RO vs UV: Difference between RO and UV Water Purifiers You Should Know

Reverse Osmosis (RO) and Ultraviolet (UV) purifiers are the two most popular options in India for getting safe drinking water.

But, which one amongst the two is better?

Well, RO vs UV is what people search online the moment they decide about buying a new water purifier for their home.

Most consumers are unaware of the distinction between the two purification methods. I have seen people end up with the wrong water purifier due to this unawareness.

We won’t let you commit this mistake. This in-depth article on the difference between RO and UV water purifiers is what you need to choose the right one for your home.

However, if you don’t have enough time and is looking for a quick answer, here is what our experts say:

      • An RO water purifier is the best if your home or office has a water supply with high TDS. RO works on hard water and reduces its TDS to give you drinkable water.
      • A UV water purifier is enough if your water supply is of low TDS and is contaminated with microbes

Well, that was quick. But to know more on UV vs RO comparison, you need to understand what these two systems actually are.

Reverse Osmosis

The RO purification process involves forcing water through a semi-permeable membrane.

      • It works using water pressure, which eliminates impurities and contaminants.
      • We highly recommend the method for tap water with high contents of total dissolved solids (TDS).
      • By removing hardness, it gives the water a sweeter taste.

If you are staying in an area with high TDS water supply, you can buy the best RO water purifier to safeguard your family from water-borne diseases

The reverse osmosis system, however, is not as effective in killing microorganisms. But, the best thing is that most of the RO water purifiers are coming with additional technologies like UV, UF etc.

Ultraviolet Purification

Yes, these are the ultraviolet rays you were always told to stay away from.

The ultraviolet rays are of three types. The UVA emissions are sun tanning rays, while the UVB ones are sun burning rays. However, the third kind is the UVC rays which have germicidal qualities.

UVC is effective in killing illness-causing bacteria and viruses.

UV water purifiers have the water passing through a chamber containing a UV lamp. The intense light then does its job in deactivating harmful contaminants.

However, keep in mind; the UV rays are not effective in lowering the TDS value.

At a lower TDS level, you really don’t need an RO purifier. A UV purifier is more than what you require to kill the viruses and bacterias contaminating your water supply. If you fall into this category, don’t forget to check out some of the best UV water purifiers. NB: They are very affordable!

RO vs UV Water Purifiers: A Detailed Comparison

RO vs UV water purifier comparisons

Before committing to a particular product you need to dig deep and understand which works best for you.

We have compared RO and UV water purifiers’ performance in 9 different areas below. I am sure this will give you the right answer.

Let’s go!

When to Use

Many of the underground water sources in India are primarily polluted by industrial waste. They also contain high TDS, making the water unfit for consumption.

      • As mentioned above, the reverse osmosis system works effectively in removing high TDS.
      • In doing so, it reduces the hardness of the water, making it usable for daily chores.
      • On the other hand, since UV filters are unable to change the TDS, they are not recommended for well water.

Nonetheless, UV purifiers can work well with lakes, rivers, and even municipal water supplies. Due to already low TDS levels, all the purifier needs is to eradicate microorganisms, making the water healthier.

In the case of muddy water, both UV and RO purifiers will require a pre-filter. The sediment filter will separate the dirt particles from the clear water.

TDS More than 300 PPM Less than 300 PPM
Microbes RO alone can’t remove microbes. But a combination of RO+UV is very effective UV purifiers remove microbes independently


In terms of price, UV purifiers are mostly inexpensive. The pocket-friendly method is for those on a tight budget and in need of a purifier that only kills microorganisms.

However, due to a multi-scale performance, reverse osmosis systems are two times costlier than UV filters. Moreover, the RO systems typically consist of five to six stages of purification. The added filters mean more maintenance costs, as well.

But you need to remember that RO filters are still worth the cost due to their excellent performance and effectiveness.



Maintenance is a significant part of the process when we talk about purifying systems.

