• What is a Watershed?

    A watershed is the total land area, including our yards, from which stormwater drains into streams, rivers or other bodies of water.
    Click here to find your watershed.

  • Watershed Protection Tips for Pet Owners

    Check out the brochure at www.cleanwatershed.org.

  • Watershed Protection Tips for Car Owners

    Get tips on how to be a responsible car owner at www.cleanwatershed.org
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News and Announcements

[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.

Quick Links

[NEW] 2025 Technical Guidance Manual

[NEW] 2025 Technical Guidance Manual Tool (downloads Excel file)

2024 Annual Report

2021 Regional Permit

2018 Post Construction Mitigation Requirements Workshop

Post-Wildfire Resources

Ventura Countywide Unified Storm Drain Map

Report of Waste Discharge

Clean Business Fact Sheets

Ventura County Rainfall Map

Articles

Report Illegal Dumping/Discharge

Seen something questionable being dumped in a gutter or storm drain?

Help us keep it from happening again. Click the image to report.

 

 

 

 

Community for a Clean Watershed

How can you help protect the watershed?

The Community for a Clean Watershed website is full of easy, practical tips for residents, businesses, and visitors in Ventura County.

Click the image to find out more.

Ventura Countywide Unified Storm Drain System Map

A Ventura Countywide Unified Storm Drain System Map is now available!

The map was created by mapping natural and engineered drainage system linkages using available topographic information, construction record drawings, and other sources and combining it with existing storm drain data.

What's the big deal about runoff?

Runoff carries pollutants. Water that doesn't soak into the ground becomes runoff. Click here for ten easy tips to help reduce runoff.

How does runoff impact me?

Runoff carries pollutants through our watershed, which can then cause issues for people and wildlife. Find out more.

What role does VCSQMP play?

VCSQMP works to improve runoff quality, monitor watershed health, and comply with the Ventura Countywide Stormwater Permit.

How is our River Water Quality?

River water quality has improved in Ventura County since 2003/04 and is generally good. Click here to find out more.

This page is to communicate information on the revisions to Technical Guidance Manual for Stormwater Control Measures. If you would like to be notified by email when this page is updated, please send a request to This email address is being protected from spambots. You need JavaScript enabled to view it. with "TGM Stakeholder Email" in the subject line.

TGM Errata 2025 Cover Page

[NEW] 2025 TGM
This 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), henceforth referred to in this document as the 2021 MS4 Permit.
► 2025 TGM
► 2025 TGM Tool - An updated electronic tool to assist land development project applicants in meeting the new LID requirements under the new Permit. [To ensure you use the correct version of this tool always check with the agency that has jurisdiction over your project before starting. Links are provided at the bottom of this page.]
2025 TGM BMP Sizing Worksheets:
► Sizing_Worksheet_-_BIO-1_BIO-2.pdf
► Sizing_Worksheet_-_HM-1.pdf
► Sizing_Worksheet_-_HM-2.pdf
► Sizing_Worksheet_-_HM-3.pdf
► Sizing_Worksheet_-_INF-1_INF-2_INF-4.pdf
► Sizing_Worksheet_-_INF-3.pdf
► Sizing_Worksheet_-_INF-5.pdf
► Sizing_Worksheet_-_INF-7.pdf
► Sizing_Worksheet_-_PT-3.pdf
► Sizing_Worksheet_-_PT-4.pdf
► Sizing_Worksheet_-_RWH-1.pdf

TGM Errata Update 2018 Version
The 2015 TGM Errata Update was updated in 2018 to correct minor errors and unintentional omissions. Due to the evolving nature of stormwater quality management, the TGM may continue to be updated to correct errors, to incorporate new and innovative control measures, or to add the Hydromodification Control Plan.
► Errata Update TGM (June 2018)
► 2018 Errata Update Summary
► 2018 TGM Tool - An updated electronic tool to assist land development project applicants in meeting the new LID requirements under the new Permit. [To ensure you use the correct version of this tool always check with the agency that has jurisdiction over your project before starting. Links are provided at the bottom of this page.]

TGM Errata Update 2015 Version
The 2011 TGM was updated in 2015 to correct minor errors and unintentional omissions. Due to the evolving nature of stormwater quality management, the 2011 TGM may continue to be updated to correct errors, to incorporate new and innovative control measures, or to add the Hydromodification Control Plan.
► Errata TGM (May 2015)
► Errata Comments

The Technical Guidance Manual was approved by the Executive Officer of the LA Regional Board on July 13, 2011. The new rules became effective on October 11, 2011. For more information on how the effective date applies to projects see page 1-8 of the TGM.

► Final 2011 Technical Guidance Manual (July 2011)
► An electronic tool to assist land development project applicants in meeting the new LID requirements under the new Permit. [To ensure you use the correct version of this tool always check with the agency that has jurisdiction over your project before starting. Links are provided at the bottom of this page.]
► Ventura Stormwater Permit LID Alternative Compliance Stakeholder Meeting Announcement
► July 13, 2011 Approval Letter from Regional Board

Training Materials from June 21st, 2011, Seminar
►Morning Presentation (June 2011)
►Afternoon Presentation (June 2011)
►Flow Charts (June 2011)

Related Documents
►Final Technical Guidance Manual unapproved (November 2010)
►Transmittal letter to Regional Board (November 2010)
►Summary of comments and changes (November 2010)
►Effective date language (October 2010)
►Comment Letter - Calleguas Municipal Water District (October 2010)
►Comment Letter - City of Ventura (October 2010)
►Comment Letter - Contech (October 2010)
►Comment Letter - Jackson, DeMarco, Tidus & Peckenpaugh (October 2010)
►Comment Letter - Jensen Design (October 2010)
►Comment Letter - Natural Resources Defense Council & Heal the Bay (October 2010)
►Comment Letter - Paul Crabtree (October 2010)
►Comment Letters Summary (October 2010)
►Presentation - Rebecca Winer-Skonovd - TGM Revision, Step-by-Step Process (September 2010)
►Presentation - Lisa Austin - Land Development TGM Revisions (September 2010)
►Ventura County TGM for Stormwater Quality Control Measures (September 2010)
►Ventura County Technical Guidance Manual for Stormwater Quality Control Measures (May 2010)
►Presentation - Meeting Purpose and Objectives (January 2010)
►Presentation - Lisa Austin, Geosytnec Consultants (January 2010)
►Presentation - Rebecca Winer-Skonovd, Larry Walker Associates (January 2010)
►Meeting agenda (January 2010)
►Draft process flow chart (January 2010)
►Draft alternative compliance flow chart (January 2010)
►Draft outline of Technical Guidance Manual (January 2010)

 

Technical Guidance Manual (July 2002) - Applicable only to projects with applications deemed complete prior to the updated rule in 2011.

►Main Report (includes page updates)