Recently, the United States Congress enacted laws that provide for protection and monitoring of groundwater quality. Many attempts to monitor groundwater quality have shown that such monitoring is usually costly and difficult because groundwater is relatively inaccessible and the chemical behavior of pollutants in the subsurface is very complex. In response, a monitoring methodology has been developed under sponsorship of the U.S. Environmental Protection Agency. This methodology has excellent potential for application at state and local levels of government. The methodology is briefly discussed and the published reports that contain details on it are summarized and referenced.