Palm Springs, CA Environmental Rules: Erosion Control (2026)

090 of the Stormwater Management chapter requires anyone performing construction work in Palm Springs to comply with Riverside County Ordinance 457, the county's erosion and sediment control ordinance, a copy of which is kept on file at the city clerk's office rather than restated in the municipal code itself. 100, which lets the City Engineer require hydrology and hydraulic calculations, drainage area maps, and erosion and sediment transfer studies for a project before approving grading. New development and redevelopment must retain on-site the incremental volume of stormwater runoff generated between undeveloped and developed conditions for the worst-case one, three, six or 24-hour hundred-year storm, using a maximum design percolation rate of two inches per hour, which drops to zero unless the applicant provides site-specific data proving otherwise.

Single-family in-fill lots in a drainage area that is 70 percent or more developed are exempt from on-site retention unless the lot is a hillside site, and non-residential in-fill projects of two acres or less get the same exemption in a built-out drainage area. Retention basins cannot use more than 40 to 50 percent of any parkway or setback landscape area, balancing drainage capacity against streetscape design, and the City Engineer must approve basin side slopes and depth. 68.