How to Remove E. coli from Water

🀝 Our content is written by humans, not AI robots. Learn More

E. coli might sound like an unlikely pathogen to contaminate water in the United States, but the reality is that hundreds of thousands of people are infected with this bacteria every year – so it’s more of a prevalent problem than many of us realize.

In this guide, we’ve shared everything you should know about the 7 most effective treatment methods to remove or kill E. coli bacteria in water.

πŸ“Œ Key Takeaways:

  • E. coli is a type of coliform bacteria that contaminates foods and may be found in untreated drinking water supplies.
  • Some of the possible health effects of exposure to E. coli bacteria in water include diarrhea, nausea, vomiting, and fever.
  • You can kill or remove E. coli from your water with UV systems, chemical injection systems, ceramic filters, water distillers, reverse osmosis systems, and submicron filters.

πŸ’‘ What Is E. Coli?

E. coli is a bacteria that’s found in the intestines of warm-blooded animals and humans. Its full name is Escherichia coli.

Most strains of E. coli are harmless and even beneficial. However, some can cause illness, and can even be life-threatening to some people.

It’s estimated that in the US alone, E. coli infections cause some 265,000 illnesses and about 100 deaths every year.

Shiga toxin-producing E. coli is a common strain of E. coli that has harmful health effects. We’re usually exposed to this E. coli bacteria due to consuming contaminated foods, but it may also be present in untreated water supplies.

E.coli detected in tap water

❓ Is E. Coli in Water Harmful?

E. coli is possibly harmful in water. The health concern posed by E. coli in your water depends on the strain of E. coli present.

As we mentioned above, Shiga toxin-producing E. coli is one of the most dangerous strains of E. coli in terms of its health effects.

In a usual scenario, E. coli symptoms persist for up to 10 days. Most healthy people will recover completely from an E. coli infection without the need for medical attention. However, infants and babies, the elderly, and immunocompromised people may experience life-threatening complications as a result of the infection.

πŸ€” How Does E. Coli Get Into Drinking Water?

Usually, E. coli from animal waste would be broken down during natural decomposition processes. However, there are some occasions when this bacteria may end up in groundwater or surface water, increasing our risk of exposure.

There are a few ways that E. coli get into drinking water, including:

  • Leaking septic systems: Poorly maintained septic systems may leak waste into the surrounding soils, causing cause E. coli and other bacteria to leak into local groundwater. This could lead to the contamination of wells and other drinking water sources.
  • Stormwater runoff & flooding: Storms may lead to heavy rain and flooding, which could carry bacteria like E.coli into surface water bodies and groundwater supplies.
  • Animal waste: Wildlife or grazing livestock near a water source could contaminate the water with fecal matter. If this contains E. coli, it’ll introduce this bacteria strain to the water.
  • Agricultural runoff: Runoff from agricultural sites could cause manure or animal waste to be carried into nearby water sources. This is especially likely during irrigation and periods of heavy rainfall.

You’re more at risk of E. coli contamination if you have a private well water system than if you get your drinking water from a municipal supplier.

While public water systems test and disinfect water for drinking, private wells are unregulated, and most well owners only test their water once a year.

That means you could end up drinking E. coli-contaminated well water without knowing.

Damaged septic tank

πŸ“‘ Possible Health Effects of E. Coli

There are a few likely health risks associated with E. coli, depending on the type of bacteria present in your water.

If your water is contaminated with dangerous bacteria, you may experience the symptoms of an E. coli infection.

Some of the side effects of an infection caused by this bacteria include:

  • Diarrhea
  • Abdominal cramps
  • Fever
  • Vomiting

You may experience more serious side effects, including hemolytic uremic syndrome (HUS), a potentially life-threatening complication of E. coli that affects the kidneys and the red blood cells. You’re advised to see a medical professional urgently if you have severe bloody diarrhea or are experiencing symptoms of dehydration.

βœ… How to Remove E. Coli from Tap Water

Here are the best water treatment methods to kill or remove E. coli bacteria from your drinking water.

UV Water Purification

UV water purification is one of the most effective methods of E. coli and bacteria killing.

UV rays are used to treat water that flows through the UV system. The ultraviolet light damages the DNA of harmful pathogens like E. coli, killing them and preventing them from making you sick.

When the right UV dose is used, UV systems can kill up to 99.99% of E. coli in a drinking water supply.

The effectiveness of a UV system is dependent on the initial water clarity. If your water is turbid with sediment or other particulates, you’ll need to install a pre-treatment system to remove these contaminants. This will allow a UV system to kill all the E. coli in your water supply.

Most UV purifiers are installed at the main water line into your home, upstream of your hot water heater. That means your entire plumbing system and all fixtures and appliances are protected against bacterial contamination.

Uv water purification system installed in basement

Chlorine Treatment Systems

Chlorine treatment systems are another effective method of killing E. coli and other harmful bacteria.

These systems provide a small-scale version of the disinfection process that’s used by municipal water suppliers. They inject chlorine into water, then hold the water in a tank to allow the chlorine to take effect.

Chlorine breaks the bonds that hold bacteria, viruses, and other pathogens together, leaving them present in the water supply but unable to cause harm.

Many systems have an activated carbon post-filter that removes chlorine once it has done its job in killing E. coli and other pathogens, improving the taste and quality of the water.

A chlorine injection system uses a special dosing pump that only injects a safe amount of chlorine into water. However, this water treatment method is riskier than using a natural method like UV purification, and you may prefer not to add chemicals to your drinking water lines.

Submicron Filters

Submicron filters have tiny filter pores that are small enough to trap contaminants like coliform bacteria and E. coli.

