Model Water Quality Management Plan (WQMP)

The Model Water Quality Management Plan (WQMP) and Technical Guidance Document (TGD) provide guidance for “priority” new development and significant redevelopment projects to comply with the two National Pollutant Discharge Elimination System (NPDES) Phase I Municipal Separate Storm Sewer System (MS4) permits held jointly by the Orange County cities, unincorporated Orange County, and Orange County Flood Control District (collectively, Permittees). 

Where is the proposed project located? 

The following two sections detail program documents developed and managed by the County of Orange, as Principal Permittee, on behalf of the Permittees. Use the web app below to view relevant water quality requirements and guidance for proposed land development projects, given a particular location. Additionally, if your project is located in any of the 34 Orange County cities, please visit that City’s website to view jurisdiction-specific requirements, templates, and checklists. If your project is in unincorporated County, please visit  explore OC Development Services' Water Quality web page. 

North Orange County Project Guidance

In response to permit requirements from the Santa Ana Regional Water Quality Control Board (RWQCB), the following guidance documents have been prepared for proposed projects located in north and central Orange County (above El Toro Road):

• Model WQMP 05.2011 - May 2011  picture_as_pdf
• Technical Guidance Document 12.2013  - December 2013  picture_as_pdf

South Orange County Project Guidance

In response to permit requirements from the San Diego RWQCB, the following guidance documents, collectively equivalent to the “BMP Design Manual”, have been prepared for proposed projects located in south Orange County (below El Toro Road):

• Model WQMP 09.2017  - September 2017 picture_as_pdf
• Technical Guidance Document 12.2013  - September 2017 picture_as_pdf
• Hydromodification Management Plan  - September 2017 picture_as_pdf
• Water Quality Equivalency Guidance Document -  2018 Update picture_as_pdf

A hydrologic model called the south Orange County Hydrology Model (SOCHM) has been developed to assist project proponents in selecting and sizing hydromodification control where applicable.

• SOCHM download   picture_as_pdf
• SOCHM Guidance Manual   picture_as_pdf

Toolbox 

The following tools are available to assist project proponents:

• Contact the Help Desk   explore with questions
• Training Modules
  • North Orange County   explore
  • South Orange County  explore
• OC Environmental Resources GIS Data Portal  explore, which includes the WIHMP Data Map.