RO vs UV vs UF – Water Purifiers

Last Updated on 15 February, 2024 by Sourav Roy

RO vs UV vs UF Water Purifier – You’ve reached this article. That means you are trying to understand the differences between these three types of water purifiers, their functions, advantages and disadvantages. And you are trying to figure out which one is right for you.

Don’t worry. You’ve come to the right place. In this article, we will learn about RO (Reverse Osmosis), UV (Ultraviolet) and UF (Ultra-Filtration) water purification technology. We will talk about the advantages and disadvantages of each of these technologies. And we will make a comparison between them so that you can choose the right water purifier for you.

RO vs UV vs UF - Water Purifiers

You may know that 71% of the earth’s surface is surrounded by water. And 96.5% of the world’s water is found in the oceans which is unfit for drinking. Of the remaining 3.5%, more than 2.5% of water exists as ice, clouds and steam. Less than 1% of water is available for use by humans, animals and plants as waterfalls, lakes and groundwater.

We human beings are polluting this minimum amount of usable water by our irresponsible and reckless actions. Groundwater pollution is one of the major problems in India at the moment. Now the natural water we get in wells, rivers and reservoirs are no longer pure. The water pollution has increased so much that even rainwater is being polluted, which is often known as acid rain.

In almost every city and suburban area in India, municipal corporations try to provide clean water to the residents through the supply network. But unfortunately, due to leakage in the pipeline and lack of proper maintenance most of the time, they fail to supply 100 % pure water to the residents.

Contaminated water may contain bacteria, viruses, cysts, inorganic substances, dissolved salts and heavy metals. These are harmful to health and can cause severe diseases like diarrhoea, cholera etc.

In this situation, you must purify the water before drinking. When it comes to water purifiers, you can find three types of water purifiers in the Indian market. These are UF, UV and RO water purifiers respectively. Each of them has some advantages and disadvantages.

In order to choose the right water purifier for you, it is important that you have some knowledge about water purification technology. Since this is not a technical article, we will not discuss too much technology here. Instead, to make things easier, we will discuss what kind of water purifier is needed in which case and its advantages and disadvantages.


RO vs UV vs UF Water Purifiers

Let’s have a look at the table below to understand the primary difference between RO vs UV vs UF water purifier.

RO PurifierUV PurifierUF Purifier
Electricity Needed
Kill Bacteria and Viruses
Remove dead bodies of Bacteria and Viruses
Remove dissolved Toxic Elements
Works with Dirty Turbid Water


1. RO (Reverse Osmosis) water purifier

RO water purifiers are devices that remove impurities from water by reverse osmosis technology. These types of water purifiers use a partially permeable membrane to purify the water. When water passes through this membrane, all the contaminants are removed.

When water is purified in this way, dissolved or undissolved particles, no matter how small in size, remain on the other side of the membrane. On the other hand, only purified water can pass towards the user.

The RO purifier comes in the category of the most reliable water purifier. It is worth mentioning here that only RO technology is capable of removing dissolved contaminants from water.


How does an RO purifier work?

You may remember that we studied osmosis in chemistry and biology classes.

Osmosis is a natural process where fluid moves from a low-density region to a high-density area when separated by a semi-permeable membrane.

Reverse osmosis is the exact opposite of osmosis. In this case, the fluid is transferred from the region of higher density to the area of lower density by applying pressure.

We already know that RO purifier filters water through a semi-permeable membrane. This membrane has numerous tiny pores that are no larger than 0.0006 microns in size. Only water molecules can pass through these small pores, and other contaminants in the water cannot pass through these pores due to their large size. So only pure water is supplied to the other side of the membrane.

This method removes all contaminants, be it mud, salt, dust, viruses or bacteria. Even molecules of dissolved toxins such as lead, arsenic, cadmium or fluoride are removed from the water by this method. That is why RO water purifier is considered as the most reliable water purifier in the world.

It should be noted that dissolved contaminants are considered as a slow poison. If you consume these contaminants, the side effects will not be immediate. Instead, drinking this Impure water for a long time will cause these contaminants to spread in your body over time. Eventually, you will be diagnosed with a severe illness such as cancer or irreversible organ damage.

