Department of
Environmental Quality

Ground water is vulnerable to contamination. Once ground water becomes contaminated, it is very difficult to clean up. Because ground water often moves very slowly, the contamination may exist for a very long time. The contamination may impair ground water for use as drinking water and other beneficial uses and may affect the quality of the surface waters where it discharges.

DEQ is responsible for protecting the quality of ground water in Idaho, but does not undertake this task alone. DEQ monitors and protects ground water in Idaho through partnerships with the Idaho Department of Agriculture (SDA), Idaho Department of Water Resources (IDWR), and many other state, local, and private agencies, organizations, businesses, and individuals. The roles of DEQ, ISDA, IDWR, the Idaho Soil Conservation Commission, and the Idaho Public Health Districts are delineated in the Idaho Ground Water Protection Interagency Cooperative Agreement.

Monitoring Activities

The Idaho Statewide Ground Water Quality Monitoring Program is designed to assess the current condition of Idaho's ground water quality, identify potential problem areas, and detect trends in ground water quality. The program is a cooperative effort between IDWR and the U.S. Geological Survey's Water Resources Division.

DEQ conducts regional and local ground water quality monitoring when the statewide program or other government agencies detect potential problem areas. DEQ also initiates its own evaluations and conducts regional and local monitoring in conjunction with other agencies. DEQ chairs the Idaho Ground Water Monitoring Technical Committee that includes membership from other Idaho state agencies, Public Health Districts, the Idaho Water Research Institute, Idaho's universities, and federal agencies.

Idaho's ground water quality monitoring program results show that significant levels of ground water degradation have occurred in specific areas across the state. This negatively impacts water quality and potentially threatens domestic water supplies, aquaculture, agriculture, mining, industrial, and other ground water beneficial uses. With input from other agencies, DEQ has established a statewide priority list of areas of significantly degraded ground water. This list is based on levels of nitrate and is used to prioritize the development and implementation of management strategies to improve ground water in specific degraded areas.

In addition to the statewide monitoring program and DEQ's ground water monitoring program, the Idaho State Department of Agriculture addresses ground water issues that involve pesticides, fertilizers, animal waste, and other potential agricultural contaminants. The agency conducts regional and local agricultural ground water quality monitoring.

Managed Recharge

Managed recharge occurs when surface water or treated wastewater is intentionally added to an aquifer or the zone of saturation below the water table either through injection wells or by applying water to the land surface (land application), allowing the water to infiltrate down. Learn more.

Mining Point of Compliance Determinations

Because of the nature of mining activities, which involve the extraction of minerals above and within ground water, mining has the potential to impact ground water quality. The state's policy is to protect ground water while allowing mining activities to take place. Learn more.