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How to Test Nitrates in Water (Step-by-Step)

Scott Winfield
Last Updated on
by Scott Winfield

Nitrates are naturally occurring compounds that are composed of nitrogen and oxygen elements.

However, consuming them via drinking water can be detrimental to the human body. If their presence in drinking water exceeds 10mg/L, it can lead to toxic reactions in human bodies, resulting in weakness, dizziness, and fatigue. So, to prevent nitrate contamination, the Environmental Protection Agency advises all Americans to test their water for nitrates at least once a year.

In this article, we’re going to explain how nitrates get into water, why it’s important to keep an eye on the nitrate levels in your drinking water, and how you can test your water for nitrates, so you’re confident it’s safe for you to drink.

The Tolerable Limit Of Nitrates in Drinking Water

The Environmental Protection Agency (EPA) set the maximum permissible limit of nitrate in drinking water at 10mg/L (10 milligrams of nitrate per litre of drinking water). This means that water with nitrate levels at or below 10mg/L is considered safe to drink.

How to Test Nitrates in Water

The best and most reliable way to test water for any kind of contamination, including nitrates, is by collecting a water sample from your faucets or well and sending that sample to an EPA-certified water testing lab

In return, the lab will provide you with a data sheet that details all the contaminants present in your water supply, with their amounts. After that, you can see whether any of them pose a risk and start working on solutions.

That said, not everyone has the time to wait for a certified lab to test their water and present them with a detailed list. Some might need to conduct an immediate test to prevent exposure.

In such cases, you should first contact your local Environmental Services or Soil and Water Conservation District and ask whether they have a nitrate testing kit.

If this doesn’t work either, you can purchase a water testing kit online or from a hardware/appliance store nearby and conduct your own test as instructed on the package of the test kit. However, as this is not the most reliable method for testing nitrate levels in water, we still advise you to send a water sample to a certified testing lab at the first opportunity.

Lastly, as we said in the intro of this article, no matter how much trust you have in the purity of your water supply, you should have your water tested for nitrates at least once a year.

DIY Nitrates Testing at Home:

Here’s another method to test for nitrates at home:

  1. Collect the sample water and put it into the sample bottle.
  2. Place about 2.5 milliliters of sample water into a clean test tube.
  3. Top this with Mixed Acid Reagent to 5.0 milliliters.
  4. Let it rest for about 3 minutes to react.
  5. Using a 0.1-gram spoon, scoop a level amount and leave it for about 9 minutes.
  6. Place the test tube in a comparator of nitrate-nitrogen, then check the color of the sample compared to the color of the standard.
  7. Document results in parts per million or milligram per liter of nitrate. Nitrogen is then converted to a milligram per nitrate after multiplying it with a factor of 4.4
  8. Safely dispose of the sample that is reacting.

How Nitrates Get Into Water

As nitrates are naturally occurring in the environment, they can easily leach into groundwater resources from nitrate-rich soil or through surface water runoff.

Additionally, nitrates are amply used in the making of farming chemicals like pesticides, fertilizers, and plant growth hormones. When such chemicals get near private wells after poor disposal of industrial waste or because of leaking septic systems and landfills, a significant amount of nitrates is let loose around vital sources such as water supplies.


Other contributing factors can be the location of the well and how it’s constructed. There’s an especially high chance for a water well to be contaminated with nitrates if it’s close to a septic tank.

Why is Testing for Nitrates Important?

For water to be considered safe for consumption, the 2012 United States Environmental Protection Agency regulations stipulates that the nitrate presence in it shouldn’t exceed 10mg/L. This particular number aims to protect against blue baby syndrome, a condition that causes babies’ skin to turn blue due to poorly oxygenated blood and a nitrate-rich diet.

But, blue baby syndrome is not the only health condition associated with nitrates. According to the Minnesota Department of Health, high nitrate toxicity in humans causes methemoglobinemia, elevated heart rate, muscle weakness, ptyalism, and depression.

Side effects of nitrate toxicity include hypotension, arrhythmia, headache, flushing, and dizziness. Furthermore, nitrate consumption via drinking water can have lethal repercussions and precipitate colon and colorectal cancers.

A 2020 study, on the other hand, suggests that colon and colorectal cancers aren’t the only cancers caused by nitrates. High amounts of nitrates, when ingested through drinking water, tend to mix and combine with endogenous chemicals such as amines and amide in the gastrointestinal tract to form N-nitroso compounds like nitrosamines.

Nitrosamine in the alimentary canal reacts with internal linings in a carcinogenic manner, which can ultimately result in tumors and carcinoma. The nitroso compounds are also linked to cancers in the lungs, bladder, liver, skin, trachea, bone, thyroid, myelocytic leukemia, and T and B cell lymphomas.Elevated nitrate levels also affect aquatic life, promoting eutrophication, stimulating rapid algae and plant growth that has a negative effect on the plankton population.

Preventing Nitrates From Contaminating Water

Considering all the health effects of nitrates in drinking water, we should do our best to prevent contamination. To that end, there are things we can do socially and personally.

