What is the maximum contaminant level (MCL) for nitrate in drinking water?

The maximum contaminant level (MCL) for nitrate in drinking water is established at 10 mg/L. This level is set by regulatory agencies, such as the Environmental Protection Agency (EPA), to protect public health. Nitrate can be harmful, especially to infants, leading to conditions like methemoglobinemia or "blue baby syndrome," which affects the ability of blood to carry oxygen.

Setting the MCL at 10 mg/L is based on a balance between ensuring safe drinking water and the natural occurrence of nitrates in the environment, primarily from agricultural runoff, wastewater, and some natural sources. This standard reflects significant research on the exposure risks associated with consuming elevated nitrate levels in drinking water and the potential health impacts over time. Such regulations are aimed at minimizing risks to human health while considering practical detection and treatment limitations in water systems.