Does Reverse Osmosis Remove Bacteria? Here’s What We Learned

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Reverse Osmosis is a popular water filtration system used in homes and businesses around the world. However, does reverse osmosis remove harmful bacteria?

Yes, reverse osmosis removes 99% of all contaminants including bacteria, viruses, heavy metals, pesticides, herbicides, pharmaceuticals, and even chlorine. In fact, most municipal drinking water systems use reverse osmosis as part of their treatment process.

I’ll explain why reverse osmosis is such a powerful tool for removing bacteria and why it’s worth considering adding one to your home.

does reverse osmosis remove bacteria

Can Bacteria Grow in Reverse Osmosis Water?

Reverse osmosis water is great for drinking because it eliminates almost all impurities and toxins from your tap water. But it does leave behind some minerals and nutrients that can support bacterial growth. That said, it’s extremely unlikely that bacteria would ever grow in your drinking water.

Bacterial growth is dependent upon the presence of certain nutrients found in foods or liquids. These nutrients include sugars, proteins, fats, vitamins, and minerals. Since reverse osmosis membranes filter out all of these nutrients, it makes sense that bacteria wouldn’t grow in your drinking water after passing through a reverse osmosis membrane.

However, there are two exceptions to this rule. First, if your RO membrane isn’t properly maintained, it might allow some harmful elements to pass through. Second, if your RO membrane is damaged, it might let some dangerous chemicals enter your drinking water.

In either case, it’s important to keep your RO system clean and well-maintained. Otherwise, you risk allowing harmful elements to enter your drinking water.

Does Reverse Osmosis Remove Bacteria?

Reverse osmosis removes bacteria from your tap water. A reverse osmosis filter works by passing water through a semi-permeable membrane. Water passes through the pores of the membrane, leaving behind any contaminants or minerals. Since the pore size of a reverse osmosis membrane is five times smaller than a human hair, it’s impossible for anything larger than a single molecule to pass through.

Bacteria and viruses are five thousand times bigger than a single molecule, so only water molecules, and some mineral ions can flow through the reverse osmosis membrane. Other impurities and heavy metals remain in the treated water.

Let’s take a look at some of the most common types of microorganisms found in tap water and whether a reverse-osmosis (RO) system can remove them from the water.

Do RO Filters Remove Legionella Bacteria?

Legionella bacteria are tiny organisms that live in our bodies. They cause pneumonia and other respiratory infections. Some types of Legionella bacteria can grow to more than 50 micrometers in length.

A reverse osmosis water filter removes particles down to 1 nanometer in diameter. Therefore, if your water source has Legionella bacteria, your RO water filter should be able to remove them.

This means that if you live in an area where Legionella is common, you should consider getting a water purification system that uses RO filters.

Does Reverse Osmosis Filter out Bacteria Like Vibrios?

You may not realize it, but there are plenty of bacteria floating around in our drinking water. Some of those bacteria can cause serious health problems if consumed. Fortunately, reverse osmosis systems can remove most of them.

Vibrio Cholerae is a bacterium that causes cholera. It can be transmitted through water and food. The body size of vibrios is between 0.5 and 0.8 microns, which is much larger than the filtrations accuracy of a reverse osmosis system. Therefore, it can be filtered out by the reverse osmotic system.

Is the Reverse Osmosis System Effective at Removing Bacteria Like Salmonella?

Salmonella is a very common pathogenic bacterium in nature and prefers to reside in human bodies and animal bodies. It can cause serious illness in people with weak immune systems.

Salmonella causes gastrointestinal illness, including diarrhea, abdominal cramps, nausea, fever, and sometimes bloody stools. It is highly resistant to most common drugs used to treat bacterial infections. It can live in water for up to three weeks, so it’s hard to clean up after an outbreak.

With the reverse o­smosis system’s filtration precision of only one-thousandth of a millimeter, Salmonella can certainly filter out.

Does Reverse Osmosis Remove E. Coli?

One of the most common types of bacterium is known as Escherichia coli (E.coli). E. coli live in the intestines of mammals and birds. They cause mild stomach upsets in people who eat them. However, they can also cause severe food poisoning if eaten in large quantities.

After the raw water passes through an activated carbon filter and is pressurized by the pumps, it goes through the reverse osmosis membrane. The pores of the membrane are only 1/10,000th of the size of E. Coli, so there is no way for E. coli to pass through the membrane. As a result, the reverse osmotic filtration process removes E. coli from the water.

