California’s New CII Stormwater Permit Expands Compliance Beyond Traditional Industrial Sites in the LA Region

• Many commercial and institutional properties with five or more acres of impervious surface may now require stormwater permit coverage for the first time
• Regulated facilities must register through SMARTS, prepare a Storm Water Pollution Prevention Plan (SWPPP) and select one of three compliance pathways
• Organizations should begin evaluating applicability now, as implementation guidance and permit deadlines continue to develop

In July 2026, the Los Angeles Regional Water Quality Control Board approved the Commercial, Industrial and Institutional (CII) Stormwater Permit. The permit regulates stormwater discharges from commercial, industrial and institutional sites within the Dominguez Channel/Greater Los Angeles and Long Beach Harbor Watershed and the Los Cerritos Channel/Alamitos Bay Watershed.

The permit significantly expands stormwater regulation beyond facilities traditionally covered under the Industrial General Permit. Properties that may now fall under the new requirements include shopping centers, warehouses, distribution centers, office parks, hospitals, private schools and car dealerships.

Of the CII sites with five or more acres within the watersheds, the following are regulated under this permit:

• Sites with five or more acres of impervious area without an NPDES Stormwater permit
• Sites covered by a No Exposure Certification (NEC)
• Sites where only a portion of the facility is covered by a Notice of Non-Applicability (NONA)

For many property owners, this will be their first experience managing a comprehensive stormwater permitting program.

Use this map tool to determine if your site is within the designated watersheds:

Regulated facilities must submit a Notice of Intent (NOI) through California’s Stormwater Multiple Application and Report Tracking System (SMARTS). The NOI must include:

• A facility-specific Storm Water Pollution Prevention Plan (SWPPP)
• Initial stormwater sampling results
• Documentation supporting the selected compliance option

The SWPPP must identify the facility’s Pollution Prevention Team, Best Management Practices (BMPs), site maps and other facility-specific controls.

Initial monitoring also requires analytical testing for a broad range of water quality parameters, including nutrients, bacteria, oil and grease, pesticides, polycyclic aromatic hydrocarbons (PAHs), suspended solids, pH, temperature and metals such as zinc and copper.

Facilities must select one of three compliance options based on their operational strategy and site conditions.

Each pathway carries different operational, capital and long-term management considerations. Selecting the right approach will require careful evaluation of site constraints, compliance costs and business objectives.

The permit’s effective date is October 31, 2026. Existing facilities will be required to:

• Submit a complete NOI and SWPPP within 12 months of the permit’s effective date
• Submit initial sampling results within 18 months
• Submit Compliance Option documentation within six months after all compliance options become available

Organizations should not wait until the effective date to evaluate applicability, identify potential compliance gaps and budget for implementation.

The CII Permit represents one of the most significant expansions of stormwater regulation in California in years. It also establishes a framework that could influence future permits throughout the state.

Property owners, developers and facility managers should begin assessing affected properties, reviewing existing stormwater management practices and determining which compliance pathway best aligns with their facilities. Organizations that prepare early will be better positioned to manage costs, reduce implementation risk and meet future regulatory deadlines.