Can Water Filters Remove Bacteria?

Water, especially drinking water, and bacteria are two things that should never go together at all. This is why water filtration and purification is highly encouraged, to prevent chances of infections from occurring. Water filtration is a two-step process which involves the actual filtration process and disinfection to remove contaminants such as coliform bacteria. In most countries, the standards do not allow the presence of any coliform bacteria in water. Examples of total coliform include fecal coliform and E. coli, which can be found in human and animal feces.

Filtration alone will not remove all harmful bacteria. Most water filtration systems have carbon filters, which remove organic compounds from your water, such as herbicides and pesticides. However, carbon filters on their own cannot remove dissolved inorganic contaminants and dangerous microorganisms. Viruses that are between 20-400 nanometers in size cannot also be removed by carbon filters.

Not all filters are created equal

Different water filters have different functions. However, no single filter can remove all types of contaminants 100%.

Filtration of contaminants highly depends on the number of contaminants, size of the contaminant particle and its charge in the water. Contaminants in this case, refers to bacterial components.

For carbon filters to remove bacteria, they have to work with other physical and chemical components such as iron, manganese and hydrogen sulfide. You will also need to consider addition of coagulants, adjustments to pH or chlorine concentration levels and other pre-treatment processes. The carbon filters must also be of high quality.

How can you ensure water filters remove bacteria?

For complete removal of bacteria through filtration and purification processes, four methods can be used which include microfiltration, ultrafiltration, nanofiltration and reverse osmosis system.

  • Microfiltration

A microfiltration filter usually has a pore size of approximately 0.1 micron (normal pore size ranges vary by filter from 0.05 to 5 micron).

The microfiltration process is very effective for removing protozoa, bacteria (including E.coli) and viruses. Its main limitation is that it is not quite effective for removing chemicals.

  • Ultrafiltration

The ultrafiltration process removes particles based on size, weight and is effective for removing protozoa and bacteria. However, it is moderately effective for viruses. It also has low effectiveness in removing chemicals.

  • Nanofiltration

Nanofiltration is very effective for removing protozoa, bacteria and viruses. However, it has a moderate effectiveness in removing chemicals.

  • Reverse osmosis system

Reverse osmosis system is a process that involves the reversing the flow of water in a natural process of osmosis so that water passes from a more concentrated solution to a more diluted solution through a semi-permeable membrane. Both pre and post-filters are included in the reverse osmosis membrane process itself.

The reverse osmosis system is highly effective for the removal of protozoa, bacteria, and viruses. It will also remove common chemical contaminants, metal ions and salts.


Your water filtration system will need constant maintenance to ensure its performance is maintained at optimal levels. Carbon filters will require regular filter replacements, to prevent build-up of bacteria and other contaminants in the system.








Taylor is an adrenaline junkie. If you do not find him writing for homewaterclense, he will be on his Harley; riding with the wind. He loves spending his time scaling the mountains, skydiving and if time allows he will be scuba diving at some ocean; his game for anything that will keep his blood pumping. Taylor lives on the mantra that life is not a dress rehearsal and so he makes good use of his time here on earth. He is married to a beautiful wife and they have two lovely children. A man of very little words; Taylor is the engine that keeps the website going.

Click Here to Leave a Comment Below 0 comments

Leave a Reply: