Does Reverse Osmosis Remove 1,4-Dioxane? A Homeowners’ Guide

Does Reverse Osmosis Remove 1,4-Dioxane? A Homeowners' Guide

1,4-Dioxane is a contaminant that is often found in drinking water. If you are a homeowner who has this compound in your drinking water, you may be wondering if reverse osmosis is effective for treating 1,4-dioxane.

Recent research has shown that reverse osmosis can reduce the concentration of 1,4-dioxane in drinking water by 68 to 96%. While this is impressive, many states have established a drinking water standard of 3 parts per billion for 1,4-dioxane. Depending on the concentration in your water, a 68% reduction may not be adequate to protect your family. There are other treatment methods that work very well for 1,4-dioxane such as specialty resins and advanced oxidation processes.

In this blog post, we will explore the question of whether reverse osmosis can effectively remove 1,4-dioxane from drinking water, how RO can be used to purify your water, and a host of other issues. Continue reading to learn more about 1,4-dioxane in drinking water.

Overview of 1,4-Dioxane1,4-dioxane molecule

1,4-dioxane, also known as 1,4-D, is an “emerging contaminant” – meaning it is currently not regulated by the EPA as scientists study it to gather more definitive evidence about its effects on human health and the environment.

What is 1,4-dioxane

1,4-dioxane is a clear liquid used as a solvent in the manufacture of chemicals. It was historically used as a stabilizer in chlorinated solvents, especially TCA. It can be found in paint, adhesives, pesticides and some consumer products such as household cleaners, detergents, shampoos, deodorants and cosmetics. The main industrial use for 1,4-dioxane is in degreasing solvents where it is present in combination with other chemicals.

Health concerns over 1,4-dioxane

Some health concerns over 1,4-dioxane in drinking water include its potential to cause liver and nasal cancers, as well as adverse effects on the liver and kidney. These health effects generally occur in people who are exposed to elevated levels of 1,4-dioxane over long periods of time.

While there is still some uncertainty around the long-term risks of exposure, it is important to properly treat water that contains 1,4-dioxane. The US Environmental Protection Agency recently established a 1-day health advisory of 4.0 part per million (ppm) and a 10-day health advisory of 0.4 ppm in drinking water.

How Does 1,4-Dioxane Get into My Drinking Water

1,4-D is a chemical compound that can contaminate drinking water supplies. It is known to enter the water from a variety of sources, including industrial use, accidental spills, and landfill leachate.

It can also be released into the environment as a result of treated wastewater discharge. 1,4-dioxane is a by-product of the manufacturing process of certain consumer products, and it can also leach from septic systems into groundwater.

1,4-D is a by-product found in many products, including paint strippers, dyes, greases, antifreeze and aircraft deicing fluids. It is also found in consumer products such as deodorants, shampoos and cosmetics.

It can contaminate ground or surface water utilized as drinking water after being discharged into the environment.

Using Reverse Osmosis to Remove 1,4-Dioxane from Waterreverse osmosis under sink filter

Reverse osmosis is known to remove many contaminants such as lead, fluoride, and PFAS from water. However, its effectiveness for treating 1,4-dioxane is not as well understood – this is partly because this is an emerging contaminant, and we are just beginning to study its presence in our drinking water.

Read my definitive guide on Whole House RO filters.

What is reverse osmosis

Reverse osmosis (RO) is a treatment technology that can be used to remove a wide variety of contaminants from water. RO works by passing water through a semipermeable membrane at an elevated pressure. The membrane has tiny pores that allow water molecules to pass through while it blocks the passage of larger contaminants.

The treated water is then collected on the other side of the membrane, while the contaminated water, known as brine, is flushed down the drain.

Many RO systems include pre-treatment to enhance the performance of the filter. This includes particle filters to prevent fouling of the membrane and activated carbon to remove chlorine which cand degrade the membrane.

Does reverse osmosis remove 1,4-dioxane

Several studies have been conducted to test the ability of RO systems to remove 1,4-dioxane. A report by New Jersey Drinking Water Quality Institute indicated that reverse osmosis reduces the concentration of 1,4-D between 68% and 96%. Another study found that RO filters remove 95% of 1,4-dioxane.

