Idaho Water Quality: Antidegredation

The Clean Water Act requires every state to adopt Antidegradation Rules to ensure water quality is maintained and not degraded by new discharges of pollution. A key component of each state’s Antidegradation Rules is to prohibit new pollution discharges into the state’s “high quality” lakes, rivers, and streams unless the state determines, after thorough analysis with public involvement, that lowering water quality is “necessary to accommodate important social or economic development.”

In recent years, the Idaho Department of Environmental Quality (DEQ) has taken steps to adopt long overdue Antidegradation Rules. But Idaho’s new Antidegradation Rules contain a gaping loophole, which allows DEQ to exempt any new pollution discharges from these rules if DEQ deems the discharge to be “short-term” or “temporary.” DEQ is regularly using this exemption to approve new pollution discharges to high quality waters throughout Idaho without undertaking the required socioeconomic analysis and without making the required necessity determination.

EPA can allow states to exempt de minimus discharges from their Antidegradation Rules, but only if EPA evaluates the exemption and concludes that the exempted discharges will only have very minor impacts to water quality. EPA, however, approved Idaho’s Antidegradation Rule without even evaluating the impacts of DEQ’s short-term exemption.

December 8, 2014 — We sent EPA a 60-day notice of intent to sue under the Clean Water Act for illegally approving Idaho’s short-term exemption.