OAR 340-041-0021: pH

(1) Unless otherwise specified in OAR 340-041-0101 through 340-041-0350, pH values (Hydrogen ion concentrations) may not fall outside the following ranges: (a) Marine waters: 7.0-8.5; (b) Estuarine and fresh waters: See basin specific criteria (OAR 340-041-0101 through 340-041-0350). (2) Waters impounded by dams existing on January 1, 1996, which have pHs that exceed the criteria are not in violation of the standard, if the Department determines that the exceedance would not occur without the impoundment and that all practicable measures have been taken to bring the pH in the impounded waters into compliance with the criteria.