Without nitrogen life on this planet would cease. Nitrate is a naturally occurring chemical compound that is formed in the soil when nitrogen and oxygen combine. Small amounts of nitrate are normal but large amounts can severely pollute groundwater and cause severe consequences to life. Sources of nitrogen in the soil are chemical fertilizers, septic system discharge and livestock waste. A portion of chemical fertilizer will convert to nitrate in the soil.
Ammonia is present in the waste of both humans and animals.
It enters the soil from inadequate or poorly managed septic systems. Plants can only absorb so much nitrate from the soil and the excess is then carried down through the soil into the groundwater by the action of rain, snowmelt and irrigation. The process is called leaching. As previously described, the action of leaching transports excess nitrate down through the soil where it eventually enters the groundwater table and then is brought to the surface by your well pump. Wells in sandy soils, shallow wells and improperly constructed wells are more likely to have high nitrate content.