Nitrate is a compound of nitrogen and oxygen found in many food items in your every day diet. Generally, the concentration in ground water is low. Although low levels of nitrate occur naturally in water, higher levels, which are potentially dangerous to some infants, are sometimes discovered.

Wisconsin has adopted a drinking water standard of 10 milligrams per liter (10 mg/l) for nitrate. This standard is mandatory for public water supplies and is used as a guide for private water supplies.

It is often difficult to pinpoint sources of nitrate because there are so many possibilities. Sources of nitrogen and nitrate may include runoff or seepage from fertilized agricultural lands, municipal and industrial waste-water, refuse dumps, animal feed lots, septic tanks, urban drainage and decaying plant debris. The geologic formations and directions of ground water flow influence the possibilities of nitrate contamination from a particular source.

Since 1945, health officials have known that high nitrate levels in drinking water pose a risk to some infants. Their concern is that high nitrate concentrations may cause methemoglobinemia or "blue babies". If an infant is affected, the skin becomes blue, similar to the color of the blood vessels located close to the skin. If this condition is observed, seek medical help immediately.

When water with nitrate exceeding 10 mg/l has been discovered, a number of important points should be remembered:

  • Do not give the water to infants under six months of age, either directly or in formula. Use only safe water from a known low nitrate source.
  • Do not boil high nitrate water to reduce the nitrate level. Boiling actually increases the nitrate level due to evaporation of the water.
  • Seek medical help if the skin of an infant takes on a "blue" tone or tint.

Federal law requires the testing of public water systems, but a high nitrate level can occur in any well. If infants will be consuming water from a private well, an inexpensive water test for nitrate should be requested, in addition to a normal bacteriological test.

You can obtain a water testing kit from the Polk County Health Department office. Call 715-485-8400 for further information.

Links for more Information on Nitrate

Nitrate in Drinking Water