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What is a Ceramic Filter and How Does It Work?

Posted by John Woodard on March 11, 2019

Ceramic water filters are a versatile method of water filtration that use natural media to eliminate bacteria and sediment from drinking water. Ceramic filters range from under-sink installations for point-of-use consumption to portable filters you can take on camping trips to stay hydrated on your adventures. Ceramic water filters are popular choices because of their affordability, longevity, and powerful filtration properties.

Ceramic water filters are one of the oldest methods of water filtration on the market. In 1827, inventor and potter Henry Doulton discovered that filtering water through porous ceramic media would remove waterborne pathogens like cholera from drinking water. Commissioned by Queen Victoria, Doulton created a royal gravity-fed water filter that joined the elegance of hand-crafted pottery with his revolutionary water filtration technology. Ceramic water filters have been a staple of the water filter market ever since.

What is a ceramic filtration system? 

A ceramic filtration system uses tiny pores on a ceramic surface to filter bacteria and sediment out of drinking water. It is an affordable and versatile water filtration system that can be installed in households or used as a portable filtration device. 

A ceramic filtration system uses a natural ceramic media as the heart of a water filtration process. The ceramic filter cartridgeoften referred to as a ceramic filter candle, processes the water and removes contaminants through a network of pores. Ceramic filtration systems exist in a variety of applications. They can be gravity-fed, under-sink, countertop, or in some instances, used for a whole house or even light industrial processes. 

Furthermore, a ceramic filtration system is one of the most economical filtration options available. An entire point-of-use ceramic (POU) system usually falls in the price range of $100-$200. This is a far more environmentally friendly option than relying on bottled water, and significantly cheaper than many other filtration systems. The ceramic filters themselves can be cleaned and reused, reducing the number of replacement filters that need to be purchased. The gravity-fed models are portable and require no electricity to operate.

How does a ceramic filter work?

Ceramic water filters work by allowing water to flow through the millions of tiny pores on the casing of the ceramic cartridge. These pores, a half micron in size, trap impurities as the water passes through them. The inside of the filter is a convoluted maze of sharp angles designed to further catch any particles that have penetrated the exterior surface. Owing to the minute size of the pores and complexity of the filter, the water percolation through a ceramic filter is very fine particulate filtration, eliminating a host of contaminants like bacteria and sediment.

This system of filtration imitates part of the Earth’s natural water purification process. Just as water from aquifers seeps through layers of rock in the earth’s surface as it makes its way to streams, the water in a ceramic filter permeates natural media to rid itself of impurities.

What is in a ceramic filter candle?

Ceramic often works in tandem with other filtration media to enhance the quality of the water. Most commonly, ceramic filter candles will be made with an internal activated carbon core. The carbon core increases the adsorption capabilities of the filter. 

The ceramic is also often impregnated with silver ions, giving the filter strong bacteriostatic and self-sterilizing properties. These silver ions repel bacterial growth, preventing mold and algae from developing on the surface of the filter.

With the carbon inside and silver-impregnated ceramic, you've got a filter that can get rid of a list of chemical contaminants as well as living organisms.

When to use a ceramic filter

The most common application for ceramic water filters is for point-of-use drinking water. Because of its 0.5 micron filtration, simple upkeep, and low cost, they make excellent countertop or under-sink filters in households. The gravity-fed filters can provide you with clean water in your kitchen and be taken on hiking and camping trips. If installed with the proper cartridge, you can pour stream water into the filter and make it drinkable. Ceramic filters are also ideal for anywhere where space is limited, like an apartment or RV. There are also double open-ended ceramic filters that can be inserted into any standard 10-inch water filter housing and used in conjunction with other filters, like a sediment filter or anti-scale filter.

What does a ceramic filter remove? 

Ceramic alone is a powerful filter and handily removes many contaminants. The extent of the filtration varies, and will depend on what additional filtration media the ceramic candle contains.

  • Bacteria: Ceramic filters are quite effective at removing bacteria from water. Few bacteria are smaller than one micron in size. Unable to pass through the pores, the bacteria are filtered out as the water seeps through the ceramic filter. Ceramic filters rid water of about 99% of pathogenic bacteria, including E. coli, shigella, and salmonella. Microbial cysts like Giardia and Cryptosporidium are also too large to pass through the filters and are easily removed by the ceramic shell. The silver ion impregnation makes ceramic filtration especially advantageous to those with microbiologically unsafe drinking water. Silver ions are toxic to bacteria, further nullifying bacterial contaminants and preserving the cleanliness of the filter’s surface. 
  • Sediment: Particulate matter like dirt, debris, and rust is also effectively filtered out by the ceramic filter’s porous surface.   
  • Turbidity: Turbidity is cloudiness caused by suspended particles in the water. This turns your water unappetizing shades of yellow and brown. Ceramic filters are adept at removing the murky coloration and restoring the water to a crystal clear state. 