Does Reverse Osmosis Filter Remove Rotavirus?

Rotavirus is a virus that causes gastroenteritis. It is most commonly found in children under 5 years old. Symptoms include diarrhea, vomiting, stomach cramps, fever, headache, muscle aches, loss of appetite, and fatigue.

Since the size of the rotavirus is far bigger than a reverse osmosis filter’s pore size, it won’t pass through the membrane. Therefore, it will not be filtered out. You should consult your doctor if you think you may have contracted rotavirus.

Does RO Filter Remove Coronavirus?

The coronavirus is about 100 nanometers wide, and the pores of the reverse osmotic membrane are only 1 nanometer wide. So if your reverse osmosis system has a filter with a pore size of 1 nanometer, it should be able to remove the coronavirus.

How Effective is RO Against Bacteria?

After installing your RO system correctly, it should be able to remove 99.9% of impurities from water.

A reverse osmosis system removes almost all the contaminants from your water. However, there are certain factors that can reduce its ability to remove bacteria.

Membrane fouling and degradation are two of those factors. Membranes become clogged with organic matter, causing them to lose their efficiency. And if the membranes degrade, they won’t work as well.

So it’s important to regularly clean your filters and change your RO membranes. You can find replacement RO membranes online or at local hardware stores.

How Much Bacteria Does RO Remove?

Reverse osmosis actually removes almost anything that isn’t dissolved in water. Organic matter is called “contaminants,” and a good reverse osmosis filter is capable of removing 99.9% of those contaminants.

Common examples of the types of contaminants that reverse osmosis filters can remove include Campylobacter, shigella, e.coli, salmonella, hepatitis a, rotavirus, norovirus, and others.

How Does Reverse Osmosis Remove Bacteria From Drinking Water?

Reverse osmosis removes bacteria from drinking water using pressure. The contaminants are moved from high concentrations to low concentrations. Then the purified water is passed through a series of filters before being released into your tap.

A reverse osmosis system consists of five stages: pre-filter, carbon filter, RO membrane, post-filter, and deionization. Each stage works to remove impurities from the water.

Pre-Filter: The pre-filter is used to remove large particles from the incoming water. These include sand, dirt, rust, and debris.

Carbon Filter: The carbon filter helps reduce chlorine taste and odor. Chlorine is added to municipal water supplies to kill harmful bacteria. However, chlorinated water still tastes bad. Carbon filters remove chlorine taste and odor.

RO Membrane: The RO membrane is where the actual filtering takes place. The membrane is made out of polyamide material. Polyamides are strong, durable materials that allow only pure water to pass through.

Post-Filter: The post-filter is used to further remove residual chemicals and minerals from the water.

Deionization: Deionization is used to remove ions from the water. Ions are charged molecules that cause problems if they remain in the water after treatment. Deionization removes these ions from the water.

Once the water leaves the last stage, it is safe to drink. You may notice a slight change in color, smell, or taste. But don’t worry, the water is perfectly safe to drink.


Does a Bacteria-removing Reverse Osmosis System Expensive?

Not really. Many home RO water filters are quite affordable. There are always going to be high-priced models available, but RO is not something that’s out of reach for most people.

Does RO Remove Bacterial Contaminants from Drinking Water?

Most RO (reverse osmosis) units are specifically made for treating tap/drinking water. This means that you know that your purified drinking waters are safe to drink.

How Can We Remove Bacteria from Our Drinking Water Without Using Reverse Osmosis (RO)?

There are several different ways to purify your water, but RO filters are usually considered to be the most efficient method for doing so. However, if you’re looking for an alternative to RO filtration, you might want to look into purchasing a UV filter instead.

Does a Tankless RO Have Less Bacterial Contamination Than a Tank-based RO?

The filtering processes of both tank and tankless systems are similar. However, tank systems can lead to bacterial growth in the tank itself, so as water passes through the tanks, they may be contaminated.

Bottom Line

In conclusion, reverse osmosis removes bacteria. It is a process where water passes through a membrane filter and is purified by passing through a series of filters.

This purification process eliminates impurities such as chlorine, heavy metals, and organic compounds. Reverse osmosis is effective because it uses pressure to force water through the membranes.

In addition, it is safe because it does not expose users to harmful chemicals.

Joanna G. Lackey

Hi, I'm Joanna, a writer freelance writer who specializes in topics about health and nutrition. I live in the Pacific Northwest with my husband and three children. I'm a mom to two dogs and a cat. I love reading, writing, and taking photos.