      • Several electrical components require regular servicing to ensure better performance.
      • Moreover, due to the polluted environment in India, dust seeps into the filters hindering their performance.
      • Additionally, most UV filters require lamp replacements which can be costly. However, this maintenance is not regular, making it relatively cheaper.
      • Reverse Osmosis, in contrast, needs cartridge and membrane changes which can be heavy on the pocket.

Although both the purifiers require regular maintenance, RO purifiers’ maintenance cost is on the higher side.

Energy Consumption

Both UV and RO purifiers work on electricity. Most RO purifiers come with an energy-saving feature which shuts off the system when not in use.

It is also pivotal to note that RO purifiers require energy to boost water pressure. This boost is essential to push water through the membrane to filter out pollutants. UV, on the contrary, works with regular tap water pressure, reducing the need for electricity.


The two systems also vary based on performance. In short, they work differently for different reasons. The UV filters target bacteria and viruses, killing them in the process.

However, RO filters work on several issues at the same time.

Not only do they reduce the TDS, but they also filter out dead microorganism bodies. The activated carbon filters in RO systems enhance the taste, making it sweeter for the consumer.

A critical difference between UV and RO is that the UV lamp kills microorganisms. However, these dead bodies still float in the water you consume. The RO membrane, however, filters out these floating bodies.

Do not forget, RO cannot kill these microorganisms like the UV filters.

Time to Purify

Time matters, even for water purifiers. You can’t wait for hours to get the water purified. So, this is something you should look into if your home needs a lot of water every day.

Due to the difference in stages of purification, UV filters deliver water in much less time.

Reverse Osmosis, on the other hand, passes water through several stages, each taking it’s time to cleanse the water.

Water Wastage

The UV filter does not require additional water, which means there is zero water wastage.

However, reverse osmosis uses additional water which is then drained out. Due to a high level of TDS in this water, it becomes undrinkable.

Most purifiers waste about 650ml of water for every 1 litre of clean water. This amount can be filled into a reject tank and recycled for household chores like washing and cleaning. You can read about Reverse Osmosis waste water recycling here.


Typically, UV purifiers do not come with a storage tank. That means you need to fill pots or bottles of water manually each time.

RO systems typically consist of a storage tank with a capacity of five to fifteen litres depending on the model. It offers enough space to store purified water for the day.

With this, you will not have to use the system frequently, saving electricity in the process.

UV vs RO Differences in a Glance

RO Water Purifier UV Water Purifier
It is best suited for Underground water sources. It is best suited for Municipal water supplies.
There is a lot of wastewater involves with RO systems UV produces zero wastewater.
The purifier removes TDS and dissolved solids. It does not remove TDS.
RO cannot kill impurities but removes all dead bodies. The UV light kills microorganisms.
It enhances the taste and odour of ordinary tap water. UV cannot alter taste and aesthetics.
RO takes time to purify water. It takes far less time than RO in producing water.
Typically most RO systems contain a storage tank It does not contain any storage capacity.
It costs double as much as UV The system is cheaper than RO
High maintenance cost Low maintenance cost

RO or UV Water Purifier, Which is Better for You?

While most reputed authorities deem municipal water suitable for consumption, the ground reality is far from it. This creates a need for water purification systems that eliminate impurities from tap water, making it drinkable.

Without any doubt, RO and UV purifiers are well-known globally for their performance. The contaminated water sources in India demand purifying systems that offer healthier output. Both RO and UV, for this matter, are efficient systems.

The only way to decide what’s best for you is to get a Lab test of your water. It will clarify the kind of impurities present in the water and the method required for it.

Reverse Osmosis may be an expensive system, but it works perfectly for Indian water conditions. However, the most recommended step would be to get a combination model of RO+UV+UF for the best results.

I hope our RO vs UV comparisons have helped you to select the right water purifier for your requirement. If you want to know anything more, please free to ask in the comments.

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