Yavapai County, AZ Environmental Rules: Erosion Control (2026)

1 requires the faces of cut and fill slopes to be prepared and maintained to control erosion, which may consist of effective planting, though cut slopes made of erosion-resistant material are exempt. 2 requires check dams, cribbing, riprap or other devices where planting alone will not control erosion or provide safety. These erosion standards sit inside the county's broader drainage and terracing rules at Section 112: terraces at least 6 feet wide are required at intervals no greater than 30 feet of vertical height on cut or fill slopes, and where two or more terraces are needed, the one nearest mid-height must be at least 12 feet wide.

Swales or ditches on those terraces need a minimum 20-horizontal-to-1-vertical grade (5%), a minimum 12-inch depth and 5-foot width, and must be paved in at least 3 inches of concrete or an equivalent material; a single swale run cannot carry runoff from more than 13,500 square feet without discharging into a down-drain. Building pads must slope at 2% toward approved drainage facilities unless the Building Official waives it, and interceptor drains are required above cut slopes with a tributary width over 40 feet, at least 1 foot deep and 3 feet wide, sloped no flatter than 50-to-1 (2%) and paved in concrete.

Drainage crossing a property line cannot exceed pre-grading flows, and any erosion at a discharge point must be stopped with non-erosive down-drains. Grading is inspected by the Building Official plus the civil engineer, soils engineer and engineering geologist of record under Section 114, and under Section 115 the county will not give final approval on a grading permit until all drainage facilities and erosion-control measures are complete and as-built plans are filed.