• The U.S. Environmental Protection Agency (EPA) Region 9 published a new rule requiring privately-owned commercial, industrial, and institutional (CII) sites with five or more acres of impermeable surfaces that discharge into the Los Cerritos Channel/Alamitos Bay and Dominguez Channel and Los Angeles/Long Beach Inner Harbor watersheds to obtain a National Pollutant Discharge Elimination System (NPDES) permit.
• Region 9’s rule follows Region 1’s proposed rule and draft General Permit regulating stormwater discharge for CII properties with one or more acres of impervious surface across three watersheds in Massachusetts.
• EPA using its residual designation authority to regulate additional stormwater discharges may create a roadmap for EPA expanding NPDES permitting requirements to CII sites in other watersheds in California and the United States.

On November 20, 2024, the EPA Region 9 published in the Federal Register its Final Designation of stormwater discharges requiring privately-owned CII sites consisting of five or more acres of impermeable surfaces that discharge into the Los Cerritos Channel/Alamitos Bay and Dominguez Channel and Los Angeles/Long Beach Inner Harbor watersheds¹ to obtain a NPDES permit. The rule is a purported exercise of the EPA’s “residual designation authority” under section 402(p)(2)(E) of the Clean Water Act.

EPA estimates that about 600 facilities fall within the purview of this rule, including, but not limited to:

• Shopping centers
• Auto dealerships
• Hotels/motels
• Distribution centers
• Warehouses
• Office complexes
• Supermarkets
• Parking lots
• Racetracks
• Stadiums
• Greenhouses
• Refineries
• Manufacturers
• Power plants
• Scrap and waste material facilities
• Private schools
• Churches
• Hospitals
• Nursing homes
• Cemeteries

The Final Designation differs from the preliminary designation issued November 2, 2023, in that the EPA is not designating privately-owned facilities at the Ports of Long Beach and Los Angeles.

The EPA’s rule responds to two 2015 petitions requesting action and a federal court order in Los Angeles Waterkeeper v. Pruitt, 320 F. Supp. 3d 1115 (C.D. Cal. 2018), which found that EPA violated the Clean Water Act by declining to regulate stormwater discharges from CII sites in the region. The order requires that the EPA prohibit or issue NPDES permits for discharges of stormwater from privately-owed CII sites like malls, office buildings, and parking lots.

The Los Angeles Regional Water Quality Control Board is working in tandem with the EPA to expand stormwater regulation in the region. The Regional Board prepared an initial draft and took public comment on a proposed General Permit for CII properties in 2022, and published a revised version earlier this year. The Regional Board is expected to finalize the CII General Permit soon. Once finalized, affected dischargers can apply for an NPDES permit by filing a Notice of Intent, providing the necessary discharge information, and paying the application fee.

The new rule follows EPA Region 1’s Proposed Designation and draft General Permit regulating stormwater discharges—also on the basis of residual designation authority—for CII properties with one or more acres of impervious surface across three watersheds in Massachusetts. Unlike Region 1’s proposed action, Region 9’s final rule is narrower in scope both geographically and with regards to the number of properties impacted.

The EPA using its residual designation authority to regulate additional stormwater discharges is unique and may create a roadmap for the EPA expanding its NPDES permitting requirements to other CII sites across California and the country.

If you have any questions or concerns about how the CII Rule affects you, please contact our Water Law attorneys.

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¹ Affected properties will have the following use classification codes with Los Angeles County: 1000 through 2900, 3000 through 3920, 6000 through 6910, 7000 through 7710, and 8100 through 8400.