Watershed-Based Residual Designation Actions in New England

• EPA's Residual Designation Authority
• EPA's Watershed Based RDA Actions in New England
• More Information

EPA's Residual Designation Authority

The Clean Water Act (CWA) and related regulations define the specific construction, industrial and municipal stormwater sources that must be authorized by an NPDES permit. The CWA also recognizes that other sources may need to be regulated on a case-by-case or category-by-category basis based on additional information or localized conditions. The authority to regulate other sources based on the localized adverse impact of stormwater on water quality through NPDES permits is commonly referred to as the "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 other stormwater discharges or 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.

In addition, designation can be requested by petition.

EPA's Residual Designation Authority webpage contains additional information on EPA's Residual Designation Authority.

EPA's Watershed Based RDA Actions in New England

• Residual Designation in the Charles River Watershed, Mystic River Watershed and Neponset River Watersheds
• Petition to Designate Certain Properties in the Great Bay Estuary Watershed

More information

For additional information contact: R1.RDA@epa.gov