Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Nitrate and Nitrite

Nitrate and nitrite are widespread in the environment. They are naturally produced by the oxidation of nitrogen by microorganisms and, to a lesser extent, by lightning. The maximum acceptable concentration (MAC) for nitrate in drinking water is 45 mg/L. This is equivalent to 10 mg/L measured as nitrate-nitrogen. The MAC for nitrite in drinking water is 3 mg/L. This is equivalent to 1 mg/L measured as nitrite-nitrogen.