Water Quality

On January 7, 2015, the Environmental Quality Commission adopted, and on Aug. 4, 2015, the U.S. Environmental Protection Agency approved revisions to Oregon’s ammonia water quality standards for the protection of aquatic life. These criteria are now effective for all Clean Water Act programs in Oregon. EPA’s approval also included a correction to the pH value applicable to the Snake River, and revisions to the West Division Main Canal water quality standards in the Umatilla Basin. 
Revised ammonia criteria  (Table 30) 


The revised ammonia criteria, based on EPA's latest recommendations, protect sensitive freshwater mussels and snails, including other aquatic species. Current information indicates that freshwater mussels and snails are present in many waterbodies across Oregon. The adopted criteria are expressed as Total Ammonia Nitrogen (NH3 and NH4) and continue to be dependent on the pH and temperature of water. 


Contact Debra Sturdevant with the DEQ Water Quality Standards Program for additional information.