Types of Water Purifiers – UV, UF, RO Water Purifiers

Our drinking water sources are contaminated with various kinds of impurities like TDS and industrial wastes. This makes it unfit for drinking. Hence, this situation calls for taking drastic measures for purification of drinking water. One such method is the use of different types of water purifiers.

There are various kinds of water purifiers available in the market. Ranging from the simple candle filters to the most advanced multi-stage water purifiers, you have a wide choice. Each of these machines has their individual advantages and disadvantages. Let us look at them in this article.

1.  Basic Candle Filters

This is the simplest form of filter in use in many households. This equipment consists of either one or two candle/sediment filters that are capable of trapping visible impurities. However, it cannot trap impurities that are smaller than the pores of the candles. It cannot prevent microbes thereby necessitating boiling of water before consumption. The candles need frequent replacements for efficient operation.


  • Simple to use.
  • Inexpensive and easily available.


  • Cannot eliminate microbes.
  • Candles require changing at frequent intervals.

2.  Gravity-Based Water Purifiers

These filters work on the simple principle of water moving from a higher chamber to a lower chamber because of difference in pressure. You have some common filters like germ filters and micro-fiber filters to trap dust particles and dissolved salts.


  • Does not require electricity.
  • Inexpensive.
  • Good storage capacity.
  • Portable and easy to use.


  • Does not filter high concentration of TDS.
  • Cannot eliminate micro-organisms and heavy metals.

3.  Reverse Osmosis Water Purifiers

The gravity filters cannot take care of the heavy metals like arsenic and mercury. You need special technology like ‘reverse osmosis’ to remove them. This system envisages water to pass through a semi-permeable membrane which ultimately removes fluorides, nitrates, and other dissolved salts and impurities. This filter has utility in homes and companies.


  • Capable of treating water with high TDS.
  • Excellent for purifying hard water.
  • Good storage capacity.
  • Removes heavy metal impurities like arsenic and lead.


  • This process wastes a lot of water.
  • RO cannot kill germs and bacteria.
  • High maintenance cost.

4.  Ultraviolet Water Purifiers

These water purifiers use ultraviolet radiation to get rid of germs and viruses. Hence, they are useful for making water free from harmful microorganisms that causes diseases like cholera, typhoid, and dysentery. However, ultraviolet purification process does not remove dissolved salts from water.


  • Eliminates bacteria and viruses that cause water-borne diseases.
  • No wastage of water during ultraviolet purification.
  • No use of chemicals thereby maintaining original taste of water.
  • Less maintenance cost.


  • Does not remove dissolved salts and impurities like nitrates, fluorides, lead, and arsenic.

5.  Ultrafiltration Water Purifiers

This method envisages the use of ultra-filtration membrane for purifying water. In comparison to the RO membrane filters, these UF membrane purifiers have larger pores. This can take care of germs and bacteria, but allows the dissolved salts to pass through.


  • No need for electricity to operate.
  • Removes all kinds of germs and bacteria from water.
  • Manual cleaning facility ensures easy maintenance.
  • Long-lasting filters.


  • Incapable of removing heavy metals like arsenic, lead and salts like nitrates and fluorides.
  • Only capable of treating water with low TDS levels.

6.  Multi-Stage Water Purifiers

You have just seen five different types of water purifiers described above. Each of the purifiers has some advantages and disadvantages. They are beneficial in some way whereas proving ineffective in some other vital aspects. Hence, the need of the hour is a water purifier that can use the combined strength of all the above-mentioned water purifiers. Thus, it will negate the disadvantages at the same time.

The modern-day multi-stage water purifier is a combination of all the systems listed above.  Let us look at the salient features of the various combinations you get in the market.

  • RO+UV: This combination gives you high-quality pure water as it combines the RO and UV technologies. This ensures that it takes care of germs, bacteria, viruses, heavy metals, and other dissolved salts.
  • RO+UV+UF: This kind of water purifier moves one step forward and provides pure water of the best quality. In addition to the RO and UV technologies, you have the advantage of the UF technology. You can use these filters in areas where there is a high level of TDS.
  • Pre and Post Activated Carbon filters: These filters can absorb toxic chemicals like arsenic and various kinds of pesticides. They are very useful to improve the odor of the water. They block the major impurities from sticking to the RO membrane thereby increasing the lifespan of the RO membrane.

You have the modern water filters having a combination of the sediment filter, pre-activated carbon filters, RO membrane, UV systems, UF equipment and finally the post activated carbon membrane. This 6-stage water purification system ensures that you get the purest quality of drinking water. Let us look at the advantages and disadvantages of these multi-stage water purifiers.


  • Useful to treat hard water.
  • Enhances taste of water by supplementing it with certain minerals.
  • Removes all kinds of impurities like dissolved salts, toxic pesticides, and heavy metals.
  • Eliminates germs, bacteria, and viruses of all kinds from water thereby making it safe.


  • These water purifiers require continuous supply of electricity.
  • High maintenance costs as it involves a combination of various kinds of water purifying systems.

As mentioned above, you can use any type of water purifier to drink safe water. The traditional purifying method would become obsolete in the near future. With changing time, modern technologies are being adopted in order to ensure that you drink the best quality water.

Because of the high level of pollution in drinking water sources, in the future almost all of us would have to use water purifiers and it will become more of a necessity for households to protect their dear ones.