Water Filters That Remove Viruses – and the ones that kill them!


Distillation, nanofiltration, reverse osmosis and UltraViolet water treatment systems remove viruses from water. Ultrafiltration systems can also be moderately effective at removing viruses, depending on the pore size of the filter.

Viruses can easily contaminate our water supply and remain infectious for up to 10 months. Ideally, viruses should be removed from your water before you drink it, but not all water filters or purifiers can remove viruses from water.

This article discusses which types of water filters and water treatment systems will remove or kill viruses. There is also detailed information about the different types of viruses and how long they can survive in water and remain infectious – with some viruses able to survive up to 300 days! First, let’s cover how viruses get into our water and how to remove them.

How viruses get into drinking water

Viruses make their way into our water supply through contaminated water – usually water that is contaminated with feces.

There are many ways that feces can enter our water, but the most common ways are:

  • Agricultural runoff
  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted storm water runoff

Unbelievably, just 1 oz of feces from an infected person can contain as many as 280,000,000,000 viruses. 

It’s scary to think about how contaminated our drinking water can actually be! Not only that, but fecal contamination is also responsible for introducing nasty bacteria to your drinking water!!

In fact, nearly 25% of the world’s population is drinking fecally-contaminated water!Ref7

Viruses you can you get from water

A large number of viruses are waterborne – which means they can survive in water and infect anyone that drinks it.

As we discussed earlier, waterborne viruses typically enter our water supply through fecal contamination! That’s right – from feces being in our drinking water supply. Which is a totally disgusting thought!

Currently, there is no way to test for viruses in water. But, you can test for fecal contamination by testing for fecal coliform. Fecal coliform is a bacteria that is found in almost all mammal feces.

So, by testing for fecal coliform, you can find out if your water is contaminated by feces, the primary way that introduces viruses to water in the first place.

Viruses spread from water are able to infect anyone that drinks or even touches it – the water just has to come into contact with the eyes, nose or mouth.

The most common viruses you can get from water are:

  • Adenoviruses
  • Astrovirus
  • Enterovirus
  • Hepatitis A
  • Hepatitis E
  • Meningitis (viral)
  • Norovirus
  • Rotavirus

Adenovirus

Adenoviruses are really common. According to the CDC, they cause any of a number of symptoms, including cold-like symptoms, bronchitis, diarrhea, fever, sore throat, pneumonia, and even PINK EYE!!! (conjunctivitis).

While adenoviruses are waterborne, it is more likely you would get infected by breathing in another person’s sneeze or cough or touching surfaces or people with adenovirus on them and then touching your own face.

So… stop touching your face!

Astrovirus

Human astrovirus is a nasty virus that causes serious bouts of diarrhea.

Even worse is that it is a major cause of acute diarrhea in children worldwide Ref1. Although it can cause vomiting, headaches and fever as well.

Astrovirus appears just 2-3 days after infection, but thankfully it also only lasts 2-3 days.

Enterovirus

Enteroviruses are actually a group of viruses, which is made up of 2 different groups of viruses:

  • polio related
  • non-polio related

The poliovirus is very contagious and usually infects people through contaminated feces. In fact, according to the CDC…

“The virus can live in an infected person’s feces for many weeks”

centers for disease control and prevention

Thankfully, there are vaccines for poliovirus and after they began immunizations across the U.S. in 1955, it wasn’t long before Polio was completely eliminated from the U.S. by 1979. 

So, you don’t really have to worry about getting poliovirus from your drinking water. But what about the non-polio related enteroviruses?

Well, unfortunately the non-polio enteroviruses are the viruses to be concerned about. Because…

“non-polio enteroviruses are second only to cold viruses as the most common cause of viral infections in humans”

centers for disease control and prevention

These enteroviruses are found everywhere in the U.S., and across the world.

Enteroviruses can be found in all water supplies, but especially in wells. In fact, these viruses can be in any water that is contaminated by feces.

Remember, feces can enter the water supply by:

  • Flood waters
  • Sewage overflows
  • Sewage systems that are not working properly
  • Polluted storm water runoff

Hepatitis A

Hepatitis A is actually a contagious liver disease! The disease caused by the hepatitis A virus can last for a few weeks or a few MONTHS!

Hepatitis A is found across the U.S. and just like enteroviruses enter our water supply through contaminated feces.

Hepatitis E

The hepatitis E virus (HEV) is also a liver disease. But thankfully HEV is super rare in the U.S. Which is good news, since HEV causes:

  • Fever
  • Fatigue
  • Loss of appetite
  • Nausea
  • Vomiting
  • Abdominal pain
  • Jaundice
  • Dark urine
  • Clay-colored stool
  • Joint pain

And even death! Although, during an outbreak the case mortality rate is just 1%

Meningitis

There is actually a bacterium, viral and fungal form of meningitis!

