Apple Valley, CA Environmental Rules: Stormwater Management (2026)

100, Drainage Facilities and Storm Water Runoff, governs how new residential projects manage rainfall inside town limits. Obstructing, diverting, bridging or confining a natural drainage channel in a way that damages other properties is prohibited outright. For projects that go forward, peak storm water pass-through runoff after development must be at least 10% less than the pre-development runoff, calculated using the County of San Bernardino Hydrology Manual and a 100-year design storm, as determined by the Town Engineer. Separately, every proposed development must capture, retain and infiltrate 100% of a 100-year, one-hour storm event that falls on the site.

The Code favors natural-looking retention through common-area retention or detention basins, storm water chambers and dry wells over engineered channels; concrete channels are to be avoided, and any channel the Town Engineer requires must use plants and stone lining where feasible. Basin depth is capped by size: a retention or detention basin smaller than one acre cannot exceed four feet in depth, and a basin one acre or larger cannot exceed eight feet, unless the Planning Commission approves a deeper basin under a Development Permit.

75, Water Conservation/Landscaping Regulations, with a landscape assessment district formed for ongoing maintenance of shared basins. Individual lot retention or detention basins are not allowed in new subdivisions; the Code requires common facilities instead. Dry wells in parking areas or street rights-of-way must use an interceptor well built to Town standards, and every retention basin must include dry wells or similar devices able to infiltrate the full design volume within 72 hours of a storm.