What is UF Water Purifier – Working, Benefits & Limitations

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In Brief: What is UF Water Purifier

UF water purifiers use ultrafiltration to remove impurities from water. In this process, water is pushed through a semipermeable membrane with microscopic pores. As a result, all contaminants larger than the pore size are retained and purified water is supplied to faucets. A UF water purifier is unable to remove dissolved salts, minerals, metals, and TDS.

The water that is supplied to most homes is not fit for drinking without some kind of filtration process. It could be muddy, carrying contaminants, or unpleasant in smell and taste.

There are various ways of purifying water that differ in their mechanisms. Some of these include reverse osmosis (RO), ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), and UV water purification.

These systems can be used in isolation or combination depending on the quality of the feed water. In this article, we explain how a UF water purifier works and when to use it.

What is a UF Water Purifier and How it Works

UF stands for ultra-filtration as this type of water purifier uses an ultra-filtration membrane. [1]

This thin membrane consists of many hollow fibers. The feed water flows either in the lumen of the fibers or inside the shell.

This membrane differs from the similar semi-permeable TFC membrane in RO systems on the basis of size. [2]

The UF membrane pores range from 0.005 microns to 0.1 microns. This is significantly larger than that of RO water purifiers.

Ultra-filtration removes many microscopic impurities from water such as bacteria, benzene, chlorine, pesticides, proteins, rust, and viruses.

It also gets rid of tastes, odors, and turbidity. UF water purifiers manage partial removal of algae, chloride, copper, lead, and mercury.

There are two kinds of UF water purifiers: a point-of-use system and a point-of-entry system. The former is a filtration system placed right before the faucet where purified water is needed.

The latter is a larger system placed at the water line before the water enters a house. In both types of systems, ultrafiltration works in the same way. The only difference is the number or size of the UF membranes used.

These membranes are a collection of numerous hollow fibers that have microscopic pores inside them. The pores create a semi-permeability that removes all contaminants larger than the pore size.

Since only the water and dissolved substances can pass through the pores, this removes all colloidal matter suspended in water. Water is pushed through the UF membrane and this can be done in two ways.

Either the water flows through the fibers to leave the contaminants on the outside with ultrafiltered water inside the lumen. Or, the opposite, with contaminants in the lumen and ultrafiltered water outside.

This pressure of water against the membrane can be operated through a pump or with gravity. After filtration, water is passed through the faucet for use.

This water retains salts and minerals like calcium, sodium, and magnesium.

To get a visual demonstration of the ultrafiltration procedure, watch this informative video:

Benefits of a UF Water Purifier

There are quite a few advantages to using a UF water purifier at home. As compared to RO systems, which have a 1:3 wastewater ratio, UF systems are better for the planet.

They do not produce any wastewater at all. Another characteristic that makes them good for the environment is that they can run on little to no electricity.

Low water pressure or maintenance is not a big deal as UF water purifiers use gravity for the required pressure.

They can clean muddy water and the purified water is cleaner than boiled water. That’s because, in boiling, the carcasses of the dead microbes are retained in the water.

Ultrafiltration removes these microorganisms entirely.

UF water purifiers manage all this without using any chemicals or cleaning agents. They are a highly natural way of purifying water.

Limitations of a UF Water Purifier

There are a few limitations as well when it comes to using a UF water purifier. The microscopic pores may get rid of a large number of pollutants. However, dissolved materials are not effectively removed.

A UF system can only partially remove heavy metals like copper, lead, and mercury. These can be harmful to health especially when consumed by children with developing immune systems.

Ultrafiltration is ineffective in the removal of dissolved salts and minerals. It is also unable to reduce TDS levels of water. Though this is not dangerous to health, it can affect the aesthetic quality of water.

Overall, a UF water purifier alone isn’t that effective in water filtration as it can be in combination with other systems.

When to use a UF Water Purifier

A UF water purifier is a preferable choice when homeowners are concerned about saving water. This could be because of a shortage of water or restrictions placed by local authorities.

UF water filters are ideal for environment-conscious citizens too as it does not produce wastewater and can run without electricity.

A lot of people prefer retaining the salt and mineral content in water for health benefits. This maintains the pH levels of water and hence the body. For this purpose, ultrafiltration is a better choice than other filtration techniques.

It is also a good option for areas where the water supply is generally low on salts or TDS. To know if a UF water purifier is suitable for you, test your water supply and evaluate your preferences.


A UF water purifier uses ultrafiltration technology to remove contaminants from water. It does so by pushing water through a semipermeable membrane that filters out pollutants.

The pores of this membrane are microscopic so they retain all materials larger than the pore size. A UF water purifier can effectively remove bacteria, benzene, chlorine, pesticides, proteins, rust, and viruses.

It also gets rid of tastes, odors, and turbidity. These systems work using little to no electricity and produce no wastewater. They require very little maintenance and produce water cleaner than boiled water.

However, ultrafiltration cannot remove dissolved salts, TDS, and heavy metals. That’s why, in isolation, they are a good choice for homeowners who want to retain minerals. They are also ideal for areas that don’t have TDS/metal problems in their water supply.