However, viral meningitis is the most common type – but, fortunately it is less severe than bacterial meningitis.

Meningitis is inflammation of the lining of the brain and spinal cord. So, ‘viral meningitis’ just means it is inflammation caused by a virus (rather than bacteria or fungi)

The most common cause of viral meningitis is the non-polio related enteroviruses! It is also possible to get viral meningitis from the mumps, measles and flu viruses, but enteroviruses account for the vast majority of viral meningitis cases.

According to the CDC, the common symptoms of viral meningitis are:

  • Fever
  • Headache
  • Stiff neck
  • Eyes being more sensitive to light
  • Sleepiness or trouble waking up from sleep
  • Nausea
  • Irritability
  • Vomiting
  • Lack of appetite
  • Lethargy (a lack of energy)

Norovirus

You may have heard of norovirus by its old name – “Norwalk-like viruses” or NLV.

Noroviruses cause gastroenteritis, which is an intestinal illness.

Noroviruses are common across the whole of the U.S. and found in all sorts of water supplies – especially towns on groundwater or domestic wells.

Even though noroviruses are found in fecal contaminated water, they are responsible for outbreaks on cruise ships and in restaurants, camps and schools. That means our drinking water can become contaminated no matter where it is sourced from.

Rotavirus

These viruses got their name because they are wheel-shaped (“rota-“).

According to the CDC, rotavirus causes…

“… intestinal illnesses and are the most common cause of severe diarrhea among infants and children”.

centers for disease control and prevention

Thankfully in 2006, the rotavirus vaccine was introduced across the U.S. and drastically reduced infection rates. Which is a great thing, because rotaviruses still cause more than 600,000 children to die each year around the world.

Like most other waterborne viruses, rotavirus enters our water supply by fecal contamination. Something, I am sure we would all like to avoid.

Water-associated viruses

As well as the waterborne viruses there are insect-borne diseases that are associated with water, such as Dengue Fever. Dengue Fever is transmitted by mosquitoes that carry the Dengue virus!

The CDC says dengue fever causes

  • Aches and pains
  • Nausea
  • Rash
  • Vomiting

But severe dengue fever can cause shock, internal bleeding and even death.

How long viruses live in water

Viruses are only ever truly alive when they are living inside a host that they have infected. ‘Hosts’ come in the form of living cells – such as those belonging to humans.

So, the real question isn’t how long do viruses live in water, but rather how long can a virus survive in water – without a host for it to infect?

Well, like most things in life… it depends.

It depends on the

  1. Type of water
  2. Temperature of water
  3. Type of virus.

1. Type of water

Viruses survive for different amounts of time in different types of water, including disinfected tap water, surface water (e.g. rivers) and salt water. That’s because different types of water have different properties and microorganisms.

Take the salt in seawater for example. The salt is thought to result in a much faster reduction in infectious viruses, as opposed to freshwater, which has barely any salt in it.

Or take the microorganisms that live in our freshwater. The presence of microorganisms in our rivers and lakes has been shown to drastically reduce the survival time of a virus in water.

But this also means that disinfected water allows viruses to survive much longer. This is because all of the helpful microorganisms are killed during the disinfection process at our water treatment plants.

Unfortunately, that also means that if our water supply becomes contaminated with infected feces AFTER the treatment plants have disinfected our water then viruses would thrive, survive and spread much more efficiently – and could pose a real threat to public health.

Let’s hope that doesn’t happen!

2. Temperature of water

The temperature of the water also affects how long a virus can survive.

The cooler the water the longer a virus will survive. This is called a temperature effect.

It means the decay or true death of a virus is much faster at high temperatures.

And I’m not talking about extreme temperatures. Water at just 40°F (4.4°C) will allow viruses to survive for an incredibly long time. Whereas water temperatures of 68°F (20°C) will destroy a virus quite quickly.

Now we come to the most important factor in how long a virus will survive.

3. Type of virus

Check out the table below for a list of the most common types of waterborne viruses and how long each can survive in water – as tested by scientists at 68°F in freshwater.

VirusSurvival time in waterReference
Adenoviruses92-304 days*2
Astroviruses90 days3
Enterovirus (Poliovirus 1)41 days2
Hepatitis A56 days2
Hepatitis E56 days4
Norovirus100 days5
Rotavirus32 days6

*Adenoviruses are a group of viruses, where the survival time of each virus in water varies, with most surviving between 92 and 304 days.

Water filters that remove viruses

Unfortunately, the majority of water filters and purifiers can’t remove viruses from water. Especially faucet-mounted filters.

