Areas of Drilling Concern (ADC) are designated by the Director in response to known occurrences of waste or contamination of the state's water resources and are established to protect public health and the state's water resources.
Any person drilling a new well or deepening/modifying an existing well for any purpose in an area of drilling concern must comply with additional requirements. These additional well drilling and well construction requirements are based on geologic and hydrologic conditions specific to the ADC and are designed to reduce the potential for spreading contamination to other aquifers.
Currently, Idaho has two active ADCs: Bunker Hill and West Boise. Both are the result of groundwater being contaminated by chemicals or heavy metals introduced by industrial and commercial operations.
Idaho Code § 42-238(15) - ADCs can be designated to protect public health and to prevent waste or contamination of ground or surface water.
Active and Proposed ADCs
Reason and Related Documents
20010521May 21, 2001
The West Boise ADC order was signed into effect on May 21, 2001 in response to a request from Vopak USA Inc. and the Idaho Department of Environmental Quality to prevent spreading of a groundwater contaminant plume containing the cleaning agent Perchloroethylene (PERC) above Idaho's groundwater quality standards.
The Bunker Hill ADC order was signed into effect on June 3, 1994 and was the first ADC to be designated by IDWR. The order was in response to a request from the U.S. Environmental Protection Agency, the Idaho Department of Environmental Quality, the Idaho Department of Health and Welfare, and the Panhandle Health District because of concerns for public health in the Bunker Hill Superfund site. Groundwater contamination resulted from leaching of heavy metals from mine tailings and mine processing wastes.
The City of Meridian submitted a petition for the designation of a West Ada ADC (WAADC). The proposed ADC is intended to protect the groundwater resources by preventing the co-mingling of groundwater from different aquifers and sub-aquifers (production zones) which have different groundwater chemistries and hydraulic pressures. The petition for the WAADC provides a detailed report prepared by Hydro Logic, Inc. documenting the hydrogeologic conditions in the Meridian area. The report documents both natural and anthropogenic contamination in the aquifers near Meridian.