Surface Water Management (Title 13) | Environment & Sustainability
xi. Solid and food waste handling; and
xii. Non-stormwater discharges authorized by another NPDES or state waste discharge permit; xiii. Discharges from emergency firefighting activities in accordance with Washington State Department of Ecology NPDES permit authorized discharges; xiv. Discharges from potable water sources, including but not limited to water line flushing, hyperchlorinated water line flushing, fire hydrant system flushing, and pipeline hydrostatic test water. Planned discharges shall be dechlorinated to a total residual chlorine concentration of 0.1 ppm or less, pH-adjusted, if necessary, and volumetrically and velocity controlled to prevent resuspension of sediments in the MS4; xv. Discharges from lawn watering and other irrigation runoff. These discharges shall be minimized through water conservation efforts; xvi. Dechlorinated swimming pool, spa and hot tub discharges. The discharges shall be dechlorinated to a total residual chlorine concentration of 0.1 ppm or less, pH-adjusted and deoxygenized if necessary, volumetrically and velocity controlled to prevent resuspension of sediments in the MS4. 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;
xii. Application of pesticides.
d. The following types of non-stormwater discharges shall not be considered prohibited discharges for the purpose of this chapter unless the director determines that the type of discharge, whether standalone or in combination with other discharges, is causing significant contamination of surface and stormwater or groundwater:
i. Diverted stream flows;
ii. Rising groundwaters;
iii. Uncontaminated groundwater that seeps into or otherwise enters stormwater conveyance systems through such means as defective pipes, pipe joints, connections, or manholes;
iv. Uncontaminated pumped groundwater;
v. Foundation drains;
vi. Air conditioning condensation;
vii. Irrigation water from agricultural sources that is commingled with urban stormwater;
viii. Springs;
ix. Uncontaminated water from crawl space pumps;
x. Footing drains;
xvii. Street and sidewalk wash water, water used to control dust, and routine external building
xi. Flows from riparian habitats and wetlands;
Effective | January 1, 2022 Revisions | June 29, 2022
Title 21: Sammamish Development Code | 161
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