Nitrate Contamination Potential in Arizona Groundwater: Implications for Drinking Water Wells

Arizona's arid environment and aquifer types allow for the persistence of nitrate contamination in ground water. Agricultural practices and the prevalence of septic systems contributes to this water quality concern, resulting in nitrate exceeding the EPA Maximum Contaminant Level (MCL) in several locations across the state. Working with known nitrate concentrations in 6,800 wells across the state, this fact sheet presents maps showing the probability of nitrate contamination of ground water exceeding the MCL. The importance of monitoring your domestic water supply well for nitrate is emphasized.