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What is Nitrate?

Nitrate is a compound that forms when nitrogen combines with oxygen or ozone. Nitrates are made in large amounts by plants and animals and can also be released in smoke and industrial or automotive exhaust. Naturally occurring nitrate can be found in groundwater and surface water at levels that do not generally cause health problems.

Nitrate in Private Wells, New Mexico

Levels of various naturally-occurring and man-made constituents in New Mexico groundwater including nitrate, might be elevated above the Environmental Protection Agency (EPA) Safe Drinking Water standard of 10 milligrams per liter (mg/L). Ongoing drought conditions and aquifer mining have raised further concern that increases in constituents may occur in the absence of significant ground water recharge events. To assure that the water is safe for human consumption, well owners should periodically test their wells.

The information available on this section, including the maps, demonstrates nitrate found in tested private wells in New Mexico based on the data available from various sources.

Interpolated groundwater nitrate concentrations (mg/L) from private wells data Jun. 2004 - Apr. 2018
Average nitrate distribution in groundwater by county (mg/L) from private wells data Jun. 2004 - Apr. 2018
Percentage of samples exceeding the EPA MCL of 10 mg/L for nitrate: private wells data Jun. 2004 - Apr. 2018.

Nitrate Sources

Although naturally occurring nitrate can in groundwater and surface water does not generally cause health problems, high levels of nitrate in water can indicate contamination with human or animal waste therefore It is important to also test your water for coliform and E. coli bacteria. Sources of nitrates in drinking water can include runoff from fertilizer use, leaking from septic tanks, sewage or erosion of natural deposits.

Nitrate and Health

Nitrogen is essential for all living things, but high levels of nitrate in drinking water can be dangerous to health. The most common way of ingesting nitrates is through drinking water. Once taken into the body, nitrates are converted to nitrites.

Nitrate toxicity can cause illness, with the most vulnerable population being infants. Infants below four months who drink water containing nitrate above 10 mg/L could become seriously ill with blue baby syndrome (methemoglobinemia). Symptoms of this nitrate toxicity include shortness of breath and bluish skin coloring.

Nitrate in Private Wells: Testing, Prevention and Treatment

If your water comes from a private well the only way to know if there is nitrate in the water is to test it (springtime is best!). If nitrate levels are above 10 milligrams per liter (mg/L) consider appropriate treatment/filtration options, or consuming water from a different source.

Keep possible contaminant sources a safe distance from any well. If you live in an area with a high density of private wells, you can be a good steward by not disposing of manure and chemicals on your property and by keeping possible contaminant sources on your property a good distance from the well head on your neighbor's property.

Other tips include:

  • Make sure your well has a sanitary cap or seal.
  • Make sure the ground is sloped away from the well, so water flows away from the well head.
  • Make sure the casing extends 18 inches above the land surface (NMAC 19.27.4).
  • Keep your septic system well maintained.
  • Prepare when flooding is likely by: Using sandbags to divert water away from the well head and protecting vented areas with tarp or duct tape.

Treatment tips

Treatment of water can vary depending on water chemistry. It is important to test your water before choosing a water treatment system. A licensed well contractor or water quality professional may help with choosing the right treatment system for your water chemistry. For additional guidance choosing a treatment system certified to remove Nitrate consult with the Water Quality Association or at 630-505-0160 or NSF international (formerly the National Sanitation Foundation) or at 1-800-NSF-MARK (1-800-673-6275).

Public Water Systems and Nitrate

If your water comes from a public water supply, it will regularly be tested for nitrate. Public water systems should not have nitrate above 10 milligrams per liter (mg/L) to comply with the United States Environmental Protection Agency (EPA) Safe Drinking Water Act standards. See the environmental indicator report and queries in the "Explore Related Data" section below for nitrate concentration in community water systems.

For more information on public water systems, contact

  • Your community water system by telephone
  • Look up your community water system online through the New Mexico Environment Department (NMED) Drinking Water Watch
  • Call the NMED Drinking Water Bureau, TOLL FREE 1-877-654-8720

Notifiable Diseases or Conditions in New Mexico (N.M.A.C

Infant methemoglobinemia is reportable to the New Mexico Department of Health. Report to Epidemiology and Response Division, NM Department of Health, P.O. Box 26110, Santa Fe, NM 87502-6110; or call 505-827-0006.