[NEW] 2025 Technical Guidance Manual Released May 12, 2025 

The Technical Guidance Manual for Stormwater Quality Control Measures (2025 TGM) provides guidance for the implementation of stormwater management control measures in new development and redevelopment projects located in the County of Ventura and the incorporated cities therein. These guidelines have been developed to meet the Planning and Land Development requirements contained in the regional Phase I Municipal Separate Storm Sewer System (MS4) National Pollutant Discharge Elimination System (NPDES) Permit for stormwater and non-stormwater discharges from the MS4 within the coastal watersheds of Los Angeles and Ventura Counties (CAS004004, Order No. R4-2021-0105, (2021 MS4 Permit)).

[NEW] Watershed Management Program Approved May 12, 2025 

On May 12, 2025, the Los Angeles Regional Water Quality Board issued an approval letter of the Ventura Countywide Stormwater Quality Management Program Group’s Watershed Management Program (WMP). The approval letter clarifies compliance metrics for Water Body-Pollutant Combinations and specifies additional requirements including requirements for the adaptive management process. The Minimum Control Measures as defined in the 2021 Regional MS4 Permit became effective with the approval of the WMP (May 12, 2025).

[NEW] Coordinated Integrated Monitoring Program Approved May 12, 2025 

On May 12, 2025, the Los Angeles Regional Water Quality Board issued an approval letter of the Ventura Countywide Stormwater Quality Management Program Group’s Coordinated Integrated Monitoring Program (CIMP). Per the 2021 Regional MS4 Permit, monitoring under the approved CIMP shall be implemented within 90 days of May 12, 2025, or August 10, 2025.

Regional MS4 Permit Adopted July 23, 2021 

The Los Angeles Regional Water Quality Control Board adopted the Regional Phase I Municipal Separate Storm Sewer System (MS4) National Pollutant Discharge Elimination System (NPDES) Permit, Order No. R4-2021-0105 (Permit), on July 23, 2021 and it became effective on September 11, 2021. The Permit applies to Ventura and Los Angeles Counties and all incorporated cities therein, and supersedes the three Orders that previously covered the area, R4-2010-0108 (Ventura County), R4-2012-0175 (L.A. County except for the City of Long Beach), and R4-2014-0024 (City of Long Beach).

2023-24 Annual Report 

Every year the cities and County of Ventura report on Permit compliance and their extensive efforts to improve water quality. Check out our 2024 Annual Report for reporting for the 2023-24 water year, including information about water quality in our beaches and streams, new and updated resources we have developed, and projects we've undertaken.