Los Angeles Regional Water Quality Control Board Adopts CII Stormwater Permit

On July 23, 2026, the Los Angeles Regional Water Quality Control Board adopted the long-awaited Commercial, Industrial, and Institutional (CII) Stormwater Permit. The adopted permit represents a significant milestone in stormwater regulation and is expected to serve as a model for similar permitting efforts throughout California. It establishes new stormwater management requirements for commercial, industrial, and institutional properties with five (5) or more acres of impervious surface located within the Dominguez Channel/Los Angeles and Long Beach Inner Harbor Watershed and the Los Cerritos Channel/Alamitos Bay Watershed.

The public hearing included presentations from Regional Board staff, comments from stakeholders, environmental organizations, consultants, businesses, and community members. The Board adopted the permit with the revisions that staff presented during the hearing. Board staff also stated that they intend to conduct additional outreach to affected permittees and provide guidance on permit enrollment and implementation following permit adoption. A GIS tool will be added to Stormwater Multiple Application and Report Tracking System (SMARTS) after permit adoption to enable properties to determine permit applicability. The Board further directed staff to continue engaging with Watershed Management Groups (WMGs) and report on their progress within 2.5 years during the implementation period.

The adopted CII Permit provides three compliance options, and each permittee will be required to select the pathway that best aligns with its site and compliance strategy:

1. Regional Project Funding: entering into an agreement with a local Watershed Management Group to fund a regional stormwater project,

2. Specific Design Standard: implementing a property-specific design standard to reduce stormwater runoff, or

3. Direct Demonstration: directly demonstrating compliance with water quality-based effluent limitations.

Based on the State Water Board's cost analysis in the Fact Sheet, Compliance Option 1 is expected to be the most widely selected because it represents the lowest-cost compliance pathway for most permittees.

While the compliance options differ in how permittees ultimately demonstrate compliance, the permit establishes several baseline requirements that apply to all permittees following the permit's effective date (expected soon, now that the permit has been adopted). Key implementation deadlines include submitting the required Permit Registration Documents (PRDs) within 12 months of the permit’s effective date and completing the required initial stormwater sampling within 18 months. Baseline requirements include:   

• Developing and implementing a Stormwater Pollution Prevention Plan (SWPPP);

• Implementing minimum best management practices (BMPs);

• Completing the required initial stormwater sampling;

• Conducting routine inspections; and

• Fulfilling applicable reporting and recordkeeping requirements. 

The selected compliance option determines how a permittee ultimately demonstrates compliance with the permit, but it does not eliminate these foundational stormwater management obligations.

What Changed During the Public Hearing?

While the overall framework of the permit remained intact, the Board directed staff to make several important revisions before adoption. Some of the most notable changes include:

• Compliance Option Deadline: One of the most significant revisions was replacing the proposed floating deadline with a firm deadline. Facilities must now submit the required compliance option documentation within 3.5 years of the permit's effective date, providing greater certainty for permittees and Watershed Management Groups (WMGs).

• Sampling Clarifications: The Board revised permit language to clarify sampling requirements, including when sampling should occur during operating hours. Staff also confirmed that initial sampling is intended to provide baseline information for implementation.

• Permit Clarifications: Additional revisions were made to clarify permit applicability, the definition of the discharger regarding campus properties with multiple parcels, funding provisions, and other implementation language raised during the public comment process.

What Does This Mean for Property Owners and Operators?

Facilities that are potentially subject to the CII Permit should begin evaluation of applicable requirements as soon as possible to ensure compliance with the baseline requirements that apply to all facilities.

Businesses should consider:

• Whether their properties are located within the regulated watersheds and are subject to the permit.

• Evaluating which compliance option is most appropriate for their facilities.

• Understanding new sampling, inspection, documentation, and stormwater management requirements.

• Beginning discussions with consultants and, where applicable, Watershed Management Groups if Compliance Option 1 is being considered.

Why This Permit Matters

The CII Permit is unlike traditional stormwater permits as it establishes a watershed-based regulatory framework for thousands of privately owned commercial, industrial, and institutional properties that have not previously been regulated under an NPDES stormwater permit. During the hearing, Board members and staff acknowledged that this permit is the first of its kind and may serve as a model for future CII stormwater permitting efforts throughout California and beyond.  Petitions for Residual Designation, which is the first regulatory step in developing CII permits, have already been filed in other Regional Water Boards throughout California.  As such, we believe this permit will spread to other areas within California in the coming years.

As implementation moves forward, additional guidance, outreach materials, and implementation tools are expected to become available to help permittees understand their obligations and comply with the new requirements.

How Ashworth Leininger Group (ALG) Can Help

ALG is actively tracking implementation of the adopted CII Permit and assisting clients with evaluating applicability, understanding permit obligations, selecting compliance strategies, and preparing for implementation. Contact Elliott Ripley at eripley@algcorp.com to discuss how the adopted CII Permit applies to your property and what actions may be needed to prepare for compliance.