Does Reverse Osmosis Remove Hexavalent Chromium from Water?

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Chromium 6, also known as hexavalent chromium, might sound familiar. Its adverse health effects were the subject of the film Erin Brockovich. Based on a true story, Erin Brockovich takes on a giant power company found to be polluting a town’s water supply with chromium 6, leading to a large settlement from the company to those affected by exposure to the chemical.

You would think the case would mean that water tainted with chromium 6 is a thing of the past. But unfortunately, that is not the case, and it remains in most water supplies to this day.

If you are considering getting a reverse osmosis system to avoid ingesting this chemical, then you may want to know how effective it is at removing it. Let’s see.

Key Takeaways

  • Reverse osmosis does remove hexavalent chromium, or chromium 6, from water, and it does so with a high level of efficacy (more than 97% is highly realistic).

Does Reverse Osmosis Remove Hexavalent Chromium from Water?

Does reverse osmosis remove hexavalent chromium from water?

Yes, reverse osmosis is a very effective method of filtration for chromium 6 or hexavalent chromium. The tiny pores of the reverse osmosis membrane are too small for the hexavalent chromium to pass through, and it is eliminated with the wastewater.

When looking to purchase a reverse osmosis system, look for NSF certifications 53 and 58.It could mean that a certain product has been independently tested for its chromium 6 reduction capabilities. But you need to make sure that testing has been conducted for chromium 6 reduction specifically – you can do so by checking the lab data (test results) usually published in the product manual.

blue reverse osmosis membrane

How Well Does Reverse Osmosis Remove Chromium 6?

Very effectively! Different brands will have different mileage, but the AquaTru countertop model removes 97.2% of chromium 6, for example. Some models will remove even more than that.

What Is Hexavalent Chromium and How Does It Enter Our Water Supply?

Hexavalent chromium is also known as chromium 6, chromium(VI), or Cr(VI) and represents the element chromium in its 6th oxidation state.

Unfortunately, it is often found in water supplies due to its prevalent use in industrial manufacturing of dyes, paint, and ink, and runoff from these processes getting into groundwater supplies.

Health Effects

A lot of dissolved solids found in water are nothing to be too worried about in small doses, but unfortunately, this is not one of them. Studies have shown that chromium 6 can increase the risk of gastric tumors and cancers, with long-term exposure also linked to liver and reproductive damage.

In industrial workers exposed to it, hexavalent chromium has been associated with:

  • Lung cancer due to airborne chromium
  • Irritation or damage to the nose, throat, and lungs due to airborne hexavalent chromium
  • Irritation or damage to the eyes and skin upon direct contact with hexavalent chromium

Federal Drinking Water Standards for Chromium 6

The EPA has not set a federal limit for chromium 6 in drinking water. There is a standard for total chromium, which is chromium 3 and 6, though ingesting chromium 3 does not pose health risks. The EPA limit for total chromium is 100 ppb (parts per billion).

However, California has set a goal of limiting chromium 6 in drinking water to 0.02 ppb, but it is a goal, not a hard limit.

How to Test If Chromium 6 Is in Your Drinking Water

Considering its widespread presence and severe health consequences, testing your home water for chromium 6 makes sense. Professional lab testing can detect this and hundreds of other contaminants in your drinking water, such as pesticides and heavy metals.

You can also check the latest water quality report for your area, which should be provided to you by your water utility company for free. This will not be effective if you have a private well, though.

What you can also do is check your water utility on the EWG Tap Water Database, and utilize their interactive map showing the average chromium 6 concentration in different water supplies.

Water Testing Report

Other Ways to Remove Chromium 6 from Water

Reverse osmosis is one of the most effective ways to filter chromium 6, but another method you can use is ion exchange. Activated carbon filters, Brita water filters, etc., will not be effective at removing enough of it to get it down to 0.02 ppb.

Ion Exchange

A highly effective way to remove chromium-6 from water is with an ion exchange water treatment unit. This involves sending your home’s water through a small tank containing tiny beads. This resin causes chromium 6 to attach to it, removing it from the water. Ion exchange filters can also often remove arsenic and manganese.


Water distillers are also an excellent way to remove many contaminants, hexavalent chromium included, from your water. The downside is that it is time consuming and often costly to run.

The unpurified water is added to a boiling chamber and heated until it evaporates. The water vapor collects in a cooling coil, where it is cooled back to a liquid.

This process removes almost all contaminants from water.

What About Chromium 3?

There has been a lot of debate going on about the dangers of chromium 6 in drinking water and how/whether or not to remove it using appropriate filtration methods.

But what about chromium 3, which is another form of chromium found in water supplies? Should you be worried about that, too?

Good news is, chromium 3 aka trivalent chromium has low toxicity. As such, it is considered to not be very harmful to human health. That’s because chromium 3 does not get absorbed through the gastrointestinal tract easily. It has been shown that when ingesting supplements containing chromium 3, it is still not associated with adverse health issues.

Bottom line: You shouldn’t be worried about chromium 3 too much and instead focus all your energy on removing chromium 6 from your water supply entirely.

If you have any thoughts about the question, does reverse osmosis remove chromium 6, please don’t hesitate to leave a comment below!

About the Author Gene Fitzgerald

Gene Fitzgerald is one of the founders of BOS and currently head of content creation. She has 8+ years of experience as a water treatment specialist under her belt making her our senior scientist. Outside of BOS, Gene loves reading books on philosophy & social issues, making music, and hiking.
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