District MS4 Storm Sewer Outfalls. The dataset contains locations and attributes of the MS4 outfalls created as part of the Federal MS4 Permit. GPS outfall locations were captured by DC Water, then DC WASA in 2004-2006. A database provided by WASA identified outfalls, drainage structures, and MS4 outfall locations. The data was verified in conjunctionbetween DOEE and DCWater.