Nitrate in well water: What is it, and what do you do? – Courtesy of the NGWA

Nitrates are nitrogen-oxygen compounds that serve as essential nutrients for plants, which absorb them from the soil. The largest source of nitrates are fertilizers used on crops. Animal and human waste also contains nitrogen in the form of ammonia.

Nitrate also is generated by:

  • Decomposing plant and animal materials
  • Sewage
  • Septic systems
  • Industrial effluent
  • Landfills

What are the health risks?

The greatest health concern is “blue baby syndrome” or methemoglobinemia. The syndrome is seen most often in infants exposed to nitrates from drinking water used in baby formula. Infants ages 0 to 3 months are at highest risk. The syndrome affects the ability of the baby’s blood to carry oxygen to body tissues.


Other children and adults can withstand higher levels of nitrates than babies. However, exposure to higher levels of nitrates has been associated with increased incidence of cancer and other issues in adults.


How is health risk measured?

The U.S. Environmental Protection Agency  has a maximum contaminant level for nitrate of 10 parts per million (milligrams per liter) as nitrogen.


How can nitrates reach my water supply?

Excess nitrates not used by plants can be carried through the soil to groundwater in a process called leaching. Nitrates are very soluble and do not bind with soil.


Is my private well at risk?

Nitrate is tasteless and odorless. The way to know if your well water is at risk is to have it tested for nitrate. You may be at greater risk if:

  • Your well system is shallow
  • It’s near a septic system, agricultural land or animal feedlots
  • Nitrates have entered the soil due to heavy rains, flooding, chemical spills or sewage system failures


Why type of treatment solutions are available?

The U.S. EPA has approved certain methods for removing nitrates, including:

  • Reverse osmosis: This works best on point-of-use systems, which generally are used in places such as the kitchen sink where water is used mostly for drinking and cooking.
  • Ion exchange: Along with a water softening system, an ion exchange system can provide a whole-house solution for nitrate contamination.


To learn more about water testing and treatment, visit