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Pros and Cons of Different Methods of Water Filtration

Water filtration has many different benefits to offer. Filtering can remove any harmful pollutants that may be present and improve the taste of your drinking water. It can also reduce reliance on single-use plastic water bottles, helping protect the environment.

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As there is such a variety of uses for water filtration, there’s a wide range of different methods available. Whether you want to reclaim wastewater in an effort toward sustainability or merely make your water taste better, you’ll want to choose your filter carefully. Not all filtration systems give the same results.

There are a lot of things to consider when looking for a water filtration system. Filtration methods vary in strengths, prices, convenience, and usage. Listed below are the pros and cons of the different techniques you may come across.

Activated Carbon

Activated carbon filters are some of the most common water filters you’ll find. Also called “charcoal filters,” these systems use a process called adsorption to extract impurities from water. Contaminants are naturally attracted to carbon, so they adhere to it as water passes through the filter.

Charcoal filtration is a popular choice for smaller home systems such as water pitchers and faucet filters. Activated carbon filters are typically inexpensive and easy to find, but you’ll have to replace them periodically. While carbon does remove chlorine, mercury, and bad tastes, it does not remove fluoride or dissolved solids.


  • Improves the taste of drinking water
  • Does not require installation
  • Removes harmful impurities
  • Affordable
  • Widely available


  • Not all carbon filters remove lead or other heavy metals
  • Need to be replaced periodically
  • Does not remove all contaminants
  • Slow filtration

Activated Alumina

Activated alumina filters are far less common than their activated carbon counterparts, but they use a similar process. As water passes through, some contaminants cling to the alumina due to a natural chemical attraction. Where alumina and carbon filters differ is the specific pollutants they attract: while carbon attracts things like mercury and chlorine, alumina attracts material like fluoride and arsenic.

Some people believe that activated alumina adds aluminum to water, but this is a misconception. Alumina is safe and does not add aluminum, but this does not mean it doesn’t have its share of drawbacks. The process is not always effective at different pH levels and disposal of alumina filters can be inconvenient.


  • Removes fluoride
  • Effective at removing dissolved solids and sulfates
  • Relatively inexpensive


  • Limited lifespan
  • Requires careful disposal
  • Effectiveness can vary depending on pH levels

Ceramic Filters

Water filtration doesn’t have to be high-tech. Ceramic filters take advantage of earthenware’s porous surfaces to filter water simply and cost-effectively. Millions of microscopic pores in the ceramics trap impurities but still allow water to flow through.

Manufacturers will often coat the ceramic components in colloidal silver to increase their effectiveness further. Due to their simplicity and the availability of their elements, these filters are cheap and accessible. But while they are proven effective at removing bacteria and protozoa, they are less effective against smaller pathogens like viruses. They also run a higher risk of recontamination.


  • Extremely affordable
  • Accessible even to remote or disadvantaged communities
  • Effective in removing bacteria and protozoa
  • Long lifespan if cared for properly


  • Less effective at eliminating viruses
  • Need to be cleaned regularly
  • Ceramic parts can break easily


You’ll most often see the term “distillation” in reference to alcoholic beverages, but it’s also a method of purifying water. This process involves boiling water into steam in one chamber and then condensing it back into a liquid in a separate compartment. The heat kills microbes like bacteria, and the vaporizing process leaves heavy metals and other harmful materials behind.

This method often takes the form of either solar distillation or multi-stage flash distillation, both of which are relatively large and complex systems. You can buy distilled water in bottles, but this increases single-use plastic consumption and may also be costly in the long run. Distillation also doesn’t remove contaminants that have a lower boiling point than water, and it can remove healthy minerals.


  • Removes heavy metals
  • Kills bacteria and other pathogens
  • Removes fluoride


  • Expensive
  • Doesn’t remove all contaminants
  • Takes up a lot of space
  • Removes minerals


Microfiltration doesn’t rely on chemical processes to purify water like distillation and activated alumina. Instead, it moves water through a fibrous membrane, removing contaminants physically. It works much like a mesh strainer, but the holes are microscopic, so they let less through. Microfiltration membranes usually consist of durable materials so that they can resist harsh elements for a long time.

