RO vs UV water purifiers- Which one is better?

FPJ Web Desk | Updated on: Sunday, August 29, 2021, 11:10 PM IST

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Due to the high levels of pollution, you need to ensure that the water that gets into your home is free from contaminants and pollutants. This is because most of the pollutants, chemicals, dirt, debris and other contaminants released into the water may be very dangerous to your health.

Water purifiers are the most effective gadgets for removing water contaminants. However, you need to understand that there are different types of water purifiers which means that they do not work the same. Reverse Osmosis [RO] and Ultraviolet [UV] water purifiers are the most popular purifiers.

What is their difference and which one is the best? Find out more details about them in this guide.

Reverse Osmosis

In reverse osmosis, water is forced through a semi-permeable material to remove impurities and contaminants. This process is the most effective when it comes to removal of viruses, bacteria and other harmful microorganisms. The RO membranes are very small which means that they are able to remove even dissolved salts.

What are the benefits of reverse osmosis purifiers?

  • If you are searching for a perfect purifier for hard water, reverse osmosis water purifiers are the best.

  • They are also effective in removal of cryptosporidium that is commonly found in rivers, lakes and public water supplies.

  • Another benefit of these purifiers is that they are able to remove toxins such as mercury, lead, chlorine, fluoride and arsenic which are dangerous to people’s health.

Ultraviolet Purifiers

Unlike the RO filters, Ultraviolet purifiers are not able to physically remove germs and other microorganisms from water. However, they are able to kill them through a powerful UV light. This light kills the microorganisms but the dead bodies remain in the water. This means that if you want to get the best results, you should try to combine UV and UF purifiers.

What are the benefits of ultraviolet purifiers?

  • In terms of price, UV purifiers are very cheap which makes them perfect for those searching for affordable options. They also cost less in maintenance.

  • They are also free from chemicals which means that the taste of water is not affected.

  • Again, they provide clean water instantly unlike the RO purifiers.

What are their differences?


The first thing you need to know about RO and UV water purifiers is that they work differently. For example, UV filters are designed to kill bacteria and viruses while the RO filters are designed to remove TDS and dead microorganisms from the water. The good thing about RO systems is that they use an activated carbon which enhances the taste of the water.

You also need to note that UV purifiers are able to kill microorganisms but they do not remove them. This means that the dead microorganisms are still present in the water you consume. Though they are harmless.

However, RO membranes are able to remove them completely although they do not have the capability of killing microorganisms like the UV lamps. To get the best results, you can look for a purifier with both UV and RO capabilities.

TDS in Input Water

The most important factor that one must keep in mind when choosing between these two types of water purifiers is the TDS in input water at your home. If the TDS in water at your home is less than 300ppm, then you need not install a RO water purifier as it would reduce the TDS in water to near 30 ppm, which according to some reports is not only un-healthy but also un-natural.

We don't know if this is correct or not, but its always a good idea to eat and drink products in their natural form. If TDS in input water is under 300ppm and we only want to remove the micro-organisms, then UV water purifiers will be able to do the job efficiently, while retaining the natural composition of water.

Water Efficiency

In terms of water wastage, UV filters don't waste water at all. On the other hand, RO water purifiers require a lot of water which is removed after filtration. Most of these purifiers waste approximately 650ml for every 1 litre of water processed, producing only 350 ml of drinking water.

However, you can direct the water into a reject tank for recycling where you can use the water for other household tasks like cleaning and washing clothes but not drinking.


When it comes to price, RO purifiers are more expensive than the UV purifiers. This means that if you are on a limited budget, you should look for a UV purifier. However, RO purifiers are the most effective since they use 5 to 6 purification stages. Due to the extra filter, it means that they are also expensive to maintain.

Storage tank

Unlike the UV purifiers, Reverse Osmosis filters come with a storage tank where water is kept after filtering. Most of them come with a 5-15 liters storage tank depending on the model. When using the UV purifier, you will need to store water manually in water containers, pots and bottles. However, some latest UV water purifiers do come with a storage tank.


When buying a water purifier, you need to be aware that some takes a lot of time to filter water. For example, RO purifiers require a lot of time to give you clean water due to the many purification stages that are involved. If you are searching for a purifier that will give you clean water faster, UV water filters are the best.


Both RO and UV purifiers require frequent maintenance to provide the best results. Reverse Osmosis purifiers are very costly to maintain as their filters plus other accessories are expensive and need to be replaced every year or so. On the other hand, UV water purifiers use only UV lamps and may be a sediment prefilter or top models may also come with a UF cartridge. Due to less number of cartridges, these purifiers are comparatively cheaper to maintain.

Final Verdict - Which one is the best?

When it comes to best purification, RO purifiers are the best in almost all aspects. As compared to the UV purifiers, they are more effective since they usually have different filtration stages. They are also easier to maintain and are the best for large families. However, UV purifiers are the best for those who are on a budget. The good thing about them is that they are able to kill all harmful microorganisms that are found in the water although they do not remove them. Plus, they retain the natural composition of water.

With our guide, we hope that now you can easily pick a water purifier for home that suits your requirements.

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Published on: Sunday, August 29, 2021, 11:10 PM IST