Ceramic filters with activated carbon: 

  • Chlorine: Chlorine is present in most city water as it is used in the municipal purification process. Chlorine leaves water with a bitter and chemical taste and unpleasant smell. The activated carbon reduces both chlorine and chloramines in water, restoring your water’s fresh flavor. 
  • VOCs: Volatile organic compounds, or VOCs, include a wide array of chemical contaminants that make their way into water by way of everything from agricultural runoff to consumer products like paints and pesticides. These compounds are all carbon-based, and ceramic filters with carbon cores will greatly reduce the levels of VOCs in your water.

Ceramic filters with ion exchange resin:

  • Heavy Metals: If the ceramic element contains an ion exchange resin, heavy metals like lead, mercury, copper and zinc are greatly reduced in the water.

Multistage ceramic filters 

Ceramic filters often combine all these elements for a comprehensive purification process. The water enters through the ceramic impregnated by silver ions, filtering particulate matter and repelling bacterial growth, then flows through a layer of activated carbon followed by the ion exchange resin.

ceramic filter diagram

 Here are some ceramic filter candles that offer this multistage filtration power:


What ceramic filters don’t remove:

  • Minerals: Ceramic is a natural media filter, and does not add anything to the water during the filtration process. It also does not filter out minerals like calcium and magnesium, meaning there is no need to pair the filter with a remineralizer if you want to preserve the mineral quality of your water. If you are primarily concerned with reducing water hardness, a ceramic filter is not going to be effective. Instead, look into a water softener
  • Viruses: Viruses can be anywhere from .004 to .1 micron in size, making them difficult to remove by mechanical filtration alone. Though viruses often travel through water on larger particles that potentially could be removed by the ceramic membrane, a UV water purifier is much better alternative for reducing viruses in your water. 
  • TDS: Though it is great at reducing particles and organic matter, ceramic filters cannot remove dissolved particles. These total dissolved solids (TDS) are best addressed by a reverse osmosis system. However, this level of filtration is not needed by everyone, especially if you are predominantly looking for a simple point-of-use system to improve the quality and taste of water from your faucet. You should first conduct a water test to determine the extent of contaminants present in your water. 

To learn more about reverse osmosis and if it is the right fit for your needs, explore how a reverse osmosis system works

How to clean a ceramic filter

One of the benefits of a ceramic filter is that is can be cleaned and reused many times. As water is filtered through the ceramic, the filtered contaminants build up on the exterior of the ceramic candle, clogging the porous surface, and causing the water flow to slow down or stop entirely. When you notice this happening:

  1. Carefully remove the ceramic candle from the unit’s housing. Handle the candle gently, as ceramic is a fragile material and can crack if dropped.
  2. Scrub the filter under running water or in a bowl of water with a clean plastic brush, toothbrush, or soft scouring pad. Avoid soaps and detergents, or rough materials like steel wool. These will render you filter unusable. Brush away from the threaded mount to avoid contamination. You may consider covering the mount with a plastic to protect it. 
  3. After checking to ensure the sealing’s washer is properly seated, re-install the filter. 

When to replace your ceramic filter

Though ceramic filters can be cleaned many times before requiring replacement, it is important to keep in mind that the internal components of the filter may have a shorter lifespan than the ceramic. Carbon media is exhausted much faster than ceramic, so, to maintain an effective filtration system, do not allow the filter to run past it’s rated gallon capacity. If your ceramic cartridge contains no carbon, you can continue cleaning it until the water will no longer flow through. 

Comments 1-10 of 7

Thank you so much sharing a information about ceramic filters usage.

Punitha on March 27, 2023

Nice post. Thank you for posting something like this.

Adamou Sàrl on March 28, 2023

I will be filling the filter from a rain catchment container by hand What does “empty housing” mean? Is there no filter inside? I had one in the Peace Corps years ago and would like a similar one.

pat McMackin on July 26, 2022

Hi, Are ceramic water filters free from arsenic?

Thanks very much.

Rick Smith on February 23, 2021

Extremely helpful article. Thank you. As a senior, I would like good tasting water still with its minerals and no fluoride. Having a hard time figuring where to go to buy (if possible) an under the sink system for (possibly) less than $ 200. Could you steer me in the right direction? I would appreciate it so much.

Jacqueline Guizol on February 03, 2021

Thanks so much for the elaborate stuff. I wish you update me with more information on water treatment and the dos and don’t. Once again I say thank you very much.

Philip Nelson Baidoo on January 15, 2021
can the ceramic filer purify pond water to drink
Sergio Smith on July 31, 2020
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