Standard Urban Stormwater Mitigation Plan

Standard Urban Stormwater Mitigation Plan

For questions related to projects required to prepare and implement a Standard Urban Stormwater Mitigation Plan, please visit the LA Stormwater Public Counter at 201 North Figueroa Blvd., 3rd Floor, Station 18, Los Angeles, CA  90012.

The State Regional Water Quality Control Board adopted the Standard Urban Stormwater Mitigation Plan (or SUSMP) in 2000. It was developed as part of the municipal stormwater program to address stormwater pollution from new developments and redevelopment projects.

Project applicants are required to prepare and implement a Standard Urban Stormwater Mitigation Plan when their projects fall into any of these categories:

  • Single-family hillside residential developments
  • Housing developments of 10 or more dwelling units (including single family tract developments)
  • Industrial /Commercial developments with one acre or more of impervious surface area
  • Automotive service facilities*
  • Retail gasoline outlets*
  • Restaurants*
  • Parking lots of 5,000 square feet or more of surface area or with 25 or more parking spaces
  • Projects with 2,500 square feet or more of impervious area that are located in, adjacent to, or draining directly to designated Environmentally Sensitive Areas (ESA)


* Developments of less than 5,000 square feet in these categories are only subject to the prescriptive method described in The City of Los Angeles Best Management Practices Handbook Part B, 3rd Edition.

Project applicants will be required to incorporate stormwater mitigation measures into their design plans and submit the plans to the City for review and approval. Any project that cannot comply with the Low Impact Development Ordinance requirements shall be required to comply with, at a minimum, all applicable SUSMP requirements in order to maximize onsite compliance. How to Build Protection for Mother Nature into Your Project, a guide for developers and designers includes background information on SUSMP, outlines the plan submittal and approval process and provides information on SUSMP infiltration requirements and guidelines.