However, there are two water filter pitchers that can now remove certain viruses from water. These include the Clearly Filtered pitcher and the Epic Water Nano water filter pitcher.

Clearly Filtered Water Filter Pitcher

Virus% Removed
MS2 Phage99.9999
Rotavirus99.9999

Epic Water | Nano Water Filter Pitcher

Virus% Removed
MS2 Phage99.95

The list below shows which types of filters and purifiers are able to effectively remove viruses. We will go into each in more detail below.

Method of filtration or purificationRemoves viruses
Counter-Top Filters
Distillation
Faucet-mounted Filters
Microfiltration
Nanofiltration
Ultrafiltration✘ / ✔
Reverse Osmosis
UltraViolet
Water softeners

Distillation

Distillation is amazing at removing viruses.

During the distillation process, water is heated until it boils and turns to steam. This steam is then collected and cooled back into liquid water – ready for you to drink.

Now, most contaminants, such as metals or chemicals, are simply left behind when the water turns to steam. But not viruses. Distillation doesn’t just remove viruses it KILLS them.

So not only will distillation remove

  • Arsenic
  • Barium
  • Cadmium
  • Chromium
  • Lead
  • Nitrate
  • Sodium
  • Sulfate

But it will kill

  • Bacteria
  • Parasites

and most importantly

  • Viruses

Distillers are a simple way of effectively killing viruses in water. Just remember not to let the treated water sit for too long in the storage tank, otherwise bacteria can start to grow in it.

We recommend this Megahome distiller on Amazon as it’s relatively cheap and the glass storage tank looks good plus it’s slightly harder for bacteria to grow in it:

Nanofiltration

Nanofiltration is 1 of only 2 water filtration systems that physically remove viruses from water. All the other systems are water purifiers (e.g. distillation and UltraViolet systems) that don’t rely on filters.

According to the CDC…

“Nanofiltration has a very high effectiveness in removing viruses (for example, Enteric, Hepatitis A, Norovirus, Rotavirus)”

CENTERS FOR DISEASE CONTROL AND PREVENTION

Nanofilters usually have a pore size of 0.001 micron – I say usually because they can vary by up to 0.01 micron.

Small pore sizes mechanically stop viruses from passing through the nanofilter.

However, not all nanofilters are created equal.

If a nanofiltration system claims to remove viruses, then it should be certified to NSF standards 244 or P231. That way you know it has actually been tested to remove viruses!

NSF testing is not mandatory, but I figure if a company truly believes in their product, then they will take the time and spend the money to get certified.

Ultrafiltration

Ultrafiltration is a tricky one. While this method can remove some viruses, it can’t remove all of them.

In fact, the CDC says…

“Ultrafiltration has a moderate effectiveness in removing viruses”

CENTERS FOR DISEASE CONTROL AND PREVENTION

Don’t get me wrong… a ‘moderate effectiveness’ is better than not being effective at all. But you want to be able to trust your water filter system and, more importantly, trust the water you are drinking is clean and safe.

Ultrafiltration just doesn’t tick those boxes.

For your own peace of mind then I would choose one of the other ways to remove viruses that are more effective, such as:

  • Distillation
  • Nanofiltration
  • Reverse osmosis
  • UltraViolet

Reverse Osmosis

Reverse osmosis systems are one of the absolute best ways to purify water. These systems get rid of just about anything.

Reverse osmosis systems are able to remove such a large range of contaminants, including viruses because of the incredibly small pore size of the semi-permeable membrane.

According to the CDC…

“A reverse osmosis filter has a pore size of approximately 0.0001 micron”.

CENTERS FOR DISEASE CONTROL AND PREVENTION

That means the semi-permeable membrane of a reverse osmosis system has a pore size 10 times smaller than a nanofilter.

It’s hard to imagine anything making it through a reverse osmosis system… except for water of course.

Reverse osmosis systems should be tested to NSF-58 standards.

UltraViolet

Ultraviolet germicidal irradiation (UVGI) disinfects water by using UltraViolet light.

While there are 3 types of UltraViolet (UV) light:

  • UVA
  • UVB
  • UVC

It is UVC-light that is the most harmful to viruses. It is so harmful in fact, that it can kill any viruses (and bacteria) that are in water.

The UVC light is so potent that it kills viruses at a DNA level, completely disrupting their ability to function or repair themselves.

Just like nanofiltration and reverse osmosis systems, UltraViolet water treatment systems should be certified by the NSF to prove they can actually kill viruses.

Under the NSF these systems are called ‘UltraViolet Microbial Water Treatment Systems’ and have NSF/ANSI 55 certification.