First, you should check the TDS of your drinking water. If the TDS value is higher than the acceptable level, then the standard water purifier is ineligible. In this case, you need to install a RO water purifier in your home.

At this stage, you realize how thoroughly an RO purifier cleans almost all minerals from water. Undoubtedly, healthy minerals have to be sacrificed in this case. Modern RO water purifiers come with a mineralizer to fill this gap. The mineralizer restores healthy minerals into the water. This way, the RO purifier gives you pure and healthy drinking water.

Advantages of an RO Water Purifier

  • A UV water purifier can kill bacteria, viruses and other microorganisms. Still, it cannot get their dead bodies out of the water. An RO water purifier, on the other hand, kills all contaminants and removes their dead bodies from the water.
  • RO is the only available technology that can remove dissolved toxins from water such as pesticides, lead, cadmium, iron and arsenic. UV or UF technology, on the other hand, fails in this case.
  • Modern RO purifiers come with a TDS controller or mineralizer that enriches the water by adding healthy minerals. Other purifiers do not have such arrangements.
  • RO purifiers come with a storage tank that stores pure water. So you don’t have to worry about pure drinking water in case of a power outage.
  • The air pressure system automatically clears the funnel. It reduces the frequency of maintenance checks.
  • RO purification is the most reliable and trusted method in the world that can provide 100% safe and purified water.

Disadvantages of an RO Water Purifier

  • An RO purifier separates the purified water from the total water taken and rejects contaminated water, which is unfortunately wasted.
  • About 50% of the total water used in this process is rejected. It is not an environmentally friendly option, given the growing water crisis all over the world.
  • Electricity is a compulsion. An RO purifier cannot work without power.
  • Compared to other technology purifiers, the maintenance cost is higher for RO purifier.

Recommended Reading: RO (Reverse Osmosis) Water Purifiers – Pros and Cons


2. UV (Ultraviolet) water purifier     

UV water purifiers are devices that disinfect water with UV(ultraviolet) rays. This type of water purifier has an ultra-violet lamp inside the chamber that emits a germicidal wavelength. When water flows around it, UV rays kill harmful germs like viruses, bacteria etc. present in the water.

UV is a highly effective method that can disinfect water up to 99.9%


How does a UV water purifier work?

These types of water purifiers have a UV lamp attached to the chamber. When water flows through this chamber, pathogens, such as bacteria and viruses, take a deadly dose of UV rays that destroy the DNA of their cells and kills them.

Although the dead bodies of germs remain in the water, they can no longer reproduce and do us no further harm. Thus UV water purifier ensures 99.9% sterile drinking water.

Advantages of UV water purifier

  • It is a proven and reliable purification system that can disinfect water up to 99.9%.
  • These purifiers are easy to install, user friendly and automatic.
  • No special attention or manual intervention is required in this case.
  • A UV purifier system does not change the taste, odour, pH or conductivity of water.
  • UV water purifiers can provide instant purified water. In contrast, other water purifiers take longer to purify water.
  • Compared to an RO purifier, it is energy efficient and has lower operating costs.

Disadvantages of UV water purifier

  • UV water purifiers cannot remove dissolved impurities such as pesticides, arsenic, lead, cadmium and fluoride.
  • This technology effectively kills harmful germs such as viruses, bacteria, etc., but cannot remove their carcasses from the water.
  • The germicidal rays coming from the UV lamp have to target the germs present in the water. However, many barriers, including suspended visual solid and non-visual particulate matter, can affect UV performance.
  • Physical scale deposits in quartz sleeves caused by iron, manganese or calcium carbonate can interfere with the emission of adequate UV rays. That reduces the efficiency of the device.
  • UV water purifier cannot work without electricity.

Recommended Reading: UV (Ultra-Violet) Water Purifiers – Pros and Cons


3. UF (Ultra-filtration) water purifier

UF is a basic water purification technology that is somewhat similar to RO water purification technology. However, it is not as advanced as RO technology.

Like RO purifiers, UF water purifiers also work based on semi-permeable membranes. This membrane helps to remove contaminants from water molecules.

In this case, the hydrostatic force causes water to apply pressure to the membrane wall. This membrane has tiny holes through which water molecules can pass. But microscopic components and germs cannot pass through these pores due to their large size. Therefore, these pollutants separated from the water. That is how a UF water purifier provides you with purified drinking water.

