Summary

Water quality standards comprise designated uses and water quality criteria. These standards are critical in making accurate, scientifically based determinations about which of the nation's waters are most in need of cleanup. GAO examined the extent to which (1) states are changing designated uses when necessary, (2) EPA is assisting states toward that end, (3) EPA is updating the "criteria documents" states use to develop the pollutant limits needed to measure whether designated uses are being attained, and (4) EPA is assisting states in establishing criteria that can be compared with reasonably obtainable monitoring data.

The extent to which states are changing designated uses varies considerably. Individual states made anywhere from no use changes to over 1,000 use changes during the 5-year period, from 1997 through 2001. Regardless of the number of use changes states made, nearly all states report that some water bodies within their states currently need changes to their designated uses. To do so, many states said they need additional EPA assistance to clarify the circumstances in which use changes are acceptable to EPA and the evidence needed to support those changes. While EPA has developed and published criteria for a wide range of pollutants, the agency has not updated its criteria documents to include sedimentation and other key pollutants that are causing approximately 50 percent of water quality impairments nationwide. In addition to needing new criteria documents, states need assistance from EPA in establishing criteria so that they can be compared with reasonably obtainable monitoring data. Changing either designated uses or criteria is considered a standards modification. Twenty-two states reported that an improvement in the process for changing designated uses would result in different water bodies being slated for cleanup; 22 states also reported that an improvement in the process for modifying criteria would have that effect. Collectively, 30 states would have different water bodies slated for cleanup with an improvement in the process of modifying standards.