Stormwater discharges are regulated under the 1972 Clean Water Act's National Pollutant Discharge Elimination System (NPDES). There are several types of activities regulated under the NPDES program such as construction, municipal, and industrial activities.
The MS4 permit requires all permittees participating in a Watershed Management Program (WMP) to have final Low Impact Development (LID) ordinances and green streets policies in place. As part of this overall compliance effort by the City, Chapter 13.20 Stormwater and Urban Runoff Pollution Control of the El Monte Municipal Code is enhanced to include LID regulations and green streets policies. LID employs principles such as preserving and recreating natural landscape features, minimizing effective imperviousness to create functional and appealing site drainage that treat stormwater as a resource rather than a waste product. By implementing LID principles and practices, water can be managed in a way that reduces the impact of built areas and promotes the natural movement of water within an ecosystem or watershed.