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San Clemente's 24 Hour Pollution Reporting Hotline is (949) 366-1553

Water Quality Requirements for Development Projects

Water quality regulations for Priority Projects may require Low Impact Design (LID) on-site retention and Hydromodification Management measures.  It is crucial that these are considered early in the design process.

The City encourages all applicants to contact Zachary Ponsen, Senior Civil Engineer at (949) 361-6135 or by e-mail at, to discuss the water quality requirements for your project early in the planning phase to ensure that your design will meet applicable requirements.

All development and redevelopment projects, regardless of priority, shall implement the site design and source control principles, where applicable and feasible, to maximize infiltration, provide retention, slow runoff, and reduce pollutants at their sources.

All priority projects shall meet Water Quality Management Plan (WQMP) and Hydromodification Management Plan (HMP) requirements as described in the documents and tools below. The project's WQMP is a plan for minimizing the adverse effects of urbanization on site hydrology, runoff flow rates and pollutant loads. Hydromodification management measures address the changes in the magnitude and frequency of stream flows and associated sediment load due to urbanization or other changes in the watershed land use and hydrology and the resulting impacts on receiving channels, such as erosion, sedimentation and potentially degradation of in-stream habitat.

To determine if your project is a priority project, use the WQMP Checklist Priority Development Project (PDP) Criteria.

Development and Redevelopment projects applying for discretionary and ministerial permits are required to complete the Water Quality Assessment Form and include it as part of the initial permit application. Staff will review the permit application and supporting documents to determine the applicability of the South Orange County model Water Quality Management Plan (WQMP) requirements.

The following updated documents and tools will assist you in preparing an acceptable Water Quality Management Plan (WQMP), including appropriate hydromodification management measures, for your project. Please use these current tools and disregard previous iterations.

 Documents and Tools for WQMP/HMP Preparation:

  • South Orange County Model WQMP, dated September 28, 2017. This document describes the water quality requirements and the process to develop the project's WQMP.
  • Technical Guidance Document, dated September 28, 2017. These documents are the technical resources companion to the Model WQMP and the WQMP Template and is the "how" to meet the requirements in the Model WQMP and how to use the WQMP Template to prepare your project's WQMP. The cover memo highlights the key differences associated with applying the TGD in North versus South Orange County, with guidance, either as footnotes or as text insertions, on key topics that relate to South Orange County criteria. It is important to read and understand this as you begin to develop your project's WQMP. This document is bookmarked and internally linked for easy navigation.
  • Model WQMP Template, dated September 28, 2017 (MS Word). This WQMP template is the framework for preparing your project's WQMP. The use of this template is highly encouraged and will facilitate acceptable preparation and City review and approval of your project's WQMP.
  • Worksheets from the TGD (MS Word). The below worksheets are identical to those contained in the TGD, however they are available in editable MS Word so that they can be created for your project and included in your project's WQMP.

Worksheet 1 - Infiltration Feasibility Categorization

Worksheet 2 - Summary of Groundwater-Related Feasibility Criteria

Worksheet 3 - Factor of Safety and Design Infiltration Rate

Worksheet 4 - Hydrologic Source Control Calculation Form

Worksheet 5 - Simple Design Capture Volume Sizing Method

Worksheet 6 - Capture Efficiency Method for Full Infiltration

Worksheet 7 - Biofiltration Routing Method

Worksheet 8 - Static Volume Method for Sizing Bioretention BMPs

Worksheet 9 - Flow-Based Compact Biofiltration Method

Worksheet 10 - Nomograph Method for Determining Capture Efficiency

Worksheet 11 - Capture Efficiency and Multiplier Method

  • For projects given discretionary approval (i.e. approval by Planning Commission and/or City Council) prior to September 28, 2017, you can use the 2013 WQMP Template, TGD, and Worksheets
  • Hydromodification Management Plan, dated April 1, 2015 and revised on September 28, 2017. This document describes the hydromodification requirements and the process to develop the project's hydromodification management measures, when applicable.

Note: South Orange County has submitted to the San Diego Regional Water Quality Control Board a Watershed Management Area Analysis (WMAA) that proposes additional exemptions to the Hydromodification Management Requirements. Once the WMAA is accepted, the additional exemptions may be effective, however until then, the current exemptions only include:
  1. Existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean; and
  2. Conveyance channels whose bed and bank are concrete lined all the way from the point of discharge to water storage reservoirs, lakes.


To download the South Orange County Hydrology Model (SOCHM) and Guidance Manual, please visit the OC watersheds webpage at: and scroll about half-way down.

Though a work in progress, the Orange County Georesearch tool available at the link above may provide some helpful information to help you develop your project's WQMP and HMP. Click on the link below. Data specific to WQMP and HMP preparation is located in the "OC Watersheds" layer. The County will periodically provide training regarding use of this tool and information will continue to be added when available.

 WQMP Training Opportunities

Please see the following YouTube videos for training opportunities:




Construction - New Development / Significant Redevelopment

palmsThe City’s construction guidelines are designed to prevent pollutant discharges from construction sites and to ensure proper disposal of waste materials. Environmental considerations must be taken on all construction sites, small and large, to prevent the transport of pollutants to the storm drain system and ultimately to the coastal waters of San Clemente. 

Construction sites disturbing one or more acres of soil, or less than one acre but part of a larger common plan of development that in total disturbs one or more acres, are required to obtain coverage under the California General Construction Stormwater Permit and have a Stormwater Pollution Prevention Plan (SWPPP) prepared prior to issuance of city permits.

New development and significant redevelopment standards in San Clemente are modeled after County and State guidance requiring that all new projects include specific post-construction environmental considerations to reduce or eliminate sources of pollutants. Projects defined by regulations to be “priority projects” are further required to prepare a Water Quality Management Plan (WQMP) prior to issuance of city permits. Although the City generally welcomes new development projects, care must be taken to preserve our natural resources for the lasting enjoyment of all San Clemente residents.

The brochure Best Management Practices for Construction Sites has been developed as part of the educational component of the Clean Ocean Program. This brochure details BMPs and guidelines for contractors and field personnel, and is also available in Spanish.

Stormwater Pollution Prevention Plan (SWPPP)

pelicanA Stormwater Pollution Prevention Plan (SWPPP) is required by the San Diego Regional Water Board to detail the specific construction BMPs that will be implemented to reduce or eliminate the migration of pollutants from construction sites to natural water courses or the City’s storm drain system. A SWPPP is considered a “living document” that must be modified frequently through the life of a construction project depending on the progress of construction activities and the appropriateness of selected BMPs. The City does not review or approve the SWPPP.

The State Water Resources Control Board has information on SWPPP and NPDES Construction permit requirements on its website: Click here!



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