These membranes are more suited to industrial, large-scale use, so their prices run comparatively high. But microfiltration systems are relatively energy-efficient, which can help offset initial costs. While they are effective at filtering out solids and bacteria, they do not remove all dissolved contaminants.


  • Removes heavy metals and other solids
  • Effectively removes bacteria
  • Energy-efficient
  • Durable


  • Does not remove all dissolved contaminants
  • Not ideal for personal use

Reverse Osmosis

Reverse osmosis is similar to microfiltration in that it uses physical filters. This method uses a series of different filters to remove impurities, but it doesn’t merely push water through them and into a reservoir. As the name implies, it uses pressure to reverse the natural process of osmosis, forcing water from a higher concentrated solution into a lower concentrated one.

Reverse osmosis requires you to use clean water in the process as the lower concentrated solution, so it ends up wasting some water. It can also be an expensive option, with high upfront costs and the need for regular maintenance. But for this cost, reverse osmosis does remove almost all contaminants, and the systems are usually convenient.


  • Removes most contaminants
  • Convenient to use
  • Improves water’s taste


  • Expensive
  • Requires frequent maintenance
  • Leads to wasted water
  • Removes minerals

Ultraviolet Filtration

Ultraviolet water treatment is not very common, but it is an option. This process uses UV radiation to kill harmful microorganisms that may be in the water. It’s an astoundingly effective method in this regard, destroying almost all bacteria and other microbes.

UV filtration systems may be expensive to buy and install, but they require little maintenance and don’t use a lot of energy. While they are safe and environmentally friendly, they do not remove contaminants like heavy metals or other suspended solids. Ultraviolet light cannot thoroughly purify water on its own, so you’d have to use it in tandem with another method.


  • Extremely effective at removing microbes
  • Energy-efficient
  • Environmentally friendly


  • Cannot purify drinking water on its own
  • Requires electricity to operate
  • High initial cost

Infrared Filtration

Infrared filtration is a relatively new purification method. These filters expose water to infrared light as it passes through, removing impurities like bacteria. Like UV filters, infrared filtration systems do not remove all contaminants, so they can’t produce pure drinking water on their own.

Infrared filters differ from UV filters in that they can soften water. Hard water is water that is high in calcium and magnesium, which can decrease the effectiveness of soaps or clog pipes over time. Infrared light removes these minerals, softening the water.


  • Effective at removing microbes
  • Softens water
  • Easy to install


  • Does not entirely purify water by itself
  • Costs can be high

Water Ionization

Water ionization is a complex process that purifies water by attempting to raise its pH level. These systems use a process called electrolysis to separate water into acidic and alkaline streams. The system then treats the alkaline stream, which comes out of the faucet.

There are many proponents of alkaline water, but there is no medical evidence to suggest that it has many benefits over other forms of clean water. While alkaline water itself may not have any advantages outside of tasting better, many water ionizers contain useful filters that remove harmful contaminants. Ionizers are often expensive, which may make them less desirable than other, more affordable methods of purification.


  • Many ionizers have effective internal filters
  • Can improve the taste of drinking water


  • High initial cost
  • Often claim to offer benefits that are not medically proven

Choosing the Right Filtration Method

There’s a wide variety of filtration methods on the market, so it may be challenging to choose the right one for your own needs or desires. Water purification systems provide many advantages to your health and protect the environment, so you should take the decision seriously. No one kind of filter is superior to all the others, as the best choice depends on your specific situation.If money is an issue, you shouldn’t feel tempted to pay more than you are comfortable with for a high-tech filter. Ceramic and activated carbon filters can provide clean water for a small cost. If you have no objection to spending more money, you may consider paying for a more comprehensive system like using infrared treatment along with another method.

You should also consider your intended purpose for the filter. If you’re only interested in better-tasting water, a cheaper, smaller charcoal filter will be sufficient. If you’re looking for large-scale, thorough purification, look at more complicated systems like microfiltration or reverse osmosis.

No matter your end goal or budget, there is a filtration system available that will suit your needs.


Emily Folk is a freelance writer and blogger on conservation and sustainability. To see her latest posts, check out her blog, Conservation Folks, or follow her on Twitter, @emilysfolk.


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