Nitrate and Nitrite are inorganic ions regulated under the Chemical Contaminant Rules (also known as the Phase II/IV Rules). They are the only acute inorganic contaminants regulated under this rule. All community water systems and non-transient non-community water systems, which have their own source, must comply with the nitrate and nitrite requirements.

Stacey Herreid

Rule Manager

P: 701-328-5287

Fact Sheet


  • What is the maximum contaminant level (MCL) and maximum contaminant level goal (MCLG) for nitrate and nitrite?
    • For nitrate the MCL and MCLG have both been set at 10 mg/L or 10 ppm. The MCL and MCLG for nitrite have both been set at 1 mg/L or 1 ppm.
  • Why are nitrate and nitrite considered acute inorganic contaminants?
    • Nitrate and nitrite are considered acute contaminants due to the potential for sudden and severe onset of health effects.
      Nitrates and nitrites are nitrogen-oxygen chemical units which combine with various organic and inorganic compounds. Once taken into the body, nitrates are converted into nitrites. High levels of nitrate and nitrite are most serious for infants.
      The conversion of nitrate to nitrite by the body can interfere with the oxygen-carrying capacity of a child’s blood, sometimes called Blue Baby Syndrome. This acute condition can occur rapidly over a period of days. Symptoms include shortness of breath and blueness of the skin.
  • What are the possible sources of nitrate contamination in drinking water?
    • Nitrate in drinking water can come from natural, industrial, or agricultural sources. This includes septic systems and run-off from fertilizers or feedlots. Levels of nitrate in drinking water can vary throughout the year. Due to its high solubility and weak retention by the soil, nitrates are very mobile in soil and have a high potential to migrate to ground water.
  • I have already collected the one annual sample for nitrate and nitrite for my water system and it was below the 5 mg/L which would require quarterly testing so why am I being asked to collect another sample?
    • Water systems which have a result of combined nitrate and nitrite above 0.5 mg/L and have not previously collected a sample to be analyzed for individual nitrate and nitrite levels must collect a sample to have the individual analysis performed. This analysis is only run on specific days at the NDDEQ Division of Chemistry Laboratory and therefore, a specific date will be provided to each water system to collect this test if it is required.