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Does Reverse Osmosis Remove Amoebas? [Complete Guide 2023]

Does Reverse Osmosis Remove Amoebas


Every several years, you are well aware of the news that people are getting infected or dying from brain-eating amoeba and other water-borne diseases. Francine Marciano-Cabral of Virginia Commonwealth University in Richmond and her colleagues discovered Naegleria fowleri, a directly fatal amoeba, in water throughout the plumbing of an Arizona home where two young boys had just died in 2003. The amoeba was responsible for the boys’ death from encephalitis, a brain infection.

 The world has a multitude of microorganisms that thrive in water, but have you ever come across the name brain-eating amoeba? Sounds scary, right? But don’t worry.

In this article, you will find all the information you need about amoebas and the answer to your question, ‘Do water filters remove amoebas?’ Spoiler alert: Not all filters remove amoebas, but reverse osmosis systems might be your ticket to safe, pure, and clean drinking water.

In short, this guide contains answers to the following questions:

  • Does reverse osmosis remove amoeba?
  • Does reverse osmosis remove amoeba from your drinking water?
  • How does reverse osmosis remove amoeba?
  • What is the prevention and control of amoebas?

Brain-Eating Amoeba

According to the CDC, the amoeba is a single-cell organism abundantly found in warm water, lakes, springs, and rivers.  Acanthamoeba spp, and Naegleria fowleri, Balamuthia mandrillaris are mitochondrial, eukaryotic bodies that occur extensively and can conceivably cause infections in humans and other animals. When it enters the human body, it produces a rare but fatal infection and inflammation in the brain, followed by destroying brain tissue by “eating” it. More than 30 species of the Naegleria genus are known to cause meningoencephalitis, with N. fowleri and Naegleria australiensis being the most virulent.  Every year, there are multiple cases worldwide with people dying due to water-borne illnesses and brain-eating amoeba. When people hear of such cases, they invest in bottled water, which can be expensive in the long run, but there is another solution: the whole house reverse osmosis filter. Reverse osmosis filtration is an effective way of eliminating harmful microorganisms from your drinking water, implying that reverse osmosis water is the safest water to drink,

Which water filter removes brain-eating amoeba?

Thomas and Nicholas Ashbolt, a scientist with the EPA’s National Exposure Research Laboratory, looked at drinking-water studies from Europe, the Middle East, the Americas, and Asia to assess the number of amoebas. Amoebas were found in all tap water samples tested in 19 of the 26 investigations.

Do water filters remove amoeba? If yes, which water filter is best for removing amoeba? Many other questions are frequently asked. Today, we will answer all your queries.

With the rising demand for drinking water in areas without freshwater supplies, many viable methods for resolving water contamination have been explored. Raw water reverse osmosis technology has proven to be a game-changing invention, making it easier to recover clean water from untreated water (seawater ). Reverse osmosis filtration technology has advanced significantly in recent years, allowing for the creation of systems that are both energy-efficient and high-yielding. The highest level of filtration available is reverse osmosis. Reverse osmosis removes amoeba, and all dissolved solids and inorganic compounds with a molecular weight larger than 100 are blocked by the RO membrane.

Before proceeding to find out how a home reverse osmosis filter or reverse osmosis filtration removes microorganisms, let’s explore what specifications and types of water filters remove brain-eating amoeba. It is not tricky, but it is hard to find any water filter that explicitly states it eliminates brain-eating amoeba. But if you know the specific standards that the CDC has set for water filters, you can quickly identify filters that remove the microorganisms.

The first thing to look out for is National Sanitation Foundation (NSF) certification. 

There are two types of NSF certification to look for, meaning these certifications are voluntary, and not every filter or reverse osmosis unit has it. The certifications include:

  • NSF 53 – this standard is related to whole house reverse osmosis systems or point-of-use whole house water filters.
  • NSF 58 – this standard is related to the point-of-use of reverse osmosis units.

These certifications mean that the company has put the filters through the testing institute of ANSI, but certification does not guarantee the filter’s ability to remove amoeba. The other thing to keep an eye out for is the pore size of the filter you choose to buy or are using, as pore size relates to the type of impurities the filter can remove.

Reverse osmosis filters and reverse osmosis units mainly contain membranes with pore sizes of different microns. According to CDC recommendations, an absolute micron pore size of 1 or less eliminates microorganisms like amoeba. Reverse osmosis systems contain membranes up to 0.001-micron size, which means reverse osmosis units are your best bet for having amoeba-free water.

What is a drinking reverse osmosis system?

The drinking water Reverse Osmosis (RO) system is the most advanced of all membrane filtration systems. It is used to filter out dissolved sediments and other giant molecules in the water purification process. It is a membrane-based technology that purifies water by separating dissolved particles from the input stream, producing permeate and reject streams for various residential and industrial uses.