Most water filters have a pore size of around 1-5 microns. When water is treated in these filters, the microorganisms (including any E. coli) are small enough to slip straight through the filter pores.

Submicron filters have a pore size of 0.22 microns or less, so they’re capable of trapping up to 99.99% of waterborne contaminants like E. coli.

Most submicron water filters are found in emergency or portable water filters that you can use to treat natural untreated water sources while hiking, traveling, or camping off-grid.

There are a couple of brands that sell submicron filters in countertop systems and water filter pitchers for well water treatment.

Submicron filter on table

Ceramic Filters

A ceramic water filter is one of the early developed water filters that’s still widely used today for removing a variety of drinking water contaminants.

Ceramic filters are made from a porous ceramic material, often in the form of a candle-shaped cartridge or a disc. They use mechanical filtration that physically blocks contaminants larger than the filter pore size, preventing them from passing through with water molecules.

Ceramic water filters have a very varied pore size – typically from 0.3 to 50 microns. Filters with a smaller pore size can reduce bacteria like E. coli by creating a microbial barrier that prevents these contaminants from traveling beyond the filter media.

On average, a ceramic water filter can remove 87-99% of E. coli contamination from tap water.

Note that ceramic filters can’t usually remove viruses because these are much smaller than bacteria.

Water Distillers

Water distillers use the process of evaporation and condensation to remove up to 99.5% of all impurities (including fecal coliform and E. coli) from a contaminated water source.

These water treatment units boil water until it evaporates into steam, then cool the steam back into liquid water, leaving behind most of the impurities in the process.

The purified water is collected in a separate container, and the impurities that are unable to vaporize with water remain in the boiling chamber.

We couldn’t find any exact removal percentages for E. coli, but multiple sources say that water distillation is a highly effective method of killing coliform bacteria.

The only real setback of water distillation is that the process takes hours, so it’s not a quick way to access safe drinking water.

Countertop water distiller

Reverse Osmosis Systems

Reverse osmosis is a multi-stage water filtration process that, like, water distillation, removes up to 99% of all dissolved solids in tap water.

The RO process sends water through several filtration stages, including sediment and carbon filters, as well as a semi-permeable membrane.

This membrane has tiny pores as small as 0.0001 microns, which are capable of removing contaminants down to bacteria-sized pathogens.

On average, a reverse osmosis system can remove up to 99.9% of E. coli from drinking water, depending on the quality of the filters and the membrane pore size.

You can install an RO system underneath your kitchen sink or on your kitchen countertop to remove E. coli from your faucet water.


Finally, if you don’t want to invest in a water treatment system and you just need to protect your family from E. coli and other bacteria in the short term, we recommend boiling your water.

Boiling water kills or inactivates E. coli, making water safe to drink (once it has cooled). Just make sure to heat water to at least 149ΒΊF (if you can see and hear the water bubbling, it should have surpassed this temperature), and leave it on a rolling boil for at least one minute to ensure all bacteria are killed.

We don’t suggest boiling your water as a long-term solution if you have a permanent issue with E. coli in your water supply. The process is time-consuming and requires that you manually boil any water that you plan to use for cooking or drinking purposes.

Boiling water to remove e.coli

πŸ’― What’s The Best Way To Remove E. Coli From Water?

In our opinion, the best way to remove E. coli from tap water is with a UV purifier.

The reason why we think UV systems are ideal for this purpose is that they use an all natural water treatment process and are very easy to maintain (you just replace the UV lamp once a year).

Plus, they’re effective in killing other microorganisms, like bacteria and other viruses, and they’re installed as whole-home systems, so they protect your entire water system from bacteria.

πŸ”Ž How To Know If A Water Filter System Can Remove E. Coli

The best way to know whether or not a water filter system can remove E. coli is to check the product description and look for contaminant removal data.

Many manufacturers of water treatment systems share test results that display the contaminants that the system has been tested to remove. You can check for E. coli on the list, and see how much of this contaminant the system can remove.

If you can’t find test data online, contact the manufacturer and ask if they can email you a copy of their testing.

πŸ“‘ Final Word

E. coli has the potential to cause serious sickness and even death. It’s important to protect yourself and your family from this pathogen, especially if you have a private well that isn’t regulated by the EPA.

Our advice is to get your water tested to confirm whether or not E. coli is present. In the meantime, drink bottled water or boil your water to make it safe to drink.


Can E. coli be removed from water?

Yes, E. coli can be removed from water. A few ways to effectively remove E. coli are by boiling water, using a water distiller, a reverse osmosis system, a nanofilter, or treating water with a UV purifier or a chlorine disinfection system.

What water filter kills E. coli?

No type of water filter can kill E. coli. It’s in the name – water filters filter out contaminants, but they can’t kill them. If you’re specifically looking to kill E. coli rather than removing it, look at UV water purifiers and chemical injection systems.

How much E. coli is removed by filtration?

The amount of E. coli that’s removed by filtration depends on the type of water filter being used. A generic filter like an activated carbon filter won’t remove any E. coli because the bacteria are small enough to pass through the fitter’s pores. However, submicron filters and reverse osmosis membranes can remove up to 99.99% of E. coli. Check a specific filter’s test results for accurate information.

  • Jennifer Byrd
    Water Treatment Specialist

    For 20+ years, Jennifer has championed clean water. From navigating operations to leading sales, she's tackled diverse industry challenges. Now, at Redbird Water, she crafts personalized solutions for homes, businesses, and factories. A past Chamber President and industry advocate, Jennifer leverages her expertise in cutting-edge filtration and custom design to transform water concerns into crystal-clear solutions.

Leave a Comment

Your email address will not be published. Required fields are marked *

Scroll to Top