Residual Designation Authority to Address Stormwater Quality Problems in EPA's Pacific Southwest (Region 9)

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) (PDF) 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.

Water Quality Challenges in two Los Angeles Watersheds - Los Cerritos Channel/Alamitos Bay and Dominquez Channel/Los Angeles/Long Beach Harbor

In response to petitions and a 2018 District Court order, Region 9 is considering the use of its residual designation authority to add requirements for certain stormwater sources (based on land use categories) that discharge to these two waterbodies. The proposed designation is specifically for privately-owned commercial, industrial and institutional (CII) facilities to obtain NPDES permit coverage for stormwater runoff only in these two watersheds. Both watersheds are impaired due to elevated levels of copper and zinc and Total Maximum Daily Loads have been established to define needed reductions of these pollutants to restore water quality and beneficial uses of the watersheds.

Region 9 is partnering with the Los Angeles Regional Water Quality Control Board, who is considering the issuance of a new NPDES permit to provide coverage for all CII facilities in these watersheds designated by EPA’s action.

EPA is proposing action under the Clean Water Act (CWA) to designate stormwater discharges from certain privately-owned commercial, industrial and institutional (CII) sites, exclusively within two Los Angeles County watersheds, that are contributing pollutants to impaired surface waters. Once designated, these sites will be required to obtain coverage under a National Pollutant Discharge Elimination System (NPDES) permit.

Documents

EPA’s 2023 Revised Preliminary Designation Memo

• EPA 2023 Preliminary Designation Memorandum: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (pdf) (1.22 MB, October 2, 2023)
  EPA’s Revised Preliminary Designation Memorandum of Certain Commercial, Industrial, and Institutional Stormwater Discharges in the Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles.
• EPA Fact Sheet: Proposed Action to Address Stormwater Pollution in Two Los Angeles Watersheds (pdf) (687.25 KB, November 29, 2023)
  Fact Sheet with information about EPA and the Los Angeles Regional Water Quality Control Board action to reduce the discharge of pollutants in stormwater runoff in two watersheds–the Dominguez Channel/Greater Los Angeles and Long Beach Inner Harbor Watershed and the Los Cerritos Channel/Alamitos Bay Watershed.
• Hoja informativa de la epa: acción propuesta para abordar la contaminación por aguas pluviales en dos cuencas hidrográficas de los ángeles (pdf) (499.51 KB, 29 de noviembre de 2023)
  Hoja informativa con información de la EPA y la Junta Regional de Control de la Calidad del Agua de Los Ángeles están tomando medidas para reducir la descarga de contaminantes en la escorrentía de las aguas pluviales en dos cuencas hidrográficas: la cuenca hidrográfica del Canal Dominguez/puerto interior de Greater Los Angeles y Long Beach, y la cuenca hidrográfica del Canal Los Cerritos/Alamitos Bay.
• Memorandum to File: LA RDA Ports Airports Pollutant Loading Comparison (pdf) (197.88 KB, October 31, 2023)
  Memorandum to file with information about the loading comparison of ports versus airports in two watersheds–the Dominguez Channel/Greater Los Angeles and Long Beach Inner Harbor Watershed and the Los Cerritos Channel/Alamitos Bay Watershed.

EPA’s 2022 Preliminary Designation Memo

• Modeling Data Used for EPA's Analysis: Proposed Action to Address Stormwater Pollution in Two Los Angeles Watersheds (zip)
  Modeling data used in the Preliminary Designation of Certain Commercial, Industrial, and Institutional Stormwater Discharges in the Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County.
• EPA Fact Sheet: Proposed Action to Address Stormwater Pollution in Two Los Angeles Watersheds (pdf) (452.88 KB, July 26, 2022)
  Fact Sheet with information about EPA and the Los Angeles Regional Water Quality Control Board action to reduce the discharge of pollutants in stormwater runoff in two watersheds–the Dominguez Channel/Greater Los Angeles and Long Beach Inner Harbor Watershed and the Los Cerritos Channel/Alamitos Bay Watershed.
• Hoja informativa de la epa: acción propuesta para abordar la contaminación por aguas pluviales en dos cuencas hidrográficas de los ángeles (pdf) (717.28 KB, 1 de septiembre de 2022)
  Hoja informativa con información de la EPA y la Junta Regional de Control de la Calidad del Agua de Los Ángeles están tomando medidas para reducir la descarga de contaminantes en la escorrentía de las aguas pluviales en dos cuencas hidrográficas: la cuenca hidrográfica del Canal Dominguez/puerto interior de Greater Los Angeles y Long Beach, y la cuenca hidrográfica del Canal Los Cerritos/Alamitos Bay.
• EPA 2022 Preliminary Designation Memorandum: Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County (pdf) (520.72 KB, July 15, 2022)
  Request for Preliminary Designation of Certain Commercial, Industrial, and Institutional Stormwater Discharges in the Alamitos Bay/Los Cerritos Channel Watershed and the Dominguez Channel and Los Angeles/Long Beach Inner Harbor Watershed in Los Angeles County.

December 2021 Stakeholder Meetings

On December 6 and 17, 2021, EPA and LA Water Board hosted stakeholder meetings to provide information and solicit feedback and comments on the proposed designation and permit. Both meetings covered the same information. See presentation materials below.

• RDA-CII Stakeholder Meeting Invitation Letter (pdf) (312.31 KB, November 16, 2021)
  Letter from Los Angeles Regional Water Quality Control Board owners/operators of commercial, industrial, and institutional facilities in two specific Los Angeles County watersheds announcing a meeting concerning stormwater runoff regulations that may affect facilities.
• EPA Stakeholder Meeting Presentation (pdf) (3.1 MB, December 2021)
  EPA’s Presentation from the December 2021 Stakeholder Meetings.

August 2022 Public Workshop

On August 30, 2022, EPA and LA Water Board hosted a public workshop to provide information and solicit comments on the proposed designation and permit.  See presentation materials below.

• RDA-CII Public Workshop Presentation (pdf) (2.26 MB, August 2022)
  EPA’s presentation from the August 30, 2022 public workshop.
• Visit the Los Angeles Regional Water Quality Control Board website to access the workshop recording.