits under the sink and connects between the source and the faucet. It handles a high capacity and uses a reverse osmosis format which removes up to 99% of most contaminants.

Under Sink Direct Connect Water Filtration System

Frizzlife’s under sink system is a .5 micron filter which removes 99.99% of lead, as well as most other contaminants and heavy metals. It fits most water lines and is easy to install. High capacity filter cartridges are good for 2 years or 1600 gallons of water, though it is recommended to replace every 6 to 8 months, depending on usage.

Gravity-Fed Water Filter

Berkey offers this gravity fed water filter system which filters and removes viruses, bacteria, protozoa, minerals, heavy metals, and pharmaceuticals. Each pair of filters processes 6,000 gallons before needing to be replaced. 

Water Filter with Gravity Bag

Using fiber membrane (.2 micron) and carbon fiber, this filter is extremely effective. The hollow membrane can process 500 gallons and the carbon capsule can process 26.4 gallons before needing replacement.

Potable Aqua Tablets

50 tablets will treat about 25 quarts of water, using two tablets per quart (or liter). These germicidal tablets are good to include in preparedness kits and camping equipment.  

Aquatabs Water Purification Tablets

These effervescent tablets kill microorganisms to make water safe to drink in only 30 minutes. 

LifeStraw Personal Water Filter

Ideal for camping, hiking, or emergency preparedness, the LifeStraw unit removes bacteria, parasites, microplastics, and much more. It provides up to 1,000 gallons (4,000 liters) of safe drinking water when maintained properly. 

Prepper’s Guide: How to Purify Water for Drinking and Cooking for Any Emergency

This book can assist with learning how to purify water and help you to determine which will work best for you and your family, and possibly others around you, as well.