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Drinking Water Safety

Is there Nitrate/Nitrite in My Drinking Water?

​​​​​What is nitrate/nitrite?

  • Nitrate and nitrite are molecules that are part of the nitrogen cycle. These molecules are forms of nitrogen, which are in soil and water. Nitrate and/or nitrite can collect in well water and when the levels are high, it can make people sick.
  • You can’t taste or smell nitrate and nitrite.

How can nitrate/nitrite affect my health?

Ingesting water with high levels of nitrate/nitrite can make people sick. Private drinking water sources (e.g., wells, dugouts, springs) can sometimes contain unsafe levels of nitrates/nitrites. If a baby drinks water with high nitrate/nitrite levels or it’s used to make formula, it might cause blue baby syndrome.

What is blue baby syndrome?

Blue baby syndrome (methemoglobinemia) is an illness that babies younger than 3 months can die from. It can be caused by drinking water with high levels of nitrate/nitrite. Methemoglobinemia affects how the blood carries oxygen. As it progresses, symptoms get worse and the skin starts to turn blue.

Symptoms of blue baby syndrome include:

  • blue skin (cyanosis)
  • weakness
  • headaches
  • trouble breathing
  • losing consciousness (coma)

Can anyone get methemoglobinia?

Babies younger than 3 months have the highest risk, but other people can get methemoglobinia. You might be at risk if you:

  • are pregnant
  • have a peptic ulcer
  • have chronic gastritis
  • are on dialysis
  • have certain genetic problems

Where is nitrate/nitrite found?

The most common sources of nitrate/nitrite include:

  • human sewage from septic systems not working right
  • livestock manure
  • fertilizer
  • natural minerals found in the aquifer

How does nitrate get into my water?

Nitrate and nitrite dissolve in water. If the aquifer that supplies your well has lots of these molecules, the water will carry them to your drinking water tap. How much depends on the source that’s contributing the most nitrate/nitrite. For example, if the natural source for the aquifer is high in nitrate/nitrite, the molecules will naturally collect and there is no way to stop this. If something on the surface is the main source, like livestock manure, think about managing manure better to stop this from happening. In some cases, if a well was poorly constructed, the problem can let contaminated surface water into the well. The contaminated water may also have high levels of nitrate/nitrite.

How much nitrate is too much?

Labs report these levels as nitrate and nitrite, or as nitrate-nitrogen (Nitrate N) and nitrite-nitrogen (Nitrite N). According to the Guidelines for Canadian Drinking Water Quality, drinking water is safe if it has less than:

  • 45 mg/L nitrate or 10 mg/L of nitrate-nitrogen (Nitrate N)
  • 3.2 mg/L nitrite or 1 mg/L nitrite-nitrogen (Nitrite N)

Is there any way to prevent methemoglobinemia?

It's important to test your water before a baby is expected. If using the health centre lab, test results can take several weeks – so plan early.

If your water supply has high nitrate/nitrite levels, install:

  • A point of use reverse osmosis system with NSF/ANSI 58 certification or a distillation treatment device at your drinking water tap. Reverse osmosis systems might not remove enough nitrates/nitrites that are a lot higher than the guideline (e.g., 100 mg/L Nitrate N).
  • an ion exchange unit for your whole house. However, the only health risk is your drinking water. It’s important to test and maintain the treatment system to make sure it works well.

Contact your local public health inspector to talk about ways to treat your water.

If you don't want to install a treatment system, use another water source for drinking water like:

  • water from an approved municipal system
  • bottled water
  • well water (recently tested for bacteria and chemicals)

Boiling water lowers the risk of it being contaminated with bacteria, but it does not remove nitrate/nitrite. Boiling will increas the nitrate/nitrite level in water.

If my water has high nitrate/nitrite levels, do I need to test for anything else?

Yes. If you have high levels of nitrate/nitrite in your water, you need to test it for bacteria.

It’s recommended to test private well water for bacteria 2 times a year. The best time to do this is in the spring (after snow has melted), after a very long dry spell, or after a very heavy rain. It’s also a good idea to test for bacteria any time the water tastes, smells, or looks different. Call your local health centre to find out how to test your private drinking water supplies for bacteria or you can find further information on this Alberta Health Services webpage and look under the water sampling section.

Current as of: March 13, 2018

Author: Environmental Public Health, Alberta Health Services