This technology can successfully remove bacteria, viruses and turbidity from water.

Significantly, this whole purification process is natural. In this case, no chemicals are used, and no electricity is required. It also does not change the natural taste of the water. Moreover, the cost of purifying water in this method is very low as compared to other technologies.

Considering all these qualities, you may think that UF is probably the best technology for water purification. But it’s wrong, there’s a big drawback.

Groundwater pollution has increased dramatically in the last few years in various states of India. Excessive use of pesticides and uncontrolled industrial waste have led to heavy metal contamination in the water. Arsenic, lead, cadmium, mercury are some of them. All of these toxins are dissolved in water, which can lead to life-threatening diseases, such as cancer.

The biggest problem with UF water purifiers is that it fails to remove toxins dissolved in water such as arsenic, lead, cadmium, mercury, etc.

Advantages of UF water purifier

  • It removes impurities from your drinking water using only two basic filters, which makes it cheaper. Moreover, it works using gravity and natural water pressure. So, in this case, electricity is not required. It makes the cost even lower.
  • Clearing muddy water is a tough job. That is because the mud can be completely mixed into the water. UV water purifiers fail to purify the water in this case. But UF water purifiers can convert muddy water into clear water efficiently with the help of sediment filters and carbon filters.
  • A UF purifier does not contain much material and weighs much less. So it is much easier to carry. You can move it from one place to another without much effort.
  • UV models have an ultraviolet bulb that helps kill bacteria and viruses instantly. But over time the light of the bulb fades and loses efficiency. In this case, you need to buy a new bulb. So maintenance costs can be quite high. But all these things do not happen with any UF water purifier. They use conventional filters and the gravity factor to purify your water. So, you don’t have to spend a lot of money on maintenance.
  • A UF filter can give you cleaner water than boiling water. In the case of boiling water, the carcasses of germs remain in the water. But UF filters get them out of the water.
  • In the case of RO and UV purifiers, the installation process is quite complicated. You will need a technician for this. UF filters, on the other hand, do not have this problem. You can take it out of the packet and start using it immediately.
  • An RO purifier wastes enough water. In this case, 3 litres of water is wasted to get only 1 litre of pure water. The drinking water crisis is growing every day, so it is no less than a crime. On the contrary UF filter does not waste water. Therefore it is environmentally friendly.

Disadvantages of UV water purifier

  • The biggest disadvantage of the UF filter is that it cannot remove harmful salts and heavy metals dissolved in water. Toxic metalloids such as cadmium, arsenic, lead, mercury, etc. cause deadly diseases like cancer. Only RO purifier can get you rid of all these contaminants.

Recommended Reading: UF (Ultra-Filtration) Water Purifier – Pros and Cons


RO vs UV vs UF – What type of water purifier do you need?

Before buying the best water purifier, you should consider a few essential factors such as your drinking water source, type of contamination, TDS value, etc. In addition, you should have an idea about safe drinking water guideline.

We hope that at this stage, you have a clear idea of ​​the different types of water purification technologies, the basic differences between them and the different types of impurities in drinking water.

Now the question is, what kind of filter is suitable for your home?

1) First of all, you should get a TDS test of the water in your home. If you do not know how to do this, then you can read this article – How to check TDS of water.

Let’s have a look at the table below to understand the impurities and the ideal water purifier for that situation.

TDS ValueTurbid waterBacteriaIdeal purifier
Below 300 PPMUV
water purifier
Below 300 PPMUV+UF
water purifier
Over 300 ppmRO water Purifier
+ TDS controller
Over 300 ppmRO+UV+UF purifier
+ TDS controller

One thing to note here is that individual dissolved toxins are more important than the total value of TDS. For example, suppose you examine your drinking water and find that the total TDS value is below 300, which is generally considered safe to drink. However, that water may contain high amounts of arsenic, lead or mercury.

2) If there is any industry in your area, you should have a chemical test of your water to know the level of chemical impurities.

3) If you have any confusion, you should always choose the best water purifier with RO + UV + UF technology. These types of modern filters are able to provide you with safe drinking water by removing all kinds of impurities.

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