Does Reverse Osmosis Remove (Kill) Viruses? Find Out Here!
Written by: Gene Fitzgerald // Last Updated: May 9, 2023
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Reverse osmosis has proven to be an effective water purification method.
It clears out physical and chemical contaminants providing clean water for consumption.
But does reverse osmosis also remove viruses or even kill them? Let’s find out!
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Key Takeaways
- Reverse osmosis can remove any viruses from water, like the enterovirus and the norovirus.
- It is generally not recommended to use reverse osmosis water purification for removing viruses, though.
- Reverse osmosis does not kill viruses in water. To destroy viruses in water, you must use UV or chemical disinfection, or boiling.
Does Reverse Osmosis Remove Viruses?
So, does reverse osmosis remove viruses from water? Yes, reverse osmosis removes viruses from water.
A reverse osmosis system uses of a semipermeable membrane with a pore size of around 0.1 nm (nanometer). Viruses average 20-25 nm in size.
Because viruses are larger than the RO membrane’s pores, they cannot diffuse through the membrane during filtration and are washed down the drain.
Viruses that can be removed by reverse osmosis water purification include the enterovirus, the norovirus, and the adenovirus.
Note: Although reverse osmosis can remove viruses from water, it’s not designed for it. After a while, the viruses and possibly other pathogens can grow and accumulate on the RO membrane, eventually slipping into the water and contaminating it. In order to kill any microorganisms, your safest bet is to combine an RO system with a UV water purifier or chlorination.
Does Reverse Osmosis Kill Viruses?
Reverse osmosis is an impressive water purification method, but it has its limits. Reverse osmosis does not kill viruses in water; it only rejects them.
To kill the viruses in your water, you would need to combine your RO system with a UV water purifier for example. The UV light would kill any viruses by disrupting their DNA and stopping them from multiplying. UV purifiers eliminate up to 99.99% of viruses in water.
Further Reading:
Types of Viruses Present in Tap/Well Water
Depending on where you live, common viruses in tap and well water include
- Enterovirus
- Norovirus
- Rotavirus
- Hepatitis A
- Adenovirus
These viruses are responsible for several gastrointestinal illnesses, headaches, fever, and can also lead to respiratory issues if left untreated. Hepatitis A attacks the liver.
Norovirus
The norovirus is a highly contagious virus that causes nausea, vomiting, diarrhea, and stomach pain. Anyone can get norovirus if they’re exposed to contaminated water or food tainted with fecal matter.
Adenovirus
The adenovirus causes mild respiratory illnesses like the common cold. It can also cause bronchitis, pneumonia, pink eye, skin rash, and bladder and bowel infection.
Adenovirus is largely present in groundwater, and as a result, it’s common in well water.
Rotavirus
The rotavirus is the leading cause of viral gastroenteritis worldwide and has been responsible for several waterborne outbreaks. It’s another virus commonly found in drinking water.
Rotavirus is particularly dangerous to the young, elderly, and immunocompromised.
Hepatitis A
The hepatitis A virus causes hepatitis A, a liver infection characterized by inflammation.
The virus is found in contaminated food and water and is easily transmittable through direct contact.
Symptoms of hepatitis A include loss of appetite, fever, diarrhea, and nausea.
Enterovirus
When infected fecal matter enters through sewage overflows or malfunctioning sewage systems, water can become contaminated with the enterovirus.
Signs of enterovirus infections include a runny nose, skin rash, cough, sneezing, mouth blisters, cough, and body aches.
Health Effects
Waterborne illnesses from viruses in water can lead to all kinds of symptoms. These include:
- Diarrhea
- Nausea
- Dizziness
- Fever
- Dehydration
- Abdominal cramps
- Headaches
- Respiratory distress
- Skin rash
- Bladder infection
- Pink eye
- Cough
- Mouth blisters
- Muscle ache
- Organ damage
What Else Does a Reverse Osmosis System Remove?
Aside from viruses, RO systems remove a broad range of contaminants from water. They include:
- Sediment and silt
- Total dissolved solids (TDS)
- Chlorine/chloramine and disinfection byproducts
- Heavy metals, including mercury, lead, and cadmium
- Bacteria
- Pesticides and herbicides
- Transition metals (nickel, iron, chromium, etc.)
- Minerals and salts (calcium, magnesium, sodium, potassium, fluoride)
Bacteria and Other Pathogens
Reverse osmosis also removes bacteria and other pathogens from water.
As mentioned before, the reverse osmosis membrane has an approximate pore size of 0.1 nm — small enough to prevent bacteria, viruses, and other pathogens from making their way through it.
Bacteria and cysts that are removed by reverse osmosis include:
- Escherichia coli (E. Coli) and other coliform bacteria
- Campylobacter jejuni
- Salmonella typhimurium
- Pseudomonas aeruginosa
- Listeria monocytogenes
- Cryptosporidium
- Legionella
- Shigella
- Giardia lamblia
Other Ways to Remove Viruses from Water
If you’re not interested in using an RO/UV combination, these other methods can help you remove viruses from your water:
- Boiling: Boiling is the oldest and surest way to kill viruses in water. It also kills other disease-causing organisms like bacteria and parasites. Boiled water sometimes tastes flat. To remedy this, pour your freshly boiled water from one container to another, and allow it to stand for a few hours. You could also improve the taste by adding a pinch of salt to every quarter gallon of boiled water. After purifying your water, store it in a clean, tight-lid container and keep it tightly shut.
- Chemical disinfection: If you don’t want to boil your water, the next best option is to use a chemical disinfectant. The most popular chemical disinfectants are chlorine and iodine. While chemical disinfectants work, they’re not as effective as boiling and sometimes fail to kill resistant germs like giardia and cryptosporidium.
- Distillation: This is another way to get clean drinking water at home. A water distiller is used in this process. The distiller boils water until it evaporates, and then it cools and condenses the gas into purified liquid. Distillation is a thorough treatment technique that guarantees 100% pure water. It removes all disease-causing viruses (pathogens) and chemical impurities like lead and chlorine. Depending on the model, you can find a water distiller for $100-300.
If you have any thoughts about the question, can reverse osmosis remove viruses, please don’t hesitate to leave a comment below!
About the Author Gene Fitzgerald
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