Nitrate in Well Water

Nitrate is a chemical found in most fertilizers, manure, and liquid waste discharged from septic tanks. Natural bacteria in soil can also convert nitrogen into nitrate. Rain or irrigation water can carry nitrate down through the soil into groundwater. Your drinking water may contain nitrate if your well draws from this groundwater.

How does nitrate affect health?

Drinking water with high levels of nitrate can affect how blood carries oxygen. Infants are particularly at high risk of developing a serious health condition due to the lack of oxygen. This condition is called blue baby syndrome. Some people may also be susceptible to health problems from nitrate.

Sources of Nitrate(5)

How much nitrate is too much?

The safe drinking water standard for nitrate is 10mg/L. If your water has nitrate level above 10mg/L, you should use bottled water or water from a safe source for drinking, preparing infant formula, and washing and cooking food.

How can I tell if my well water has nitrate?

Testing your well is the only way to know if there is nitrate in your well. However, the following types of wells may be at greatest risk of contamination:

  • Shallow wells
  • Poorly sealed or poorly constructed wells
  • Wells that draw from shallow aquifers

How can I test my well water?

Contact a certified laboratory to test your well water. The laboratory will provide specific instructions on how to collect, store, and send the sample. Most accredited labs in Yakima County charge $40 to $55 per test. To find a certified lab near you, visit

What else should I do if the nitrate in my well water is over 10mg/L?

  • Use an alternative source of drinking water such as bottled water.
  • Do not try to boil the water to remove nitrate. Boiling your water may increase the concentration of nitrate in the water.  
  • Review our water treatment flyer or contact an Environmental Health Specialist at 509-249-6508 to learn more about potential sources of contamination and water treatment options.