Does Reverse Osmosis Remove Iron From Water?

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Does reverse osmosis remove iron from water_RO iron treatment for well water

The water that flows from our taps is a vital part of our everyday lives. We use it to drink, cook with, and bathe in. But what many people don’t realize is that the water they are using may not be as clean and safe as they think. In fact, it may contain harmful contaminants like lead, arsenic, and pesticides.

One way to remove these harmful contaminants from your water is by using a reverse osmosis system. But does reverse osmosis remove iron from water? Let’s take a closer look.

What Exactly Is Iron?

Iron is a mineral that is found in water, soil, and air. It is an important component of hemoglobin, which is what gives our blood its red color. Iron is also necessary for our bodies to make new cells and repair damaged ones.

While iron is an essential nutrient, too much of it can be harmful. When water contains high levels of iron, it can cause a number of problems, including:

  • Staining of laundry, dishes, and sinks
  • Discoloration of water
  • Minerals buildup in plumbing fixtures and appliances
  • Bad taste in drinking water
  • Unpleasant odor

Types of Iron In Water

We are all familiar with iron found in animal and plant-based products. However, there are two main types of iron found in water:

Ferrous Iron

Ferrous iron (Fe2+) is the most common type of iron found in water. It is typically found in wells that have been drilled into bedrock or limestone. Ferrous iron is not visible in the water, but it can cause staining and discoloration [1].

Ferric Iron

Ferric iron (Fe3+) is less common than ferrous iron, but it is more likely to cause problems. Ferric iron is typically found in surface water sources, like lakes and rivers. Ferric iron is visible in the water as red or orange particles.

Additionally, there are two types of iron that are typically less common, which are iron-oxidizing bacteria and organic iron (tannins).

How Iron Gets Into Our Water Supply

Have you ever wondered why your water sometimes has a red, brown, or yellow tint? It’s likely due to high iron levels, which can get into our water supply from a variety of sources. Iron may leach into water from volatile organic chemicals that come from rocks and minerals in the ground, or it may be present in groundwater that comes into contact with rusting pipes [2]. Iron is a naturally occurring element, and small amounts are actually essential for our health.

The EPA has suggested limits on the amount of iron allowed in public water supplies, and levels above this limit may require treatment. The EPA standard for iron in drinking water is currently 0.3 mg/L. However, heavy iron contamination exceeding 10 mg/L is less common and should be treated. If you suspect that your drinking water has high levels, you should test your water and utilize an iron removal system.

Potential Health Impacts Of High Iron Levels

Too much of anything is usually not good for you, and that also goes for iron. Although our bodies need iron to function, elevated iron levels can actually have negative side effects liike:

  • Gastrointestinal Damage
  • Nausea
  • Vomiting
  • Diarrhea
  • Liver Damage

The amount of iron that is considered safe for daily intake depends on a person’s age and sex. For example, the recommended dietary allowance (RDA) for adult males is 8 mg/day and 18 mg/day for adult females. Anything over the RDA for a long period of time and the iron can accumulate and cause severe damage to the brain and liver [3].

Another issue when it comes to iron is iron bacteria. This type of bacteria is usually found in water that has a high concentration of iron. Although it’s not harmful to consume water with iron bacteria, it can cause staining and discoloration.

How Does Reverse Osmosis Remove Iron?

The reverse osmosis process works by forcing water through a semi-permeable membrane with pores that are only 0.0001 micron. This membrane is designed to allow water molecules to pass through while stopping larger contaminants like iron. Over time, it is necessary to flush the system clean of contaminants so it can operate effectively, leading to a small amount of waste water [4].

Does Reverse Osmosis Remove Iron From Water_Reverse Osmosis Iron Treatment Process Diagram Infographic

Importantly, when filtering iron, a reverse osmosis system should include pre-filtration to help protect the membrane from fouling prematurely. A typical system will consist of three (or more) filtration stages:

  1. Pre-Sediment Filter: Remove sediment, dirt, and other larger particles
  2. Semipermeable Membrane: Remove heavy metals, pesticides, radium, PFAS, and much more
  3. Carbon Post Filter: Remove remaining impurities and get rid of bad taste and odors

A system may contain more filters like a remineralization filter or a UV purifier to help destroy well water bacteria.

How Much Iron Will Reverse Osmosis Remove?

Reverse osmosis can remove dissolved iron from water. The semipermeable membrane effectively removes up to 99% of all iron in water, including ferric, ferrous, and organic types.

Furthermore, the reverse osmosis process can remove hydrogen sulfide, chloramines, chemicals, lead, fluoride, TDS, microplastics, and thousands of other contaminants. If the system has an ultraviolet light purifier, it will also sterilize 99.99% of microorganisms, iron bacteria, and viruses.

The amount of iron that a RO iron filter can remove depends on a few factors, including the type of system, the quality of the water, and the amount of iron in the water. However, if you have a high concentration of iron in your drinking water, you may need to use a specialized iron removal system.

On the other hand, if you have a low concentration of iron in your water, a standard RO system may be enough to treat excessive iron.

Are Some RO Systems More Effective than Others?

Different RO systems have different levels of performance when it comes to iron filters. Some systems are designed specifically for removing iron, while others may not be as effective.

The type of dissolved iron found in well water can destroy the reverse osmosis membrane without an iron pre-filter protecting it. Iron filters designed for well water should contain kinetic degradation fluxion (KDF) filter media that will effectively remove iron from water [5].

Home filtration systems bearing industry certifications are more desirable. The highest certification is earned from the National Sanitation Foundation (NSF). Specifically, reverse osmosis systems and components fall under the purview of NSF 58. Systems that carry this certification have been rigorously tested for filtration effectiveness.

