Nitrate in Private Water Supplies

High levels of nitrates in private drinking water supplies can pose a health risk to people. Here’s what you need to know if you have a private well that supplies drinking water to your home:

  • A nitrate concentration in excess of 10 mg nitrate per litre indicates water contamination from an organic material. Nitrate may come from water that may be contaminated with material from septic tanks, animal manure, and agricultural fertilizers.
  • People who are exposed to high levels of nitrates over a long period of time may experience health risks. In the body, nitrates are converted into nitrites. Nitrites are identified as a possible cancer precursor. Children under 6 months of age are at particular risk of developing a condition known as methaemoglobinaemia (blue baby syndrome).
  • Private well owners/users should meet the Ontario Drinking Water Objectives of a maximum acceptable concentration of 10 mg nitrate per litre.
  • Private water supplies with high nitrate levels may have the concentration of nitrate in their water lowered through investigation and correction of the problem or through the use of a distiller or an alternative source of water. Please consult a private laboratory for water testing.
  • Levels above the Ontario Drinking Water Objectives of 10 mg nitrate per litre have been found in private well waters in Cambridge Forest Estates, Fournier, Limoges, St. Raphaels, Curran, and Marionville.

For more information, call the Eastern Ontario Health Unit at 613-933-1375 or 1-800-267-7120.