NPDES Permit for U.S. General Services Administration Downing Reservoir Groundwater Treatment System in Colorado

Under National Pollutant Discharge Elimination System permit number CO-0035033, the U.S. General Services Administration is authorized to discharge wastewater from its groundwater treatment system located at the Denver Federal Center in Lakewood, Jefferson County, Colorado, to McIntyre Gulch, tributary to Lakewood Gulch, tributary to the South Platte River.

Current Permit

• CO0035033 U.S. General Services Administration Downing Reservoir Groundwater Treatment Facility NPDES Permit (pdf) (285.7 KB, September 1, 2018)
• CO0035033 U.S. General Services Administration Downing Reservoir Groundwater Treatment Facility Statement of Basis (pdf) (2.01 MB, September 1, 2018)

Draft Permit

The EPA accepted public comments on the draft permit through May 19, 2025.

• CO0035033 Downing Reservoir GWTS Draft NPDES Permit (pdf) (684.33 KB, April 17, 2025)
  The draft NPDES discharge permit.
• CO0035033 Downing Reservoir GWTS Draft Statement of Basis (pdf) (1.4 MB, April 17, 2025)
  The statement of basis for the draft NPDES discharge permit.