These are labeled Class A or Class B systems.

  • Class A systems can inactivate pathogenic organisms using a UV dose at the energy wavelength of 254 nm (40 mJ/cm²).
  • Class B systems can inactivate non-pathogenic organisms using a lower UV dose at 16 mJ/cm².

Both large residential systems and small portable UltraViolet water treatment systems use UVC to disinfect water and can be NSF certified, so you can rest assured both are able to kill any viruses in your drinking water.

UV lights are added to Whole House Systems or Reverse Osmosis Systems after as the final filtration/sterilization stage to make sure the water is bacteria and virus free.

For Whole House Systems

You will need a UV system big enough to sterilize enough water for your whole house depending on demand.

Standard household flow rates in the U.S., measured as gallons per minute (GPM), are as follows:

  • Faucet: 2.0-2.2 GPM
  • Shower or Toilet: 1.0-2.5 GPM
  • Washing machine: 3.0-5.0 GPM
  • Dishwasher: 2.0-4.0 GPM

So, as an example, if you had 2 faucets running, the washing machine and dishwasher were on, plus someone was in the shower, you would need a UV system capable of processing about 15.9 GPM.

  • Faucet x 2 = 4.4 GPM
  • Washing machine = 5.0 GPM
  • Dishwasher = 4.0 GPM
  • Shower = 2.5 GPM
  • Total = 15.9 GPM

Most people will buy a UV water treatment system larger than what is needed, just to keep up with high demand periods. However, it really depends on your situation and size of your home or cabin – you may only need an 8.0 or 9.0 GPM UV system.

The example below from crystalquest.com is a 24 GPM Ultraviolet Water Sterilizer System that is perfect for those on well water or if you draw water from a lake.

Ultraviolet Water Sterilizer System | 24 GPM | Image courtesy of Crystalquest.com

For Reverse Osmosis Systems

Most Reverse Osmosis systems deliver purified water to just the kitchen. So, you will only need a UV system to accommodate the flow rate to one faucet, the dishwasher and possibly a refrigerator water dispenser / ice maker. It’s a bit cheaper for this kind of set up and you will probably only need an UltraViolet system of about 8 GPM.

This example from Crystal Quest is an 8 GPM Ultraviolet Inline Germicidal Water Sterilizer.

UV Inline Germicidal Water Sterilizer | 8.9 GPM | Image courtesy of crystalquest.com

Related Questions

How do you remove bacteria from water?

Distillation and UltraViolet water treatment systems are the only devices able to kill bacteria and remove them from water. UltraViolet systems that can remove bacteria have NSF/ANSI 55 certification. Other methods capable of removing some bacteria from water include boiling, and the addition of iodine or chlorine.

Water Purification Guide has more information on how to remove bacteria from water here.

Do water filters remove amoeba?

Water filters that have NSF-53 or NSF58 certification are able to remove amoeba from water. Other water filters that have an absolute pore size of 1 micron or smaller can also remove amoeba.

For all the information on amoeba in tap water and which brands of filters can remove amoeba check out this post.

References

1Jeong, H. S., Jeong, A., & Cheon, D. S. (2012). Epidemiology of astrovirus infection in childrenKorean journal of pediatrics55(3), 77.

2Enriquez, C. E., Hurst, C. J., & Gerba, C. P. (1995). Survival of the enteric adenoviruses 40 and 41 in tap, sea, and waste waterWater Research29(11), 2548-2553.

3Abad, F. X., Pinto, R. M., Villena, C., Gajardo, R., & Bosch, A. (1997). Astrovirus survival in drinking water. Appl. Environ. Microbiol.63(8), 3119-3122.

4Parashar, D., Khalkar, P., & Arankalle, V. A. (2011). Survival of hepatitis A and E viruses in soil samples. Clinical Microbiology and Infection17(11), E1-E4.

5Ngazoa, E. S., Fliss, I., & Jean, J. (2008). Quantitative study of persistence of human norovirus genome in water using TaqMan real‐time RT‐PCR. Journal of Applied Microbiology104(3), 707-715.

6Raphael, R. A., Sattar, S. A., & Springthorpe, V. S. (1985). Long-term survival of human rotavirus in raw and treated river water. Canadian Journal of Microbiology31(2), 124-128.

7Gall, A. M., Mariñas, B. J., Lu, Y., & Shisler, J. L. (2015). Waterborne viruses: a barrier to safe drinking water. PLoS pathogens11(6).

Theresa Orr

Theresa Orr is an Earth Scientist who specializes in determining past climates from rocks using geochemistry. Her passion for clean water drives her to breakdown the science to provide easy to understand information that everyone can read.

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