Confused About The Various Methods of Water Purification?


There are various methods of water purification and filtration, some more effective at removing certain types of contaminants than others.

Whilst there are contaminants in every water supply, the methods of water purification and filtration you’ll use will depend on 3 things: (1) the state of your local water supply; (2) the cost and performance of the filtration unit and (3) their health-benefits.

Also note that there is a difference between purification and filtration.

Water purification involves the removal of microbiological contaminants from your water supply, usually (but not always) by adding a disinfectant, like chlorine treatment. Read more about the types of contaminants found in your water supply.

Some home water filtration systems can remove chemical contaminants for example, but fail to effectively remove microbiological ones (bacteria) from your water supply. Therefore, these are not “purifiers” in the true sense of the word.

Some salespersons will interchange the word “purifier” and “filter” with no regard for their true meanings. Read more about water purifiers.

To help you gain a better understanding of the major methods of water purification and filtration, the following summary has been created:

water ionizer



a) Many health experts report that ionized water reduces the likelihood of many diseases and also make you look younger.


a) Debatable health claims.

b) Very limited water filtration ability.

Read more about water ionizers

Iron Filters


a) Excellent for removing iron, manganese and hydrogen sulfide from your water supply.

b) They are small, simple to install and have relatively long life.


a) Minimal or no removal of arsenic, bacteria, chlorine, fluoride and VOCs.


Iron water filters are great if your only concern is the removal of iron from your water supply. But if you are looking for a more comprehensive removal of contaminants, use a whole house water conditioner.

reverse osmosis water filter system

Reverse Osmosis (ro)


a) Good at removing, foul tastes, smells, colors.

b) Very effective at removing dissolved minerals and heavy metals like aluminum, arsenic, chloride, chromium, copper, fluoride, magnesium, iron, lead, manganese, mercury, nitrate, silver, and sulfate.


(a) Wastes water and very slow. For every 5 gallons of filtered water, a reverse osmosis water filter waste around d 10 – 20 gallons of water.

(b) Strips water of vital minerals that the body needs

(c) Ineffective at removing almost all synthetic chemicals (like herbicides and pesticides) since their molecules are smaller than water (unless used with an activated carbon filter.

(d) Filters limited amounts of microbiological contaminants and membranes subject to serious bacterial attack. Hence some systems are sold with an ultra violent (UV) disinfectant.

(d) Cellulosic membranes used in ro systems may contain 1,4, Dioxane, a substance known to cause cancer. Manufacturers of ro systems that use these membranes are required to place warning labels about this.


If you’re going to buy this system, the more filtration stages it has, the better. Also, it is best to get an activated carbon reverse osmosis filtration system. Such a system will eliminate a very wide range of drinking water contaminants.



a) Of all the methods of water purification and filtration, distillation is considered in some quarters to be the best.

b) It removes the widest variety of contaminants such as salts, chemicals, bacteria and other micro-organisms from your water supply.

c) Water distillers provide almost pure water, is compact and can be moved easily to another location. Cons:

a) Produces flat tasting water that is stripped of the trace minerals that your body needs.

b) Some doctors contend that this can lead to multiple-mineral deficiencies within the body. However some experts contend that most of the bodies mineral needs are met through eating food, not drinking water. Therefore the effect of de-mineralized water on the body is still being hotly debated.

c) Water distillers have low filtration capacity and uses a high amount of electricity. When the cost of a water distiller itself is added to the cost of electricity and water, the cost of producing one gallon of distilled water could run between $0.15-$0.35/gallon.

d) Especially in cheap units, water distillers have limited effectiveness in removing synthetic chemicals. Almost all synthetic chemicals boil at temperatures lower than what water does. Therefore, some of these chemicals are carried over into the distilled water that is provided. Read more on water distillers.


If drinking water stripped of it’s natural mineral content doesn’t bother you, getting a water distiller is a good option. To get the water even more pure, use a distiller in conjunction with a carbon filter which would help remove the synthetic chemicals.

ultraviolet water filter

Ultraviolet Water Purifiers:


Considered one of the most effective methods of water purification. That is, they’re excellent at removing bacteria and parasites like cryptosporidium, giardia, molds, algae and yeast.

They can purify around 10 gallons/minute yet energy efficient and is easy and cost effective to install and maintain. Furthermore, it and adds no chemicals to your water hence your water taste remains unchanged. Read more about ultraviolet water purification.


An ultraviolet water purifier has limited effectiveness in filtering water, that is, removing chemical contaminants like chlorine, heavy metals and volatile organic compounds (VOCs). UV light generally has no impact on chlorine, VOCs, heavy metals, and other chemical contaminants.


An ultraviolet drinking water filter is usually installed as part of an under sink unit. Since it is not very effective in removing chemical contaminants, it is best to use it in conjunction with other systems, like the activated carbon block or reverse osmosis filters.

Water Softeners/Water Conditioners:

More information on the pros and cons of water softeners

Methods of Water Purification – The Conclusion:

None of the methods of water purification and filtration can remove all contaminants from drinking water.

To have a clearer understanding as to which household water filter to buy, you could get a copy of your local water report. This will tell you what contaminants your water supply have. Then you can get the household water filter that best removes those contaminants.

Overall, a water distillation system removes the widest range of contaminants. However as stated before, there is a potential health risk in using this method.

Furthermore, most household distillers are point of use and used predominantly in the kitchen. Therefore, they don’t provide filtered water to the entire house.

Conversely, a whole house water filtration system is a good option for providing safe, clean water throughout your home – your shower, dishwasher, washing machine, faucets etc.

Some people use a water distiller or point of use reverse osmosis filter to provide drinking water and a whole house filter for other purposes.

Another consideration as to which of the methods of water purification to choose is affordability. House water filters are offered in various price ranges, so what you can afford may ultimately decide which one you buy.

Even if you can only afford to get a cheap water filter, it is certainly better than having no filter at all.

Return from Methods of Water Purification & Go To Best Water Filter Guide

drinking water filtration


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