RO vs UV Purifier: Which One is Right for You? (By Experts)

Washing dishes after your dinner, giving bath to your canine in the tub, offering cold water to the guest during harsh summers — we use water in almost everything.

And having fresh, clean water is what makes all those moments a bit more pleasant— figuratively speaking.

However, as you start exploring the water’s contaminants, you might get tangled with the water purifiers and the industry jargon as everyone claims their water purifier is best in the biz.

Speaking of water purifiers, the most common ones people search for are RO and UV Water Purifier.

…But which ones better? At least for you?

Let’s take a look at that.

What is TDS?

Now before we jump directly into water purifiers, you will find TDS appearing a lot whenever someone mentions RO or UV. So we took the liberty to explain that term to you.

Basically, TDS stands for Total Dissolved Solids, which represents the concentration of substances dissolved in water. TDS forms small amounts of organic matter and inorganic salts.

These inorganic salts are very common in water that includes magnesium, calcium, sodium, and potassium. These all are positively charged ions, also known as cations. It also consists of negatively charged ions, which are known as anions.

Anions such as carbonates, sulfates, chlorides, bicarbonates, and nitrates are also present in water. These minerals are present in water naturally as well as due to human activities.

What is RO Water Purifier?

RO Water Purifier

RO, otherwise known as the Reverse Osmosis water purification system, is a water purifier that helps to remove unwanted and harmful dissolved substances in water such as salts, ions, and TDS.

RO water purifier works just the way they sound, opposite of osmosis technology. With that being said, reverse osmosis is not that effective in killing microorganisms; they are excellent for cleaning high TDS waters.

So if you have a high TDS water source, you can look for the RO water purification system.

How Does RO Water Purifier Works?

Generally, reverse osmosis purifiers have a 0.0001-micron pore size. Therefore, once the water passes through these purifiers, it is mostly purer water.

Besides removing all the viruses, reverse osmosis also eliminates many minerals. Reverse osmosis is also responsible for eliminating monovalent ions, meaning that it desalinates the water (Desalination means — the removal of salt from the water).

To get a hold of the reverse osmosis process, first, you will need to get an idea about the osmosis process. Osmosis is the spontaneous movement of molecules from a low concentration region to a high concentration region through a semi-permeable membrane.

The molecules will keep moving till the concentration is the same on both sides. The partially permeable membrane or semi-permeable membrane facilitates the water to pass through but doesn’t allow larger molecules dissolved in water to pass through. Check the diagram!


Since reverse osmosis is the opposite of osmosis, it works just the same, but in this case, the flow of water is reversed with the help of pressure. Due to this pressure, the water is constrained to go from the high concentration region to the low concentration region.

Thanks to the pressure, we get fresh, clean water from one side, leaving behind all the contaminants on the other. Check the diagram!


The reverse osmosis water purifiers also clean dirty water with the help of prefiltration. The later stages eliminate the bacteria and infection. However, it requires additional electricity to boost the pressure coming from the tap.

Since reverse osmosis alone cannot remove the microbe, most people prefer the combination of RO + UV Water Purifier. It is an effective and excellent way to get the best of both worlds.

Pros and Cons of RO Water Purification System

Here are some of the merits and demerits of using a reverse osmosis water purifier to make it simple for you.

Excellent for High TDS waterIt wastes a lot of water
Effective in filtering — thanks to 0.0001-micron probe size.Consumes more electricity
Filters both visible and suspended impurities as well as practical for muddy watersIt also removes all the minerals from the water like calcium, sodium, magnesium, and potassium.

What is UV Water Purifier?

UV Water Purifier

UV water purifiers or also known as Ultraviolet water purifiers are the most cost-effective ones out there in the market. Unlike RO, UV has the ability to kill bacterias, viruses, and germs without altering the taste.

Since ultraviolet water purifiers can work with regular tap water pressure, they don’t require additional power to boost the water. They kill all the bacterias and germs so that the water is clean, safe, drinkable, and disinfected.

How Does UV Water Purifier Works?

The UV water purifier exposes the living organism such as cysts, bacterias, and viruses to a germ-killing ultraviolet wave. A sleeve emits this germicidal wavelength for killing the bacterias. With the help of adequate energy, the UV radiation at 254-nm travels and destroys the viruses as well as prevents their reproduction cycle.

When it comes to UV purifiers, UV dosage is the first thing you need to understand: the higher, the better for decontamination of your water. When you keep it at the recommended threshold, it is sufficient to eliminate the microorganisms.

However, having said that, UV purifiers are not effective in lowering the water’s TDS value. So if you have a lower TDS level and more bacterias to deal with, consider picking up a UV water purifier.

Pros and Cons of UV Water Purifier

Listed below are some pros and cons of opting for a UV purifier.

Effective in decontamination of the water by killing visible and invisible bacteriasThe killed bacterias stay in the water
No wastage of waterCannot disinfect muddy water
Can work with normal tap pressureTDS valve does not change if the water is purified from this purifier.

RO Vs UV Water Purifier

RO and UV water purifiers are significant, depending on the usage. Given that you have all the necessary information let’s compare it with the table below.

