Article Last Updated: July 2023
Does Reverse Osmosis Remove Arsenic?
Yes, reverse osmosis removes arsenic from water.
Reverse osmosis is capable of removing arsenic with an efficiency of 80 to 99%. Pre-treatment may be required depending on the water quality and the performance of the RO unit will vary depending on its specific features.
What is Arsenic?
Arsenic is a natural element of the earth’s crust and can be found in all areas of the environment including air, land and water.
People who use well water or live close to areas of industrial and agricultural pollution are also at a higher risk of arsenic exposure.
It is estimated that 2.1 million people in the US are exposed to arsenic in their drinking water according to the USGS (United States Geological Survey). Especially people who get their water supplied from a domestic well.
According to the WHO, 140 million people worldwide are exposed to arsenic in their drinking water and have unknowingly consumed it a rate of 10ppm which is higher than the maximum safety consumption rate.
Exposure to arsenic can cause problems for your skin, kidney, liver and reduce the amount of red and white blood cells in your body. This results in fatigue and a higher risk of getting infections.
Also, a prolonged exposure to arsenic can be fatal.
This article will outline how reverse osmosis (RO for short) can help effectively treat and remove any arsenic present in your drinking water.
How Does Arsenic Get Into Your Drinking Water?
1. Natural means. Naturally through mineral deposits, for example rocks that contain arsenic can dissolve and enter into oceans, rivers, lakes and well water.
2. Human activities. The other way is through human activities such as industrial and agriculture waste.
Things like pesticides, animal feed, industrial waste, arsenic-containing fertilizers, mining and so on.
Arsenic has little to no taste, odor or smell!
This means you can’t easily detect it in drinking water. Use a water test kit, in order to know for sure if your water is contaminated with arsenic and to what degree.
It is possible to get a cheap water test kit online. However, a laboratory water test is the only way to get the most accurate results.
The Total Water Arsenic Test is an affordable way to get your water professionally tested.
Side Effects of Arsenic
- Discoloration and thickening of the skin.
- Stomach pain.
- Numbness in feet and hands.
- Partial paralysis.
In addition to all of these symptoms, long-term exposure to arsenic can create even more chronic conditions.
For instance, the WHO says that continuous and prolonged exposure to arsenic can lead to skin cancer and lesions.
How Does a Reverse Osmosis System Remove Arsenic?
Reverse osmosis works by forcing water through a membrane which means that nothing is left behind after the water passes through.
These membranes consist of thousands of tiny pores that measure around 0.0001 micron meanwhile arsenic typically measures around 0.1 micron. This means that arsenic and anything larger than 0.0001 micron will not pass through into your drinking water.
The tiny size of microns in comparison to the size of most contaminants is why reverse osmosis (RO) is a near-failsafe method of removing several hundred contaminants from water.
How Much Arsenic Does RO Remove?
The effectiveness of an RO system depends on a number of things like its design, number of filters etc. Lower estimates of arsenic removal is between 40% – 70%.
However, most modern RO units are capable of treating and removing arsenic at a rate of between 80% to 99% effectiveness. This is why RO is one of the best water filter arsenic removal methods.
Does Reverse Osmosis Remove Fluoride?
Similar to Arsenic, fluoride molecules are larger than the 0.0001 micron membrane size of RO filters.
RO’s tiny pores also means that it doesn’t just remove arsenic and fluoride from water but it also removes other contaminants like chromium, sodium, copper, chlorine, PFOA, PFAS and lead.
A basic RO unit is capable of removing at least 80% of fluoride from your drinking water. However, most modern RO units are able to remove up to 99.9% of fluoride especially if they have multiple states of filtration, which most do.
What Other Contaminants Do RO Filters Remove?
- Metal ions.
- Calcium and salts.
Reverse osmosis is so popular because it significantly improves the quality of your water supply and is capable of removing and treating up to 99.9% of almost all total dissolved solids (TDS).
What Does RO *Not* Treat?
There is very little that reverse osmosis doesn’t treat. The list below are things that it is capable of treating but at a lower level of effectiveness. The specific rate of effectiveness on a specific contaminant will be outlined by the manufacturer of your specific RO system.