Drinking water Reverse osmosis system can remove a wide range of dissolved and suspended species from water, including bacteria, and is utilized in industrial and potable water production. Consequently, the solute is trapped on the pressured side of the membrane while the pure solvent is permitted to flow through. Large molecules or ions should not be allowed to flow through the pores (holes) of the membrane, while smaller components of the solution (such as solvent molecules) should be allowed to pass freely.


The drinking water Reverse Osmosis Process is based on a simple principle. RO is a physical technique that removes salts from water using the osmosis phenomenon or the difference in osmotic pressure between saltwater and clean water. RO is a pressure-driven membrane process that separates two water streams, rich in salt and low in salt, by forcing a feed stream across a semi-permeable membrane.
When the applied pressure is greater than the osmotic pressure, water will flow through the membranes a result, the permeate stream has low salt content, while the feed side has a concentrated brine. You can install countertop RO systems or undersink water filters according to the point of use.

Reverse Osmosis Major System

The four primary systems of a reverse osmosis desalination plant are:

(a) Pretreatment: it is supplied to remove any suspended particles to prevent salt precipitation or microbiological development on the membranes. Pretreatments might include traditional procedures such as chemical feeding, coagulation/flocculation/sedimentation, and sand filtration, as well as membrane processes such as microfiltration (MF) and ultrafiltration (UF).

(b) high-pressure pumps: provide the necessary pressure to allow water to flow through the membrane while the salt is rejected. Brackish water has a pressure of 17 to 27 bars, whereas seawater has 52 to 69 bars.

(c) Membrane systems: are a pressure vessel and a semi-permeable membrane that allows feed water to pass through. Spiral winding and hollow fiber RO membranes are the two most common forms of desalination membranes.

(d) Post-treatment: Depending on the permeate’s water quality and intended application, post-treatment may include pH adjustments and disinfection.

Membranes are the two most common forms of desalination membranes.

(d) Post-treatment

Reverse Osmosis System Advantages

The following are some of the advantages of reverse osmosis for dilute aqueous wastewater treatment:

  •  House Reverse Osmosis systems are simple to build and run, have low maintenance needs, and are modular, making system expansion straightforward.
  •  Reverse osmosis membrane techniques can remove both organic and inorganic contaminants at the same time.
  • When compared to other technologies, RO systems use less energy.
  • RO systems allow for the recovery and recycling of waste process streams while having no impact on the recovered substance.
  • The reverse osmosis process’ modular construction provides more flexibility in desalination facilities with a wide variety of capacities.
  • The particular energy demand is quite low. Product 3-9.4 kw/h/m3.

Does reverse osmosis remove amoeba from drinking water?

What does a 0.5-micron water filter remove? Or ”Does running your water through a reverse osmosis filter eliminate amoebas from it? Yes, your reverse osmosis filter has a semi-permeable RO membrane with a micron size of less than one and filters out all the impurities, including amoebas. The removal of contaminants means that your reverse osmosis water is safe and fresh to drink. 

Your reverse osmosis system drains and discards out the wastewater containing all the impurities. Only fresh and clean water is poured out for consumption. You can always add an extra UV filter with your reverse osmosis filtration to permanently sterilize the harmful microorganisms. 

The technique has been praised across the world as a safe and cost-effective method of purifying drinking water. Nitrate, sodium, cryptosporidium, fluoride, sulfides, giardia, arsenic, mercury, uranium, radium, and lead efficiently remove dissolved compounds and heavy metals. As water flows through thin, semi-permeable membranes, it is also effective in removing dangerous germs and chloride. As a result, it’s essential to keep up with the latest advances in reverse osmosis membranes.

The current focus has been on developing RO membranes with increased flux and salt rejection, chlorine tolerance, fouling resistance, and thermal stability.

On the other hand, chlorination is very sensitive to Naegleria and is suggested as an appropriate disinfection method.

How does reverse osmosis remove amoeba from water?

Now we know that reverse osmosis removes amoebas from water; let’s see how reverse osmosis filtration removes amoebas. Following the American Center for Disease Control, reverse osmosis units have filters with micron sizes of up to 0.0001. For a reverse osmosis filter with such a small micron size, it can filter micropollutants and microorganisms. 

The size of amoeba typically ranges from 2 microns to 5000 microns, meaning that drinking water reverses osmosis systems and reverse osmosis units filter anything more significant than the size of 0.0001 microns, making your reverse osmosis water is amoeba-free. You can never be more cautious, so you can add a UV filter, as suggested above, to make your reverse osmosis water safer.