It requires electricity for purification.It requires electricity for purification.
Effectively filters out the germs and bacteria from the water.Effectively kills all the bacteria and germs from the water, but their corpses remain still in the water.
This water purifier requires more water pressure, so an extra pump is used in most RO water purifiers.This water purifier works with regular tap water pressure and thus doesn’t require any boost.
Easily removes dissolved salts and organic matter.It cannot eliminate dissolved salts and other harmful metals.
RO water purification systems filter out visible impurities suspended in the water, such as rust, sand, mud, and so forth.UV water purification cannot filter that and thus needs clear water.
These water purifiers come with a 0.0001-micron membrane size.These water purifiers have no membrane.
RO water purifiers can reduce up to 90% TDS.UV water purifiers cannot deal with high TDS levels.
These water purifiers waste a ton of water.These water purifiers have zero wastage of water.
It cannot remove microbes from water independently.It can easily remove microbes from the water independently.
RO water purifiers are great for Underground water sources.You can opt for a UV water purifier for municipal water supplies.
It consumes time to purify.Compared to RO, it takes less time.
Generally, most RO water purifiers contain a sort of storage tank.On the other hand, UV water purifiers do not contain any type of storage tank or capacity.
RO water purification systems demand high maintenance costs.UV water purification systems don’t require much maintenance costs.
These water purifiers tend to be on the expensive side.These water purifiers are affordable — at least cheaper than RO.

Some Factors to Consider

When settling on either one of those, you will need to look at these factors and then decide. Here are some key factors that will help you with your selection process.



Cost is something that alters the decision of many, and water purifiers are not an exception. In terms of price, reverse osmosis water purifiers are on the costlier side. Since they provide multiscale performance, have almost six stages of purifications, and deliver excellent effectiveness.

Howbeit, UV water purifiers are pocket-friendly and a thrifty alternative for those tied with a budget.

Verdict:- UV water purification system is an excellent choice for low-budget people. Be that as it may, the RO Water purification system wins the show here, albeit at a high cost. They are practical and deliver outstanding performance.



In the case of RO water purifiers, the quality is the deciding factor. A low-quality RO can require a lot of regular replacements of the filters. At the same time, a good quality RO water purifier will give not only 100% clean water but also low maintenance hassles, but you will still need to replace some if not all filters after a year or two.

As far as UV water purifiers are concerned, they require little to no maintenance since they run on a UV lamp. Though there is no fixed way to figure out the UV lamp’s longevity, the experts recommend changing it after a year and a half.

Verdict:- RO water purifiers will require more maintenance even if they are of good quality. UV lamps will not trouble you with frequent maintenance hassles.

Water Source

Water Source

Since RO water purifiers come with a prefilter, they can easily clean muddy water or murky water whilst removing the bacterias and impurities during purification. Therefore, RO can handle highly impure water without a hitch.

On the other hand, UV water purifiers do not contain any sort of pre-filters to deal with the physical impurities.

Verdict:- Even though UV water purifiers are a great way to kill viruses, they cannot handle dissolved substances in the water; for that, you will require an RO.



UV purifiers kill the microorganisms with the help of ultraviolet waves. RO purifiers are a bit multifarious; they filter and reduce TDS while also filtering out the microorganisms’ dead bodies. Not only that, the carbon filters in the RO enhance the taste of the water, thus making it sweeter.

Verdict:- The key difference is that UV kills the bacterias, but their bodies remain in the water you consume; RO filters out those bodies but cannot kill the microorganism.

Energy Consumption

Nowadays, most water purifiers come with energy-efficient features that shut down the purifier when not in use.

In terms of consumption, both water purifiers consume electricity, but RO consumes a bit more than UV because it needs the boost of water pressure to filter out the contaminants. UV works wonders with the standard water pressure coming from your tap.

Verdict:- Energy consumption is a little higher in RO water purifiers compared to the UV purifier.

Water Wastage

Water Wastage

Well, there is no wastage of water when opting for UV purifiers.

However, RO purifiers are notorious for a ton of water wastage as they have extra filtration, and they need more water to filter clean water. On average, RO purifiers need 3 liters of water to offer 1 liter of clean water.

Verdict:- RO purifiers waste a lot of water than UV; though you cannot drink the wasted water, you can still reuse RO wastewater.

So Which One is Better For You? — RO or UV?

Well, it depends on the area you are living in and the water you are consuming. Is your water supply from the ground like borewells or tankers or even both? Or from the municipality?

In the case that you have your water source coming from the municipality, then there are no TDS to deal with, and you only need to kill bacterias; this seems perfect for UV purifiers.

On the flip side, if your water is from a ground source, then there are chances that the water has high TDS levels; in this case, you can go for RO purifiers.

As a general rule of thumb, you should check your groundwater with the TDS meter’s help. According to WHO,

TDS Level (MG per Liter)Rating
Less than 300Excellent
300 to 600Good
600 to 900Fair
900 to 1200Poor
Above 1200Unacceptable


If your TDS levels are lower than 500, you should opt for UV purifiers; however, if it exceeds 500, then you should go with RO purifiers.

Our recommendation would be to get the best of both worlds by looking for some combinations like UV + RO or RO + UV + UF for the best possible results.

Our Thoughts

When we talk about Indian water conditions, a water purifier is a must; both RO and UV are excellent for purifying your water. However, relying on a single water purifier is not a smart idea here.

Every purifier has its own pros and cons; what we need is multitudinous. That’s the reason we would recommend going for combinations to get the advantages of both the technologies.

Hope you got what you were looking for, and if you have any doubts or questions — you know what to do.

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