Standards for Nitrates in Drinking Water in California

Under California's Safe Water Drinking Act of 1996, public health agencies in the state set the levels at which nitrates and other substances in drinking water become a health hazard. The standards were put in place to protect vulnerable humans, particularly infants and others whose immune systems are weaker than those of healthy adults.

Nitrate

• The California Office of Environmental Health Hazard Assessment's standard for nitrogen in drinking water is 45 PPM, or parts per million, meaning that for every liter of water, no more than 45 milligrams of nitrate should be present. The standard was adopted by the Office of Environmental Health Hazard Assessment (OEHHA) in 1997 and based on identical standards that were put in place years earlier at the U.S. Environmental Protection Agency and California Department of Health Services.

Nitrate/Nitrite

• California's standard for the nitrate/nitrite combination in water is 10 PPM million. Nitrite and nitrate are similar compounds in that they both consist of a nitrogen atom joined to oxygen atoms; however, nitrate has three oxygen atoms, while nitrite has only two. In nature, nitrates and nitrites are easily converted into one another.

Nitrite-Nitrogen

• The standard for nitrite-nitrogen in water is 1 PPM. This standard, like the others, is based on tests that found that high levels of the nitrates and related chemicals could result in the occurrence of a blood disorder called methemoglobinemia, which is the main adverse health effect caused by nitrate or nitrite exposure.

Nitrate Exposure

• For 99 percent of the adult population in the United States and California, only about 1 to 3 percent of exposure to nitrate and nitrate compounds comes from drinking water, according to the OEHHA. However, the exposure for nursing infants can be significantly greater if they consume the drinking water used to prepare their formula.