What is a Ceramic Filter and How Does It Work?

Posted by
John Woodard on December 11, 2023

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. In this article, you can discover answers to common questions about ceramic water filtration.

What is a ceramic filter?

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

ceramic filtration system uses a natural ceramic media as the heart of a water filtration process. The ceramic filter cartridge, often 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. 

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, one-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 catch any particles that have penetrated the exterior surface. Because of 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 a ceramic filter made of?

In most cases, ceramic filter candles are 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 a carbon core and silver-impregnated ceramic, you have a filter that can reduce a list of chemical contaminants as well as living organisms.

Where are ceramic filters used?

Ceramic filters can be used in under-sink installations, other point-of-use applications, or as portable filters you can take on camping trips or elsewhere. The most common application for ceramic water filters is point-of-use drinking water. Because of its 0.5 micron filtration, simple upkeep, and low cost, a ceramic filter makes an excellent countertop or under-sink filter 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. A double open-ended ceramic filter 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. The main categories of contaminants that basic ceramic filters remove are bacteria, sediment, and turbidity.

  • 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, such as 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 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 adeptly remove the murky coloration from water and restore its clarity. 
  • Chlorine (if filter contains activated carbon): Chlorine is present in most city water because it is used in the municipal purification process. Chlorine leaves water with a bitter chemically taste and an unpleasant smell. The activated carbon reduces both chlorine and chloramines in water, restoring your water’s fresh flavor. 
  • VOCs (if filter contains activated carbon): 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.
  • Heavy Metals (if filter contains ion exchange resin): If the ceramic element contains an ion exchange resin, heavy metals like lead, mercury, copper, and zinc are greatly reduced in the water.

What is a multistage ceramic filter?

A multistage ceramic filter combines silver-impregnated ceramic, activated carbon, and ion exchange resin. All of these together form 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

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 a 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. 

Learn more: What is a reverse osmosis system and how does it work?

How much do ceramic filters cost?

Ceramic filters are one of the most economical filtration options available. An entire point-of-use ceramic (POU) system usually falls in the price range of $100 to $200. Ceramic filters are 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 to clean a ceramic filter

One of the benefits of a ceramic filter is that it 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, clean the ceramic filter by following the below steps:

  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, detergents, and rough materials like steel wool.These will render your filter unusable. Brush away from the threaded mount to avoid contamination. You may consider covering the mount with plastic to protect it. 
  3. After checking to ensure the sealing’s washer is properly seated, re-install the filter. 

When to replace a 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 its rated capacity. If your ceramic cartridge contains no carbon, you can continue cleaning it until water no longer flows through it. 


If you have any additional questions, please do not hesitate to contact us.


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