Idaho DEQ Water Quality Beneficial Uses / Standards (NHD 100K)

Beneficial Uses A water quality standard defines the water quality goals for a water body or portion thereof, in part by designating the use or uses to be made of the water. The beneficial use of a water body must consider its actual use, the ability of the water to support in the future a use that is not currently supported, and the basic goal of the Clean Water Act that all waters support aquatic life and recreation where attainable. Idaho must designate its uses accordingly. A designated use is a beneficial use assigned to a specific water body in Idaho water quality rules. The Clean Water Act requires Idaho to recognize existing uses, which are uses that are/were actually attained in a water body on or after November 28, 1975, whether or not they are designated uses. In some cases, a water body does not have uses designated. For these water bodies, Idaho applies a presumed use protection, meaning the water body will be protected for cold water aquatic life and contact recreation. Often this presumed use protection is referred to as a presumed use. In designating uses, Idaho considers the use and value of the water body for public water supply; for protection of fish, shellfish, and wildlife; and for recreational, agricultural, industrial, and navigational purposes. While a water body may have competing beneficial uses, federal law requires DEQ to protect the most sensitive of the beneficial uses. Beneficial Uses Home Page Idaho's Water Quality Standards (PDF) Water Quality Standards Home Page Idaho DEQ 2022 Integrated Report Mapping Application EPA Actions on Proposed Standards Idaho DEQ Open Data, GIS HUB