Rural America - Nitrate and Your Drinking Water- A Hidden Danger?

Brian Oram, Licensed Professional Geologist
Featured Water Professional

Nitrate-nitrogen (NO3-N) or Nitrite-nitrogen (NO2-N) in groundwater or your drinking water may result from point sources such as sewage discharges and livestock facilities or non-point sources such as fertilized cropland, parks, golf courses, lawn and gardens, septic systems, agricultural areas, or naturally occurring sources of nitrogen.  Because nitrate is highly leachable and readily moves with water through the soil profile, large recharge events, concentrated runoff,  excessive rainfall, or over-irrigation can cause the nitrate to be leached from below the plant's root zone and may eventually reach the groundwater table and your water well or local spring. 

Therefore, if you live in a historically or currently active agricultural-dominated community or in parts of Arizona, California, Illinois, Iowa, Kansas, Minnesota, Nebraska, Nevada, New Jersey, New Mexico, New York, Ohio, Pennsylvania, Utah, Texas, Washington, and Wisconsin, the groundwater and drinking water sources may have a nitrate concentration of over 5 mg/L (“The Nitrate Warning Level”). The EPA maximum contaminant level for nitrite (NO2-N) is 1 mg N/L or 1000 ppb (Nitrite Warning Level: 0.5 mg N/L) and for nitrate (NO3-N) it is 10 mg N/L or 10,000 ppb (Nitrate Warning Level: 5 mg N/L).

USGS Nitrate Map

(Image Source)

The primary health hazard from drinking water with nitrate-nitrogen occurs when nitrate is transformed to nitrite in the digestive system. The nitrite oxidizes the iron in the hemoglobin of the red blood cells to form methemoglobin, which lacks the oxygen-carrying ability of hemoglobin. This creates the condition known as methemoglobinemia (sometimes referred to as "blue baby syndrome") in which blood lacks the ability to carry sufficient oxygen to the individual body cells, causing the veins and skin to appear blue. In infants under six months of age, the enzyme systems for reducing methemoglobin to oxyhemoglobin are incompletely developed and methemoglobinemia can occur. This also may happen in older individuals who have genetically impaired enzyme systems for metabolizing methemoglobin.

For the record: You may also be exposed to nitrates if you eat leafy green vegetables and cured meat. It has been suggested that there is a link between nitrate and adverse reproductive effects; it may also negatively influence thyroid function. The Agency for Toxic Substances and Disease Registry (ATSDR) state the following:

  • “Acute acquired methemoglobinemia is the most important adverse health effect caused by excessive nitrate/nitrite exposure.
  • The known toxic effects from nitrate exposure result from the conversion of nitrate to nitrite.
  • The effects of nitrite (NO2-) are the same whether nitrite-containing compounds are ingested or inhaled, or nitrite is produced in vivo from nitrate.
  • Maternal exposure to environmental nitrates and nitrites may increase the risk of pregnancy complications such as anemia, threatened abortion/premature labor, or preeclampsia.
  • Angina-like pain, MI and cardiovascular death have been reported in explosive industry workers exposed to nitroglycerin and other organic forms of nitrates.
  • Epidemiological investigations and human toxicological studies have not shown an unequivocal relationship between nitrate intake and the risk of cancer.”

The EPA maximum contaminant level for nitrite (NO2-N) is 1 mg N/L or 1000 ppb and for nitrate (NO3-N) is 10 mg N/L or 10,000 ppb (EPA Health Advisory), but one 501(c)(3) organization, the Environmental Working Group (EWG), has recommended a nitrate standard as low as 0.14 mg/L that is reportedly based on a one-in-a-million cancer risk . Our primary concern with this recommendation is that the ATSDR finding is “Epidemiological investigations and human toxicological studies have not shown an unequivocal relationship between nitrate intake and the risk of cancer,” so we recommend using 50% of the EPA drinking water standard as a warning limit. Therefore, the warning limits are 5 mg NO3-N/ L and 0.5 mg NO2-N/L and if the drinking water has detectable levels of nitrite (NO2) we recommend getting the water tested for ammonia, surfactants, E. coli., Total Coliform, and Total Dissolved Solids).

Our Recommendation

1. Get Your Drinking Water Tested using Level 2 or Level 3 monitoring.  This is especially true if you are located in an agricultural area or an area that relies on the use of land-based wastewater management, i.e., septic systems.

2. Regularly Monitor the Quality of your Drinking Water.

3. If you have an infant or are planning to get pregnant, or the water is used by an elderly person with an enzyme disorder, you may want to consider the installation of a point-of-use water filtration system for nitrate and nitrogen-related compounds.

4. Monitor the Nitrate and Nitrite level of your drinking water using Level 2 and Level 3 testing.

Get Tested | Level 2 Self-Monitoring at Home

Hanna Instruments High Range Nitrate Checker HI782

Hanna Instruments HI764 Marine Nitrite Ultra Low Range Checker HC

Industrial Test Systems Store Test Strips Nitrate/Nitrite Nitrogen, PK50

Safe Home City Water or Well Water at Home Kit

Leaping Lynx at Home Drinking Water Testing Kit for Well & Tap Water

Get Tested | Level 3 Informational Water Test

Water Check Basic – Well Water

City Water Check Basic – City Water

Get Treatment

Point-of-Use – Water Treatment Systems

Before installing any pretreatment system, we would strongly recommend Level 3 esting.  Common water treatment systems for the reduction of nitrate and nitrite in drinking water includes: Anion Exchange resins (whole-house or point-of-use devices), Reverse Osmosis (point-of-use device), and distillation systems.  Boiling the Water – WILL NOT address problems or concerns related to nitrate or nitrite.  In fact, BOILING the water could make things worse.   If you are using a private well, it may be possible to modify the well construction or drill a new well.

Hydroviv Custom Point-of-Use Treatment System

Crystal Quest - Under-the-Counter Point-of-Use Water Treatment System (Specialty Filter) to Reduce Nitrate

Aquasana Reverse Osmosis with Claryum Filtration

US Water Systems – Point-of-Use Reverse Osmosis Unit Recommend adding the High Pressure Pump to Reduce Water Waste and American Made Tank  (Nitrate Reduction 89%+)

US Water Systems – Matrixx Nitrate Water Treatment and Removal System