Nearly 95 percent of Idahoans rely on groundwater as their source of drinking water. Nationally, groundwater provides about 50 percent of drinking water. Thus, protection of groundwater from contamination by any substance that might cause health problems is a serious concern. In general, recent surveys in Idaho have found very few rural water wells with nitrate levels higher than the National Public Health Service drinking water standard.
Humans ingest nitrate in food and water.
In older children and adults, nitrate is ingested, absorbed from the digestive tract and excreted rapidly in the urine. Healthy human adults can consume fairly large amounts of nitrate with little if any known short-term adverse effects. The health effects of chronic, long-term consumption of high levels of nitrate are uncertain. They are the subject of several current research studies. Infants younger than 6 months are believed to be susceptible to nitrate poisoning.