Can Water Filters Remove Viruses?

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Unless you're in the health profession, you probably never gave a whole lot of thought to viruses up until early 2020.

Then the Coronavirus came on the scene, and that's all you see and hear about everywhere you turn. Crazy times we live in!

In light of all this concern about staying healthy, you might be wondering about your drinking water. Is there any way I could catch a virus from it?

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Well, let me assure you right off the bat - if you live in the United States, you most likely have nothing to worry about.

Here's what the EPA is saying:

EPA recommends that Americans continue to use and drink tap water as usual. The World Health Organization (WHO) has stated that the, “presence of the COVID-19 virus has not been detected in drinking-water supplies and based on current evidence the risk to water supplies is low.”

That's not to say that it's impossible for water to be contaminated with a virus. It can happen.

So, if you're one of those people who wants to be extra extra sure that your water is free of viruses, this article is for you.

What is a virus?

By definition, a virus is a microorganism generally ranging in size from 0.0004 to 0.1 micron. That's about one hundred times smaller than bacteria.

(The COVID-19 [Novel Coronavirus] is approximately 0.125 micron, by the way.)

A virus can't grow or reproduce in isolation. It survives by invading living cells and using their chemical machinery to survive and replicate.

How are viruses transmitted?

The main ways that viruses spread between people is through touch, saliva, or through the air. So that means that just breathing the same air can transmit a virus if you're in close proximity to someone else.

Viruses can also spread by indirect contact. In other words, if an infected person touches an object - like a doorknob - and you touch it, you could pick up the virus yourself. But there's a time limit, thank goodness. They generally only live two to three days on hard surfaces.

Can viruses survive in water?

Yes, they can.

But it's highly unlikely that you'd find viruses in drinking water here in the United States. That's because municipal water suppliers chlorinate the water to kill bacteria, viruses and other microorganisms.

Of course, well water could possibly be contaminated with viruses. But, again, that would be rare. If you're concerned, you could have your well tested and disinfect it if there's a problem.

Even though it's unlikely that you have viruses in your drinking water, you may want to add an extra layer of protection. You can do that by using one of the water treatment methods listed below.

What types of home water treatment will remove viruses?

There are lots of different ways to filter or treat your drinking water, but only a few methods are reliable for dealing with viruses. 

1. Boiling

pot of boiling water on stove

Boiling your water for one minute will kill any microbiological contaminants lurking in there. That includes viruses, bacteria and parasites.

You'll probably only want to use this method in an emergency situation, though. 

2. Filtration

Some filters remove viruses, and others don't. It depends on the size of the pores in the filter element. It has to be small enough to block the passage of viruses into the holding container.

carbon water filter cartridges and glass of water

There are three recognized levels of water filtration:

  • Microfiltration - pore size of approximately 0.1 micron
  • Ultrafiltration - pore size of approximately 0.01 micron
  • Nanofiltration - pore size of approximately 0.001 micron

As you can probably guess, nanofilters are the best for filtering viruses, as well as bacteria and protozoa. The CDC rates nanofiltration as highly effective for all microorganisms.

Ultrafiltration is moderately effective for viruses and highly effective for protozoa and bacteria

Microfiltration is not effective for viruses and moderately effective for bacteria and protozoa, according to the CDC. That's because most viruses are 0.1 micron or smaller.

Water filter brands I've reviewed that claim to remove viruses include these (click the links to go to the reviews):

A word about micron rating-

Sometimes when you read about different water filters, you'll see discussions about the micron rating. Just to warn you, this can be confusing and even unhelpful at times.

That's because you have what are called nominal ratings and absolute ratings, and one brand may report one and not the other. Plus, there is a US standard and an international standard, and you might not know which standard the brand is using. 

So if you're trying to compare them, you don't know if you're comparing apples to apples or apples to oranges.

I told you it was confusing!

That's why I rely on third party lab test results on the filters if I want to know how the filter performs. As consumers, I think that's the best we can do.

3. Reverse Osmosis

reverse osmosis system

With a filter pore size of about 0.0001 micron, reverse osmosis is even better than nanofiltration at filtering out viruses.

The CDC calls its performance very highly effective

Reverse osmosis is also very highly effective in removing other microbiologicals and common chemical contaminants.

So, if you want an all-around powerful filtration method for your water, you might want to consider reverse osmosis.

Just be aware that there are drawbacks. For instance, as part of the process, some water is always wasted, although the amount can vary from model to model.

For more information, please see my review of the best reverse osmosis systems.

4. Distillation

In distillation, you heat water to the boiling point and then collect the water vapor as it condenses and returns to a liquid state.

What you're actually doing is removing the water from the contaminants. Those get left behind in the container that held the boiling water.

Like reverse osmosis, distillation is considered very highly effective in removing viruses and other microbiologicals, along with most chemical contaminants.

It might sound complicated, but it's not. You don't need a laboratory to do it, either. There are plenty of water distillation systems available to purchase for your home.

To learn more about home water distillers, you can read my review here.

5. Ultraviolet treatment

Some water filter systems use a combination of carbon filtration with ultraviolet light.

The carbon filter removes many organic and chemical contaminants, and then the ultraviolet light disinfects the water by killing any microorganisms present.

Ultraviolet light is considered highly effective in removing viruses and very highly effective for bacteria and protozoa.

Conclusion

So, to sum it all up - 

  • If you're looking for the best way to remove viruses from drinking water, your best bets are either reverse osmosis or distillation.
  • Carbon filtration can work, as long as you do your homework and find a filter that has been tested and proven effective.
  • A treatment method that removes viruses will also work for bacteria and parasites.
  • In a pinch, you can boil your water for one minute to kill any microorganisms.

Even though most of us will never have to deal with viruses in our water, it's good to know that there are simple solutions.

If you have any questions or insights, please let us hear them in the comments below!

Sources

Here are some of the sources I used in researching for this article. 

Modes of Transmission of Infectious Diseases (10th International Congress on Clinical Virology & Infectious Diseases)

Drinking Water Chlorination: Frequently Asked Questions (Minnesota Department of Health)

Medical Definition of Virus (MedicineNet)

Bacteria & Virus Issues (Water Quality Association)

Understanding EN 14126:2003 for Battle Against COVID-19 (Health & Safety International)

A Guide to Drinking Water Treatment Technologies for Household Use (Centers for Disease Control and Prevention)

Last Updated on March 18, 2020

Marge Sweigart

I'm a healthy living blogger who loves to help people who care about having a healthy home environment make smart choices and save money. Read more

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