Nitrates/Nitrites

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. Nitrates occur in the soil, animal excreta, crop residues, human wastes, some industrial wastes, and nitrogen fertilizers. They are soluble and move with water. Excessive levels of nitrate and nitrite in drinking water can cause serious illness in infants by interfering with the oxygen-carrying capacity of the child’s blood. Symptoms include shortness of breath and blueness of the skin. Nitrates and nitrites also have the potential, after a lifetime of exposure, to cause diuresis, increased starchy deposits, and hemorrhaging of the spleen.

Do the Nitrate/Nitrite regulations apply to my water system?

Yes, all public water supply systems must monitor for nitrates and nitrites in their water supply.

Frequency of Sampling

Nitrate and Nitrite samples are required to be taken at each entry point, the point where the source water enters the distribution system after treatment. Nitrite samples must be taken every 3 years. Nitrate samples in surface water must initially be taken quarterly. After a year of safe samples, surface water systems samples must be taken annually. Ground water systems must sample for nitrate annually. Nitrate levels have been known to fluctuate so yearly monitoring is critical.

If the Maximum Contaminant Level is violated your water system must:

  1. Correct all sanitary survey deficiencies
  2. Provide an alternate source of water
  3. Eliminate the groundwater source of contamination
  4. Install treatment for the contaminated groundwater source
  • Notify the Drinking Water Program and complete Public Notification as required.
  • Take a confirmation sample for nitrate and nitrite within 24 hours.
  • Work with the Drinking Water Program to determine the best way to reduce the level of contaminant in your water supply.  Treatment processes, mixing  the contaminated supply with another supply that does not exceed the Maximum Contaminant Level, or obtaining a new source of water are options to consider.
  • Enter into an agreement with the  Drinking Water Program to allow the water system to continue to use the water supply while the solutions to the Maximum Contaminant Level violation are being explored and any needed financing is being planned.
  • Contact resource agencies listed on the Resource Agencies page of this web site for help in planning and finding financing for your system improvements.
  • Monitor quarterly for at least four quarters.

Contaminant

MCL *(mg/L)

Potential health effects from ingestion of water

Sources of contaminant in drinking water

Nitrate (measured as nitrogen)

10

Infants below the age of six months who drink water containing nitrate in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits

Nitrite (measured as nitrogen)

1

Infants below the age of six months who drink water containing nitrite in excess of the MCL could become seriously ill and, if untreated, may die. Symptoms include shortness of breath and blue-baby syndrome.

Runoff from fertilizer use; leaching from septic tanks, sewage; erosion of natural deposits