- Dissolved gasses like radon, methane, carbon dioxide.
As the list above indicates, RO is by no means perfect and certainly has its limitations. However, this is why most modern RO systems have multiple stages of filtration with at least one or two other filter methods.
Issues With Under Sink RO Systems
1. It Can Make Your Drinking Water Bland and ‘Empty’.
Some people find that RO filtered water can have a bland or “empty” taste because all the minerals (e.g. calcium and magnesium) are removed along with the contaminants. However, most modern RO systems “remineralize”, that is to re-introduce healthy minerals back into the water after it’s been filtered.
2. RO Systems Create Wastewater (But You Won’t Notice).
An RO membrane is not like a typical filter.
This process creates a certain amount of wastewater. The good news is that almost all modern reverse osmosis systems are extremely efficient with this and in most cases you will hardly notice.
RO systems don’t come cheap and you can expect to pay several hundred dollars for a decent RO system. However, the good news is that there is a lot of choice on the market today. But if you find a suspiciously cheap unit (i.e. anything under $200) perhaps investigate the manufacturer before parting with your hard earned cash.
4. It Requires On-going Maintenance.
The typical reverse osmosis system lasts for over 10 years. However, you will still need to perform maintenance periodically to ensure the system is working at an optimal level.
- RO membranes typically need to be replaced every 2 years. Forgetting to do this could put you at the risk of contamination so it’s very important.
- Depending on the system, the filters may need changing and this is either 6-9 months for some systems and 12 months for others.
Whatever the case, the first port of call is to check the specific cleaning instructions and product manual. Each RO machine you purchase will come with its own specific maintenance regime.
However, almost all modern reverse osmosis devices are very easy to maintain especially when you compare it to other water filter methods.
Other Ways To Remove Arsenic
- Aside from RO filters, there are several countertop water filter systems that also treat arsenic, the best examples are Berkey and Aquatru.
- Water distillers remove everything from water including arsenic.
- Other notable water filter methods include ion exchange which offers high levels of arsenic treatment.
- Activated carbon can reduce arsenic by up to 70%.
- There are also dedicated whole house filters that specifically treat arsenic, this is ideal for extremely high rates of arsenic.
AquaTru Water Filter
Berkey Water Filter
|- Arsenic: Approx 90% (unspecified). |
- Fluoride by 91.8% (WITHOUT extra filters).
- Lead 97.5%
- Benzene 99.9%
- Chlorine 96.6%
- Cysts 99.99%
|- Arsenic by 99.9% (special filters required). |
- Fluoride by 99.9% (special filters required).
- Lead 97.5%
- Benzene 99.8%
|Available in 1-size only.||Available in various sizes.|
|Plastic materials.||Metal & plastic materials.|
|Number of filters: 3||Number of filters: 2 - 4|
|Filter methods: Mechanical, Reverse Osmosis & Activated Carbon filters.||Filter methods: Black microporous-filters & white fluoride Filters|
|4-stage filter process.||2-stage filter process.|
|Holds a maximum water capacity of 3-quarts.||2.25 Gallons|
|45.7 x 45.7 x 38.1 cm||19" High x 8.5" Diameter|
|System: 1 year limited warranty.||Filters: 2 years; System: 1 year.|
|Full Performance Data Sheet (AquaTru).||Berkey Contaminants List |
NSF/ANSI test results
|SPECIAL OFFER? |
Yes, use code MRWATERGEEK
|SPECIAL OFFER? |
Yes, Big Berkey bundle sale
The Best RO System For Removing Arsenic?
This article has established that reverse osmosis filters are effective at filtering harmful chemicals, contaminants, TDS, heavy metals, fluoride, lead, cysts, chlorine and pesticides and other toxic elements like arsenic from drinking water.
So you may want to start by getting a professional water test kit. Laboratory test kits are more accurate than cheap home test kits. You get the results online and they are now more affordable than ever.
My recommendation is to get an under-the-sink RO system.
They are very affordable, easy to install and set up (with a certain level of DIY plumbing skills).
Under sink RO systems require very minimum maintenance and the filters are easy to replace. They literally take a few seconds and often simply click into place.