Water Quality Standards adopted by the states include both designated uses and criteria to protect those uses.
Drinking water is one of the uses that can be designated.
States and Tribes describe water quality in terms of a waterbody either fully supporting, threatened, partially supporting, or not supporting the drinking water designated use. This indicator excludes drinking water supplies drawn from ground water sources. Some States did not designate or assess their waters for drinking water use, or they assumed that other uses that they assessed served as surrogates for drinking water use attainment. Drinking water assessments are inconsistent across states. States and Tribes do not have identical water quality standards or identical methods or criteria to assess their waters.