Reverse osmosis removes around 97-98 percent of dissolved ions and 99 percent of other pollutants from water. Permeate is the name given to the cleansed water that exits the system.

Suppose you are interested in reading more about reverse osmosis filtration systems or make yourself aware of the best drinking water reverse osmosis systems on the market. In that case, you should check out our ultimate guide to the best reverse osmosis water filters.

Effects of Drinking Amoeba-Containing Water

If you don’t have a whole house reverse osmosis filtration system, make sure you have small-scale reverse osmosis units to provide you and your family with clean reverse osmosis water, as the effects of drinking amoeba-containing water are life-threatening and fatal.

Most people get infected by the microorganism because they ingest it through their mouth or nose when they come into contact with the infected water.  Coming in contact with infected water causes the fatal disease called primary amoebic meningoencephalitis (PAM). CDC states the following

symptoms of ingesting brain-eating amoeba:

  • headache
  • nausea
  • vomitings
  • fever

Later symptoms include:

  • stiff neck
  • confusion
  • loss of balance
  • seizures
  • hallucinations

The symptoms are set in 5-7 days after being infected, and death also occurs 10-12 days after the onset of symptoms. Considering how common brain-eating amoeba is in our environment, everyone needs to ensure no ingestion of the microorganisms since there is no cure for PAM.

Prevention And Control

The fascinating thing about brain-eating amoeba is that it only affects you if you ingest contaminated water through your nose. But primary amoebic meningoencephalitis (PAM) does not have any cure, which means you have to make sure there is no risk of contracting PAM entirely. 

Brain-eating amoeba is present in warm water lakes, rivers, and springs. These are where it is impossible to use reverse osmosis systems and reverse osmosis units to remove amoeba, so you have to ensure that your contact with such water sources is minimal. For people who swim in freshwater lakes, the CDC suggests reducing your contact with water by:

  • holding your nose shut
  • not putting your head underwater
  • make sure there is no ingestion of water through the nose

People who do not go swimming in freshwater lakes should ensure that when rinsing their sinuses or putting water up to their nose, the water they use should be reverse osmosis water or bottled water. Since reverse osmosis systems do remove amoeba, RO units are the best bet for prevention and control. 


Because the method of reverse osmosis system removes amoeba plus it is efficient at removing dissolved compounds, heavy metals, dangerous bacteria, and chlorine from water as it passes through thin semi-permeable membranes, it has been welcomed by the globe as a safe and inexpensive approach to clean drinking water. RO is also environmentally friendly since it does not require electricity; all it needs is enough water pressure to power it through the whole process. As a result, membrane maintenance and cleaning should be prioritized, and a broad search for multi-functional membrane materials with increased permeability high ion, and organic pollutants rejection.


Some other questions’ answers for our readers that might be helpful for reading.

Does the Reverse osmosis system need cleaning?

A desalination facility would not be complete without a cleaning system. Membranes can get polluted with pollutants such as colloids, biofilms, and biological materials after being used for a while. These pollutants can be absorbed into the membrane surface and the pipes of the membrane system, lowering the system’s performance, and the pollutants may be severely harmed. That is why you should clean the RO system after some time.

How to protect yourself from brain-eating amoeba?

As suggested by the CDC, the best way is to ensure no personal contact with freshwater lakes and springs. These places are where brain-eating amoebas are born. In any case, where there is contact, you should make sure there is no ingestion of the water through the nose.
If your primary water source is from a freshwater lake or spring, you should invest in reverse osmosis filtration. As highlighted above, reverse osmosis units and drinking water reverse osmosis systems are the most efficient in filtering water for you and your family.

Does reverse osmosis remove amoebas from tap water?

The answer to this question is the same as it was to does reverse osmosis removes amoebas. Yes, the reverse osmosis filter in the reverse osmosis units has small pore sizes to remove every harmful contaminant. 

What does a 0.5-micron water filter remove?

Most reverse osmosis filtration systems have membranes with pore sizes of up to 0.001 microns, but some other filters have a greater micron size of up to 0.5. The filters with 0.5-micron size removed:

  • Sand, sediments, and silt
  • Chlorine, foul odor, and taste
  • Lead and other heavy metals
  • Cysts and giardia cryptosporidium
  • Do water filters remove amoeba?

    Now that we have answered whether reverse osmosis removes amoeba, the other question is whether water filters other than reverse osmosis filtration remove brain-eating amoeba. Water filters that are NSF certified and have filters with a micron size of less than one are trusted to remove amoeba from your water.

    Do Brita filters remove giardia?

    In short, no. Brita filters are not structured to remove biological contaminants such as giardia from your water. They are only designed to eliminate chemicals, odors, and foul tastes from your water. To ensure adequate filtration of giardia or amoeba, invest in reverse osmosis filtration.

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