A. Nonstormwater discharge permitted under an NPDES permit issued by the Department of Ecology.

B. Potable water, including water from water line flushing, hyperchlorinated water line flushing, fire hydrant system flushing, and pipeline hydrostatic test water. Planned discharges shall be dechlorinated to a concentration of 0.1 ppm or less, pH-adjusted if necessary, and in volumes and velocities controlled to prevent resuspension of sediments in the stormwater system.

C. Dechlorinated Swimming Pool Discharges. These discharges shall be dechlorinated to a concentration of 0.1 ppm or less, pH-adjusted, and reoxygenated if necessary and in volumes and velocities controlled to prevent resuspension of sediments in the stormwater system. Discharges shall be thermally controlled to prevent an increase in temperature of the receiving water. Swimming pool cleaning wastewater and filter backwash shall not be discharged to the MS4.

D. Nonstormwater discharges covered by another NPDES permit, provided, that the discharger is in full compliance with all requirements of the permit, waiver, or order and other applicable laws and regulations; and provided, that written approval has been granted for any discharge to the storm drain system. (Ord. 3023, 4/25/23; Ord. 2568, 7/13/10; Ord. 2539, 11/24/09)