Does Reverse Osmosis Remove Nitrates From Water?

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Does Reverse Osmosis Remove Nitrates_Best Nitrate RO System Treatment

One of the most prevalent water contaminants most homeowners like you must deal with is nitrates. Nitrates are naturally occurring substances that do not have taste or odor. However, ingesting high doses of it from your drinking water can cause harmful effects on your and your family’s health. Thus, this got you thinking about putting up a RO water system in your home. But can reverse osmosis remove nitrates in water? 

In this post, you will learn more about reverse osmosis and discover how it can help remove nitrates in your drinking water. Read on to find out!

What Exactly Are Nitrates In Drinking Water 

When nitrogen binds with oxygen, a molecule known as nitrate (NO3) is formed. These organic compounds are naturally and synthetically occurring in the environment. You can find them in the atmosphere, soil, and water sources.  Unfortunately, nitrates can accumulate to dangerous levels in drinking water supplies.

Because nitrate is biodegradable and highly soluble in water, it can easily pass through the soil and groundwater. Nitrates can enter groundwater sources through rainwater, floods, and soil erosion.

Note that nitrogen is abundant in our surroundings, and they are essential to the health and growth of all organisms. However, nitrogen compounds can cause health problems and disease when consumed excessively.

How Do Nitrates Get Into Our Water Supply

Nitrates enter the water supply via agricultural run-off, industrial waste, fertilizer, and pesticide use, leaking septic tanks, and broken sewage systems [1]. Nitrate typically comes from:

  • Fertilizers used to grow crops: Rainwater can wash fertilizer away from farm soil and into waterways and lakes.
  • Plant decomposition: Nitrogen can be metabolized by naturally occurring microorganisms, resulting in nitrate deposits in the soil. 
  • Animal waste from commercial farms: Nitrates often enter water systems through improper animal waste disposal. 
  • Food processing waste: Food processing byproduct frequently contain nitrates that can be emitted into the local water or soil.
  • Industrial waste: Due to crop industrial waste, nitrates may be leached into groundwater supplies because they get deeply rooted in the soil. 
  • Well Water Sources: Nitrate concentrations in subterranean water systems used for well water can rise as natural nitrate deposits dissolve.
Does Reverse Osmosis Remove Nitrates_Nitrate Treatment Diagram Infographic
Biogeochemical cycle of nitrogen [1]

What is Considered High Nitrate Level In Drinking Water

The EPA’s limit for nitrate in public water systems is 10 mg/L. Thus, nitrate concentrations (in terms of nitrate-nitrogen) below 10 mg/L are considered acceptable for human consumption. 

What Are The Negative Health Effects Of Nitrate In Water


When more than 1% of the hemoglobin in a person’s red blood cells is in the form of methemoglobin, the result is a condition known as methemoglobinemia.

Nitrate can disrupt the way our blood distributes oxygen. Excessive exposure to nitrate can produce bluish or grayish skin discoloration and other health problems like weakness, increased heart rate, fatigue, and dizziness.

Infants are especially vulnerable to the effects of nitrate because their bodies respond differently to it. Babies younger than 6 months should not drink tap water or use it to create baby formula if nitrate levels are high.

Birth Defects

Extremely high nitrate levels in water supplies have been linked to an increased risk of limb deficiency,  congenital heart defects, and neural tube defects. Women who are pregnant or may become pregnant should not use the water for drinking or making foods that require a lot of water if the nitrate level is high.

Thyroid Disease

High nitrate levels in drinking water may raise the risk of thyroid disease. Nitrate has been shown to inhibit iodine uptake, which can affect thyroid function. Note that iodine is necessary for hormone production in the thyroid. Fatigue, extra weight, dry skin, hair loss, and goiters are some symptoms of low thyroid hormone levels (enlarged thyroid).


Nitrate contamination of drinking water supplies is a potential health hazard that may increase the likelihood of developing colon cancer. Nitrate may increase other compounds’ ability to cause cancer, or it may transform into chemicals that cause cancer in the body. However, there is no evidence that nitrates in drinking water cause any other types of cancer.

How Does Reverse Osmosis Remove Nitrates?

Pressurized water is used in reverse osmosis to force impurities out of a semipermeable membrane with tiny pores. These little holes that are 0.0001 micron function like a sieve, filtering out impurities in the water to leave behind just clean hydrogen and oxygen. 

Does Reverse Osmosis Remove Nitrates _ RO Nitrate Treatment Diagram Infographic

Ions, such as nitrates, can be removed from the water thanks to the membrane’s low micron rating. After going through the membrane, the purified water enters a holding tank. The membrane rejects the remaining pollutants washed away in the brine solution. 

How Much Nitrate Does Reverse Osmosis Remove?

Reverse osmosis has been shown to be effective in the removal of nitrates by a factor of 83-92%. Over 98% of waterborne pollutants may be removed by reverse osmosis, making it one of the most effective techniques of domestic water filtering.

