Department of
Environmental Quality

A variance is a temporary relaxation of water quality standards. Variances are granted by DEQ to facilities for specified pollutants in their wastewater based upon a rationale as to why more time is needed to meet the prevailing criteria. The allowed reasons for a variance are the same as for beneficial use changes under a use attainablity analysis.

Variances generally last for the duration of a federally issued NPDES permit, usually five years, and may be renewed if reasonable progress toward meeting prevailing criteria has been made. Because variances are temporary, Idaho's process is administrative. The rules governing DEQ's granting of variances can be found in Section 260 of Idaho's Water Quality Standards (IDAPA 58.01.02.260). (A narrative description of variance procedures is under development.)

Current Variances from Idaho Water Quality Standards

• Justification for Granting of Variances from the Idaho Water Quality Standards to the Cities of Page, Mullan and Smelterville for the Discharge of Metals from their Wastewater Treatement Plant (May 2009)