Water Quality

​The Department of Environmental Quality is developing rules that will establish a variance for methylmercury in the Willamette Basin. The variance proposes a temporary change in the water quality standard because the current standard is not achievable due to global sources of pollution.

Wastewater dischargers in the Willamette Basin with a National Pollutant Discharge Elimination System permit will be able to apply for a variance under the rules.

Levels of mercury in Willamette Basin fish are higher than the water quality standard, primarily due to the deposition of global atmospheric mercury and high levels of mercury in Oregon’s native volcanic soil.

Dischargers who receive coverage under the variance will be required to develop and implement a plan to reduce mercury before it reaches the treatment plant, while still treating to the lowest levels they can achieve. To maintain coverage, they must show progress in reducing mercury. 


Current rulemaking schedule

Advisory committee meetings Nov. 2018 - Aug. 2019:
Public notice period: Sept. 16 – Nov. 4, 2019
Public hearings: Oct. 22 2019
EQC action: January 2020
For additional information on the rulemaking and advisory committee meetings, please visit the DEQ's Willamette Valley Mercury Variance Rulemaking page.


Keep up-to-date

green envelopeStay informed about the mercury variance rulemaking by signing up here to receive email updates. DEQ will add new information about the rulemaking to this webpage as it becomes available.


For more information about this rulemaking contact Aron Borok by email or phone at 503-229-5050 or Debra Sturdevant by email or phone at 503-229-6691 (toll-free at 800-452-4011).