Are Some RO Systems More Effective Than Others?

Know that nitrate removal efficacy can vary between brands. There are RO membranes that are better than others at getting rid of nitrates. Before purchasing a reverse osmosis system, be sure it has been approved by the NSF

RO membrane condition is just as critical as make and model when it comes to nitrate removal. Because of this, regular filter replacement and membrane cleaning are crucial parts of system maintenance. 

How To Test For Nitrates In Water At Home

Lab Test Your Water

Lab test from Tap Score is the most accurate way to test for nitrate in water at home. This water testing kit provides all the tools necessary to collect a representative sample of your tap water for analysis by a certified laboratory. 

This test is best done if you are (1) getting drinking water from a private well or spring, (2) expecting a baby, (3) having infants at home, (4) living near agricultural and animal farm areas, (5) having concerns about nearby industrial contamination.

Check Consumer Confidence Reports

View the results of recent water quality tests in your area by consulting the Consumer Confidence Reports (CCR).

Consumer Confidence Reports are a great resource for learning about the safety of your drinking water (CCRs). It is also known as water quality reports or drinking water quality reports.

What Other Contaminants Are Removed By Reverse Osmosis?

The nitrates in water aren’t the only contaminants that may be removed with reverse osmosis. RO can remove other contaminants from drinking water, such as 

Different Types Of Reverse Osmosis Systems


The RO filter can be installed in the space beneath the sink. This is connected to the water supply to guarantee that all household members can access safe drinking water. There are two types of under-sink units: those that use a tank and those that don’t.

A tankless reverse osmosis system could be the most convenient choice for those who reside in small homes with limited storage space. With this cutting-edge innovation, you won’t have to bother installing a big tank underneath your sink.


This RO system fits neatly on a kitchen counter and consists of separate filter units that work together to filter water through several different levels of purification. This filtration device can be installed on a sink’s faucet or container.

Whole House

It is a RO system installed directly where your house’s water supply enters. This system will filter and clean all the water that comes into your home, making it safe to drink. An RO membrane cartridge, a carbon post-filter, and a sediment filter are the components of a whole-house RO system.

Other Treatments To Remove Nitrates From Water

Fortunately, there are alternatives to reverse osmosis for removing nitrates from your home water. Let’s check them out one by one. 

Granular Activated Carbon (GAC or Charcoal Filters)

Activated carbon filters, also known as charcoal filters, use small fragments of carbon—either granules or blocks—that have been chemically treated to be incredibly porous. Activated carbon can decrease nitrate levels by 50-70%, depending on how good the filter is.

Ion Exchange Resins

Ion exchange resin uses a strong base anion exchange resin in the chloride form when removing nitrates in drinking water. As water travels over a bed of resin confined in a pressure vessel, nitrate and other anions in the water exchange with chloride in the resin, releasing chloride into the water.

Distilling Water

Distillation involves heating water to a boiling point and collecting the resulting water vapor while leaving the nitrates behind. Although effective, this method can be time-consuming and must be de-scaled frequently. The upside is because distillation is a natural process, you can make distilled water at home for free.

When comparing reverse osmosis vs distilled water, it really depends on what you intend to use the water for. Distilled water has many popular uses due to its purity, like its use in CPAP machines, infant formula, humidifiers, and more.

FAQs For Reverse Osmosis PFAS Removal

How do I prevent nitrates from getting into my water? 

  • Reduce your fertilizer and pesticide use.
  • Improve the soil’s health by introducing techniques like cover crops into a crop rotation.
  • Establish a DWM system (Drainage Water Management), especially if you own a farm. 
  • Make sure to have your water source tested regularly.
  • Ensure your water source is protected from high-nitrate sources. 

Can nitrates affect adults?

The potential associations between nitrate exposure and health include increased heart rate, nausea, headaches, and abdominal cramps. It can also cause methemoglobinemia, birth defects, thyroid problems, and colon cancer. 

Are nitrates in water harmful?

Nitrates in water are harmful as studies have shown a high correlation between nitrate exposure and methemoglobinemia, birth defects, thyroid disease, and cancer. 

How to remove nitrate from water naturally?

Reverse osmosis, distillation, and ion exchange resin are all viable methods for purifying water from nitrates. Sediment filters, carbon filters, and the hollow fiber membrane of an ultrafiltration system are all ineffective at removing nitrates.

Does boiling water remove nitrates?

No, boiling water does not remove nitrates from water. Additionally, some water will evaporate during the boiling process which leads to a higher concentration. If nitrates have been detected in your water supply, you should switch to another, safer option. At the very least, bottled water would be your next best alternative.

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. Nitrate Water Contamination from Industrial Activities and Complete Denitrification as a Remediation Option, MDPI
  2. Drinking Water Nitrate and Human Health: An Updated Review, National Institute Of Health
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