FAQ: What is EPA’s Residual Designation Authority?
EPA can use its “residual designation” authority under 40 CFR 122.26(a)(9)(i)(C) and (D) to require NPDES permits for stormwater discharges or other category of discharges on a case-by-case basis when it determines that:
- the discharges contribute to a violation of water quality standards,,
- are a significant contributor of pollutant to federally protected surface waters, or
- controls are needed for the discharge based on wasteload allocations that are part of “total maximum daily loads” (TMDLs) that address the pollutant(s) of concern.