Does Reverse Osmosis Remove Bacteria?

Does Reverse Osmosis Remove Bacteria?

Depending on where you live, it is very possible that your water contains bacteria that could be potentially harmful to you and your family. Reverse osmosis stands the test of time as the one of the most holistic and reliable filtration methods available to humans, removing up to 99% of harmful contaminants in water. 

So does reverse osmosis remove bacteria too? The simple answer is - YES. 

How Does Reverse Osmosis Remove Bacteria?

Reverse Osmosis (RO) systems use semipermeable membranes that contain very tiny holes (0.0001 micron). These holes are designed to only allow water molecules to run through them, leaving all of the nasty contaminants you don't want in your water behind. 

Common Bacteria in Water Removed with RO:

• Salmonella
• Coliform
• Legionella
• E. Coli
• Cryptosporidium
• Adenovirus
• Giardia
• Hepatitis A
• Heterotrophic Bacteria

Is There Anything that RO Systems Can't Remove?

While reverse osmosis is an effective filtration method, contaminants like dissolved gases (ie. hydrogen sulfide or rotten egg smell) cannot be removed. To combat this, many RO systems include pre and post filters which help to remove this element from your water source. 

Additionally, there are certain pesticides and volatile organic chemicals (VOCs) that are not removed by RO. If you are worried about a specific contaminant and the efficacy of reverse osmosis, it is best to consult with a professional prior to installation.

Health Risks Associated with Bacteria Contaminated Water

Risks associated with bacteria consumption through water very from mild illness to severe illness and death. Common illnesses include diarrhea, giardiasis, dysentery, typhoid fever, E. Coli infection, and salmonellois. Regular and ongoing exposure to bacteria can result in long-term health issues. 

Common Sources of Bacterial Contamination in Water:

• Municipal sewage
• Septic systems
• Animal waste
• Agriculture pollution
• Storm water runoff

Additional Considerations for Using RO Systems to Remove Bacteria

Maintenance: It is critical that you follow your system's guidelines for membrane and filter replacement. Expired membranes lose their effectiveness as their micron rating decreases. This can result in bacteria slipping through the membrane and entering your water supply.

Signs of System Inefficiency or Failure: If you notice that your system is not performing as it has in the past, this can be a cause for concern. Most RO systems are built with a lifespan of 10-20 years depending on the manufacturer. Common signs that your system is in need of maintenance include, cloudy or murky water, smelly water, or a drop in water pressure. 

Practical Tips for Using RO Systems: 

• Replace pre and post filters every 6-12 months
• Replace membranes every 2-3 years
• Rinse system with disinfectant annually 

Other Methods for Removing Bacteria From Water

While reverse osmosis is one of the most effective ways to remove bacteria from water, there are other options available to homeowners as well. We've included a number of alternative filtration options if you've decided against going with an RO system below.

Additional Options:

• UV Treatment
• Distillation
• Dosing Systems
• Boiling Water

Helpful Reputable Resources

Water Related Illnesses - National Institutes of Health

Home Water Treatment - Centers for Disease Control

Drinking Water Treatment - University of Nebraska-Lincoln

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