A recent study tested the ability of two different types of RO membranes to remove dioxane from water and found spiral wound type membranes performed the best.

These results indicate that RO can reduce the concentration of 1,4-dioxane significantly. However, the reductions offered by reverse osmosis may not be enough to reduce the levels to drinking water standards.

A key consideration is the concentration of 1,4-D present in your water. If the level is low (a few parts per billion), then RO would probably be adequate. However, if the concentrations are high (> 100 ppb), then you may need to use another treatment method.

Combining RO with Other Treatment Methods to Remove 1,4-D

If you have high levels of 1,4-D in your drinking water, or you just want to be certain your treatment process can remove all of it, you may have to combine reverse osmosis with a second treatment technology. Using an RO system in conjunction with other filtration processes yields a more effective result than using RO treatment alone.

Activated carbon is only partially effective at treating 1,4-dioxane by itself. The NJ study mentioned above indicated that using carbon to polish water treated with reverse osmosis provided an additional 56% reduction in the contaminant concentration.

Test Your Drinking Water for 1,4-Dioxane

1,4-Dioxane Water Test Kit
Tap Score has an easy-to-use test kit to measure1,4-dioxane in your drinking water.

Tap Score’s Home Test Kit for 1,4-Dioxane in Drinking Water is an easy and reliable way to test your water for the presence of 1,4-dioxane. This test package provides all of the materials necessary to collect and submit a sample for certified laboratory testing.

The results will include a detailed analysis of 1,4-dioxane by EPA method 8260B (or equivalent). Knowing what’s in your water is the first step to keeping your family safe.

Order your Tap Score 1,4-Dioxane test kit today.

What Treatment Methods Remove 1,4-Dioxane

Fortunately, there are other treatment methods besides reverse osmosis that can treat water contaminated with 1,4-dioxane. The following technologies are known to work extremely well for removing 1,4-D.

Specialty resin

Specialty resins are a type of synthetic media that is engineered to remove 1,4-dioxane from water. A very effective synthetic media system is Ambersorb 560 manufactured by the Dow Chemical Company.

Ambersorb 560 is a carbon-based resin that differs from activated carbon because it has a greater sorptive capacity for hydrophobic organic compounds such as 1,4-dioxane. This treatment method involves placing placed the media in pressure vessels and pumping the contaminated water through it.

Advanced oxidation processes

Highly reactive hydroxyl radicals (·OH) are used in oxidizing pollutants in advanced oxidation processes (AOPs). AOP is a commercially available treatment choice for addressing 1,4-dioxane in drinking water. The very reactive hydroxyl radicals break down 1,4-D to carbon dioxide, water, and residual chloride.


Do refrigerator filters remove 1,4-dioxane?

Refrigerator filters do not remove 1,4-dioxane from drinking water. These filters include particle filters and activated carbon – neither of these remove 1,4-D.

Do Brita filters remove dioxane?

No, Brita filters do not remove dioxane from water. These filters use activated carbon, but carbon is not effective at treating this contaminant.

Does activated carbon remove 1,4-dioxane?

Activated carbon, also known as charcoal, is not effective at treating this contaminant. Studies indicate that carbon can reduce the concentration of 1,4-D by 10 to 20%.

Do water softeners remove 1,4-dioxane?

Water softeners do not remove 1,4-dioxane from water. These systems only remove hardness minerals such as calcium and magnesium.


Reverse osmosis is an effective treatment method for removing many contaminants from drinking water, but it may not be enough to remove all traces of 1,4-dioxane. RO combined with activated carbon can remove almost all of the 1,4-D in your water. However, there will still be trace amounts of it, even after being treated with two methods.

If you are concerned about this contaminant in your water and want to remove all of it, you should consider using a specialty resin such as Dow’s Ambersorb 560. This specialty resin is the most effective treatment method available for removing 1,4-dioxane.

Boch Richard

Richard Boch is a chemical engineer responsible for designing water filtration systems for industrial and residential customers. He has more than 20 years of experience with ion exchange, activated carbon, and reverse osmosis. Richard's expertise has made him a go-to source for municipalities and businesses looking to improve their water quality. When he's not working, Richard enjoys spending time with his wife and two young children. You can also follow him on LinkedIn, Twitter and Facebook.

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