Do RO Systems Remove Iron From Well Water?

For many people who get their water from a well, an RO system is a great way to remove impurities and make the water safer to drink. But we often get asked whether or not an RO system can remove iron from well water. The answer is yes, RO systems are effective at removing iron from well water, in addition to magnesium and hydrogen sulfide.

One aspect to consider is that well water commonly has low water pressure. For a reverse osmosis system to function effectively, they require high pressure to force the water through the membrane filter. This is why it is important to use a system with an integrated booster pump, or install a separate booster pump, so PSI is within the operating threshold.

Secondly, if the iron concentration is very high (exceeds 5 PPM), it is recommended to accompany the RO system with a pre-filtration solution to prevent the RO membrane from fouling.

Does Reverse Osmosis Remove Iron Bacteria From Well Water?

Iron bacteria are small, single-celled organisms that get their energy by oxidizing dissolved iron. This can cause a rust-colored stain on surfaces and a musty smell in the air. If you have iron bacteria in your well water, you may be wondering if a RO filter system can remove them.

Reverse osmosis filtration is designed to remove impurities from water, and iron bacteria are effectively removed in the reverse osmosis process. As an additional layer of purification, many systems include a UV light to sterilize 99.99% of iron bacteria and microorganisms.

How To Maintain A Reverse Osmosis Filter For Iron

In order to maintain your RO system and keep it working effectively, it is important to replace the water filters on a regular basis.

Typically the pre and post-filter of an RO unit need to be replaced every 3 – 6 months, while the RO membrane needs to be replaced every 12 – 24 months. In addition, it is a good idea to clean the system regularly with a vinegar solution.

Depending on the type of system you have and the level of iron in your water, the filter replacement timelines can vary.

Where Is A Reverse Osmosis System Installed?

RO filtration units can be installed in a variety of locations, depending on your needs. Some of the widely used installation points include:

  • Point Of Use: A point-of-use system is the most common style. These are also referred to as Undersink units. They are easy to install under the sink and can be used to provide filtered water for cooking, drinking, and cleaning. Undersink RO units can be either tank based or tankless.
  • Point Of Entry: Also referred to as a whole-house RO, they are for those who want the entire house to have access to clean, filtered water. Whole-house units are installed at the point-of-entry for the main water supply of the home.
  • Countertop: If you’re looking for a more affordable option, a countertop reverse osmosis system might be right for you. These systems are small and can be easily setup on your kitchen counter.
  • Portable: Portable units are a great choice for those who want the convenience of filtered water without the hassle of installation. These systems can be placed on a countertop or table, and they come with their own storage tanks.

How To Test For Iron In Water

If you suspect that you have iron in your drinking water, there are a few ways to detect it.

Home Water Test Kit

Getting a home water test kit is the only way to know the iron levels of your water for sure. To get the most robust and accurate results, a lab test kit from Tap Score is the best solution. The company tests for more than 100 contaminants in water. You simply collect a sample using the kit and send it back to a certified laboratory to test your water. 

Local Water Quality Reports

To check the iron levels in your area, you can visit the Consumer Confidence Reports database. Since the EPA requires all local water suppliers to generate an annual local water quality report for consumer transparency, this will have data on a number of contaminants in your local water. 

Although this method is quick and easy, it doesn’t give you precise data for your home. The best solution is to get a home test kit as there are a wide variety of things that can affect each individual home.

Drawbacks of Using Reverse Osmosis For Iron Treatment

While RO systems are an effective way to remove iron from your water supply, there are a few drawbacks to using this method.

  • Waste Water: One of the biggest drawbacks to the RO process is the amount of water required to flush the system clean. For every gallon of filtered water you get from an RO water filter, two to three gallons of water are wasted.
  • Relative Costs: Reverse osmosis systems have a higher relative price than traditional filters. Depending on the type of system you have and the level of iron in your water, you also may need to replace the iron filter every few months which can add up. However, the filtration performance of reverse osmosis is unparalleled.
  • Removes Healthy Minerals: One final drawback to using reverse osmosis systems is that they remove healthy minerals from your drinking water along with iron. While this isn’t necessarily a bad thing, it is something to be aware of.

FAQs For Reverse Osmosis Iron Removal

Does reverse osmosis remove iron and manganese?

Yes, RO systems are effective at removing both iron and manganese from your well water supply. Your water will likely have a higher pH level after being filtered by an RO iron removal system, which can help to prevent rust and corrosion.

Does Brita remove iron?

Brita filters are designed to remove a variety of impurities from your water but do not remove iron as well as RO units. Using a Brita filter is a convenient and affordable way to get aesthetically appealing water.

What is the best iron removal media?

There are a variety of iron removal media that can be used, including greensand, anthracite, and activated carbon. The best media for your needs will depend on the type of water you have and the level of iron present.

Article Sources

Freshnss uses only the highest-quality sources to support the facts used in our articles including: government organizations, independent studies, peer-reviewed journals, and lab testing results. Read our editorial review guidelines here to learn more about how we verify and fact-check our writing to keep our content reliable, accurate, and trustworthy.

  1. Essentials of Medical Biochemistry: Metabolism Of Iron And Heme, N.V.Bhagavan, Chung-EunHa
  2. Iron In Well Water, Minnesota Department Of Health
  3. What Happens if You Take Too Much Iron?, Medical and Life Sciences News
  4. A Guide to Drinking Water Treatment Technologies for Household Use, Centers For Disease Control And Prevention (CDC)
  5. Using KDF Material To Improve The Performance Of Multi-Layers Filters In The Reduction Of Chemical and Biological Pollutants in Surface Water Treatment, South African Journal Of Chemical Engineering
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