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Scott Winfield
Written by Scott Winfield
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Nitrates are naturally occurring compounds composed of nitrogen and oxygen. Consuming them in high levels via drinking water can cause serious health issues. So, the EPA recommends testing the nitrate levels in your water once a year.


Since you’re here, you’re probably wondering how to go about this. You’re in exactly the right place.

There are two ways to test your water for nitrate presence—DIY testing and sending water samples to a lab, and today, we’ll guide you through both. We’ll also discuss the EPA’s maximum limits for nitrates in drinking water, how nitrates get into water supplies, and how to prevent nitrates from contaminating your drinking water.

The Tolerable Limit Of Nitrates in Drinking Water

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

However, the EPA does allow states the discretion to set stricter nitrate limits. For example, a state may decide to set the maximum permissible limit to 8 mg/L rather than 10 mg/L.

How to Test Nitrates in Water

The best and most reliable way to test water for any kind of contamination, including nitrates, is to collect a sample from your faucets or well and send it to an EPA-certified water testing lab.

In return, the lab will provide you with a data sheet detailing all the contaminants present in your water supply, including the amount of each contaminant. If the nitrate levels in your water are higher than the EPA maximum limit or your state’s limit, you’ll need to start working on a solution (we’ll guide you through this later).

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

In such cases, you should 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, 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.

As per EPA guidelines, 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. Then, document the results in parts per million or milligrams per liter of nitrate. You can then multiply the measured nitrate concentration (in ppm or mg/L) by 4.4 to get the nitrogen content (in mg/L).
  8. Safely dispose of the sample that is reacting.

Of course, the methods used for DIY testing kits can vary so make sure you read the instructions carefully before you carry out the test.

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 used to manufacture agricultural chemicals like pesticides, fertilizers, and plant growth hormones. These chemicals often enter water supplies and private wells due to poor disposal and leaking septic systems and landfills.

The location and construction of a private well can also make it more susceptible to nitrate contamination. For instance, a well is more likely to be contaminated if it’s close to a septic tank.

Why is Testing for Nitrates Important?

As we mentioned earlier, the maximum nitrate limit in drinking water, according to the EPA, is 10 mg/L. This limit is stipulated in the 2012 United States Environmental Protection Agency regulations. This limitation 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.

Plus, a 2020 study 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 by promoting eutrophication and stimulating rapid algae and plant growth which 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, which include:

  • Controlling and minimizing the use of agrochemicals
  • Reducing stagnant and untreated bodies of water, whether it be for consumption or waste practices
  • Discouraging open-air defecation
  • Pressuring manufacturing industries to embrace good disposal practices
  • Making efforts to provide adequate sewage treatment

Personally, we can take the following actions:

  • Remove nitrates from water using reverse osmosis and other methods we’ll cover shortly
  • 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 nitrates in your water are above the EPA limit, there are a number of ways you can address this. The two best solutions for domestic water supplies are:

Reverse Osmosis

Whole House Reverse Osmosis System

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.

This means that tiny molecules like nitrates are unable to pass through the filter. As a result, the nitrate levels in the water are significantly reduced. In fact, some reverse osmosis systems can remove up to 99% of nitrates from drinking water. There are plenty of different types of reverse osmosis systems including whole-house, under-sink, and countertop units.

As the name suggests, whole-house systems purify water for your entire household. Under-sink units filter the water from a single faucet and countertop units aren’t typically connected to a water supply. To use a countertop unit, you need to fill it with water manually.



Distillation is a traditional water treatment method, but it’s still one of the most effective ways to remove nitrates from water.

In this process, the water is boiled in a container until it turns into 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. Once the distilled water cools and returns to its liquid form, the nitrates will no longer be present.

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 choose 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 healthy sources of nitrates?

One healthy source of nitrates is leafy green vegetables, such as spinach, arugula, and kale. Other sources include beets, beetroot juice, and celery.

Can nitrate-contaminated water 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. If the thyroid gland is blocked from using iodine, it can grow bigger and may even stop working.


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

To test your water, you can send a sample to an EPA-certified 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 your water, you need to address the issue quickly. Currently, reverse osmosis systems and countertop water distillers 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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