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MS4 Permits and Requirements

The San Diego Regional Water Quality Control Board (San Diego Water Board) issues the Phase I Municipal Separate Storm Sewer System (MS4) Permit to 39 municipal, county and special district entities in San Diego, south Orange and Southwestern Riverside Counties (known as Copermittees). This permit regulated what is allowed to leave our storm drain system and enter local waterways. 

Code Enforcement

The MS4 Permit requires that all copermittees develop and enforce stormwater regulations to prohibit pollutants and other illegal discharges from entering the storm drain system.  For more information, please visit our Code Enforcement webpage.  

Stormwater Standards Manual and Related Documents

New Development and Re-Development

The City is required to update its Stormwater Standards Manual to conform to the 2013 MS4 Permit and for consistency with the Regional Model Best Management Practices (BMP) Design Manual.

  • The 2018 Stormwater Standards Manual is located in the Land Developement Manual webpage here

*An update to the Stormwater Standards Manual will be posted in May 2021. The update is focused on clarifications to Priority Development Project determinations regarding routine maintenance activities.  

Offsite Stormwater Alternative Compliance Program for Meeting New Development Requirements

The MS4 Permit provides Offsite Alternative Compliance, as an option for Priority Development Projects in lieu of implementing onsite structural best management practices to comply with pollutant control and hydromodification management requirements. The City will implement the alternative compliance program in two phases:

  • Phase I: Applicant Implemented Alternative Compliance Projects where the project applicant would propose an offsite alternative compliance project and be fully responsible for the project’s design, construction, operation, and long-term maintenance. Phase I implementation coincides with Feb. 16, 2016, the effective date of the Stormwater Standards Manual Update.
  • Phase II: Independent Alternative Compliance Projects includin a credit trading system. This phase is currently in the planning stage and scheduled for implementation in 2023.

For further questions regarding Alternative Compliance, please contact Alex Gostomelskiy at 858-541-4337 or at

Drainage Design Manual

The Drainage Design Manual, which is included as an appendix to the City’s Land Development Manual, provides criteria for hydrologic and hydraulic analysis and design.

Right of Entry Permits 

Right of Entry Permits are required when requesting entry into the City of San Diego’s storm drain infrastructure.  See below for information on situations that require one, and instructions for applying for a permit.