Adopted in November 2010, Low Impact Development (LID) is required for all development and redevelopment projects that create, add, or replace 500 square feet or more. LID is smart, stormwater management that promotes the use of natural drainage features to slow, clean, infiltrate and capture rainfall. It's an economical and efficient way to replenish local aquifers, reduce pollution, increase the reuse of water and improve the quality of our beaches and waterways. Overall, it will help protect the Los Angeles and San Gabriel Rivers watersheds and help improve the health of the Alamitos and San Pedro Bays for both wildlife and people.

LID is a component of the National Pollutant Discharge Elimination System (NPDES) permit program. NPDES regulations consist of the Standard Urban Stormwater Mitigation Plan (SUSMP), also known as the Low Impact Development (LID) requirements, and the Stormwater Pollution Prevention Plan (SWPPP). NPDES program was created in 1972 by the Clean Water Act (CWA). The CWA helps address water pollution by regulating point sources that discharge pollutants to waters of the United States

Effective, November 12, 2013, the LID Ordinance will apply to any new development or redevelopment that results in the replacement of more than fifty percent (50%) of an existing building structure, or impervious surface area (exceptions apply - see LID Brochure).