Groundwater Quality in Arizona: A 15-Year Overview of the ADEQ Ambient Monitoring Program (1995-2009)

In pursuing its mandated mission to characterize groundwater quality in the state, the Arizona Department of Environmental Quality has collected samples from 1,477 sites over a 15-year period between 1995 and 2009. The sample sites consisted mainly of domestic, stock, irrigation and municipal wells and, to a lesser extent, springs used predominantly for watering stock and wildlife. Sampling activity was conducted within 35 of the state’s 51 officially designated groundwater basins and covered much of Arizona with the exception of Native American tribal lands. The data provide comprehensive and reliable information on the occurrence and concentrations of groundwater contaminants. This is critical knowledge for the estimated 100,000 private domestic wells in the state whose owners represent about 5 percent of Arizona’s population.