Why Crossing 10,000 Square Feet of Impervious Area Triggers Costs Most Pro Formas Miss
How crossing the 10,000 SF impervious-area line activates San Diego's Priority Development Project regime — biofiltration, structural BMPs, and reshaped site planning that arrive together.
San Diego's stormwater regulations classify any project that creates or replaces 10,000 square feet or more of impervious surface area as a Priority Development Project (PDP), triggering structural Best Management Practice (BMP) requirements — biofiltration basins, retention systems, treatment infrastructure — that the project must accommodate on the site.
The article walks through what counts as impervious area, how the threshold reshapes site planning when a project is near the cutoff, and the cost and design implications that PDP designation adds to a developer's pro forma.