Nitrate is one of the most common groundwater contaminants in rural areas. It occurs naturally in soil and water as a result of decaying plants and animal residues. Other common sources of nitrate include human sewage and livestock manure. Nitrate is also a common constituent of chemical fertilizers.

Nitrate is highly soluble and readily moves with water through the soil profile. In areas of excess rainfall or over-irrigation, nitrate will be leached below the plant’s root zone and may eventually reach the groundwater. Nitrate in ground water can be derived from natural sources or from point sources, such as sewage disposal systems and livestock facilities. Surface water runoff from fertilized farmland and animal feedlots is a major potential source of nitrate contamination.

Nitrate occurs naturally in groundwater, usually at concentrations far below a level of concern for drinking water safety. However, nitrate in water is not easily noticed since it is colourless, odourless and tasteless. Only water testing can determine nitrate concentration in your drinking water supply. Activities, such as livestock operations or sewage disposal sites located near water supply sources, can potentially contaminate water supplies. Areas with heavy chemical fertilizer use may also result in an elevated nitrate in water supplies. High levels of nitrate are often found to be associated with unacceptable bacteriological water quality, since human sewage and animal manure are significant sources of both nitrate and coliform bacteria. It must be emphasized, however, that drinking water with low nitrate may be unacceptable in terms of bacteriological quality, and vice versa. It is recommended that drinking water supplies should be checked at least once a year, to ensure that a significant increase in nitrate is not occurring.

Nitrate can be removed from water by distillation or reverse osmosis filtration. Some ion-exchange processes have also been found to successfully remove significant quantities of nitrate. However, boiling water will NOT decrease the nitrate concentration in the water. Blending water that has high nitrate levels with the one that has lower concentrations is also a common practice to reduce nitrate in drinking water.

The Saskatchewan Drinking Water Quality Standards and Objectives has established a maximum acceptable concentration (MAC) of 45 mg/L of nitrate (or 10 mg/L of nitrate-nitrogen).

The water lab at the Saskatchewan Disease Control Laboratory can determine how much nitrate is present in a water supply.