Placentia, CA Environmental Rules: Erosion Control (2026)

Section 20.40.040(c)(10) of the grading chapter sets the core rule. Other unprotected graded surfaces must be planted, paved or built upon, or provided with berms and approved drainage facilities adequate to prevent erosion and to carry runoff of surface waters to an approved place of discharge. The section states its intent to prohibit abandoning graded areas or slopes that lack erosion protection and adequate drainage facilities, even where every other requirement was met and approved.

Companion drainage rules in the same section back this up. Berms must be provided and maintained at the top of all banks or graded slopes unless the site slope exceeds one-fourth inch per foot toward an approved discharge point (§ 20.40.040(c)(4)). Terraces at least six feet wide are established at not more than 30 foot vertical intervals on slopes (§ 20.40.040(c)(5)). Drainage facilities must prevent erosion of ground in the discharge area by nonerosive downdrains or other devices (§ 20.40.040(c)(7)).

Section 20.40.050 adds site conduct rules. Grading is permitted only between seven a.m. and seven p.m. Monday through Friday and nine a.m. and six p.m. on Saturday, and is prohibited on Sunday and federal holidays unless the chief building official or city engineer approves other hours for an emergency. Graded surfaces and stockpiles are wetted, protected or contained to prevent dust or spillage onto adjoining property or streets (subsection (b)). No grading can cause excessive erosion or flooding (subsection (e)). Dirt, rocks or mud tracked onto paved streets is removed daily to the city engineer's satisfaction (subsection (f)). The city engineer or chief building official can require temporary debris basins to control erosion (subsection (g)). Grading needs a permit issued by the city engineer (§ 20.40.080), and the owner maintains protective devices including protective planting (§ 20.40.060).