Socially, we can raise public awareness about nitrate contamination and urge authorities to take the necessary measures:

  • Control and minimize the use of agrochemicals
  • Reduce stagnant and untreated bodies of water, whether it be for consumption or waste practices
  • Discourage open-air defecation
  • Pressure manufacturing industries to embrace good disposal practices
  • Make efforts to provide adequate sewage treatment

Personally, we can take the following actions:

  • Remove nitrates from water by denitrification processes such as physicochemical processes and biological processes
  • Discourage giving food, like beets and spinach, and water that’s high in nitrates (more than 10mg/L) to infants when weaning
  • Avoid food and drink items that have nitrogenous preservatives

Best Treatment Methods For Nitrates in Water

If the tests show more than 10mg/L of nitrates in water, you should immediately consider solutions. Although there are many industrial-level ways to remove nitrates, like anion exchange, only two of those are applicable for household use:

Reverse Osmosis

Reverse osmosis is a water filtration process in which the contaminated water is pushed through a semi-permeable membrane that has microscopic pores of 0.0001-micron size. Not even the tiniest molecules, including nitrates, can pass through these pores, so this is an effective method for getting nitrate-free water. You can either install a whole house reverse osmosis system that purifies all the water in your household, or you can specifically go for a countertop or under-the-sink device that will only treat your drinking water.


Distillation is a traditional water treatment method, but it’s still one of the most effective ways to remove nitrates form water. In this process, the water is boiled in a container until it’s all vapor. The vapor is then transferred to another container, where it’s cooled and condensed.

In the vapor state, the contaminant particles can’t find any surfaces to cling to, so they evaporate. At the end, once the distilled water cools and returns to its liquid form, there’s no nitrate present in it. Although whole-house distillers are expensive, industrial-strength devices, you can still find some great countertop distillers on the market. Just make sure that the device you opt for is capable of dealing with nitrates by consulting the manufacturer before you purchase.

Frequently Asked Questions

Is nitrate toxicity dangerous for young children?

Yes, high amounts of nitrates cause a complex condition in infants that results in methemoglobinemia (which happens when a baby’s gastrointestinal tract converts nitrate to nitrite and starts producing methemoglobin), leading to a syndrome called blue baby.

Are there benefits of nitrates in the human body?

Yes, in the gastrointestinal tract, nitrates have been found to have antimicrobial properties, while endogenous nitrous oxide has been seen to act as a vasodilator in the cardiovascular system.

What is the relationship between nitrates and diabetes?

Nitrates are inversely related to diabetes. A 2013 study shows that a high nitrate intake has a therapeutic effect on individuals with Type 2 Diabetes.

However, the study also emphasizes that the source of nitrate intake should be vegetables that naturally contain it and not as a result of contamination. So, in no way does that mean that nitrate-contaminated water is beneficial for humans and should be consumed untreated.

What are some good sources of nitrates?

Some good sources of nitrates are leafy green vegetables, such as spinach, arugula, and kale. Other sources include beets, beetroot juice, and celery.

Is nitrate toxicity lethal to the respiratory system?

Yes, a high nitrate concentration in inhaled air tends to irritate the cells along the airway and results in an increased mucous secretion that blocks the gaseous exchange system. Consequently, inhalation and exhalation are impaired, and the individual produces a wheezing sound characterized by asthmatic attacks.

Can poisonous nitrate amounts affect pregnancy?

Yes, nitrate toxicity has been connected to abortions where stillbirths, low birth weights, slow weight gain, and deaths have been evidenced by teratogenicity caused by N-nitroso compounds formed from drinking contaminated water.

The adverse effects of methemoglobinemia caused by lethal nitrate doses impair fetal growth. The transplacental passage of these toxins leads to congenital disabilities.

How does nitrate poisoning cause thyroid malformations?

Consuming elevated concentrations of nitrates can inhibit iodine uptake in the thyroid gland. The impairment of iodine trapping in the thyroid gland is goitrogenic and may result in malformations in the gland.


Although nitrates are naturally found in common dietary sources like veggies, a more than 10 mg/L presence of them in drinking water can cause various health conditions like blue baby syndrome in infants and many forms of cancer in adults. To prevent such consequences, EPA recommends testing water at least once a year for nitrate levels.

To that end, you might send a water sample to an EPA-certified water testing lab, ask local departments whether they have relevant water testing kits, or purchase your own kit online.

If the tests show an alarming presence of nitrates in water, you may start working on solutions. Currently, a reverse osmosis system or a countertop water distiller are the best household solutions to deal with nitrates.

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Scott Winfield
Scott Winfield
My name is Scott Winfield and researching and writing about water filters and other strategies to purify water has become my full time passion in recent years. I'm glad that you found our site and you can look forward to authoritative and well researched content here to help you get the best in water.
1 Comment
  1. I appreciate you mentioning that one should compare the sample’s color to the standard’s color. I have moved into a new home and want to filter the water to improve the quality of the drinking water. I intend to hire a water nitrate filtration service to put in my home.

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