Placer County, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Plan trigger
- >10,000 sq ft graded at >10% slope
- Watercourse buffer trigger
- grading within 50 feet
- Winterization deadline
- October 15th each year
- Grading suspension window
- October 15 to May 1
- Enforcing agency
- Community Development Resource Agency
- Violation penalty
- Misdemeanor, § 1.24.010
Summary
Unincorporated Placer County requires a separate erosion and sediment control plan on top of any grading permit once a project crosses set thresholds, such as over 10,000 square feet of graded slope steeper than 10% or grading within 50 feet of a watercourse. Rainy-season deadlines and stop-work authority back it up.
An erosion and sediment control plan shall be required whenever: 1. The graded portion of the site includes more than 10,000 square feet of area having a slope greater than 10%; 2. Clearing and grubbing of areas of one acre or more regardless of slope; 3. There is a significant risk that more than 2,500 square feet will be unprotected or inadequately protected from erosion during any portion of the rainy season; 4. Grading will occur within 50 feet of any watercourse when such watercourse is located outside of the PCCP boundary (Section 19.10.050)... 5. The community development resource agency determines that the grading will or may pose a significant erosion, or sediment discharge hazard for any reason; or 6. The site is located within the Tahoe Basin.
Full Breakdown
630 requires long-term erosion and sediment control as a primary design consideration on every grading plan, with source control emphasized over after-the-fact sediment treatment, and requires grading to be scheduled for completion or winterization by October 15th each year. 650(B) whenever the graded slope area exceeds 10,000 square feet at greater than 10% slope, clearing/grubbing covers one acre or more at any slope, more than 2,500 square feet could go unprotected during the rainy season, grading occurs within 50 feet of a watercourse (or anywhere in the stream system boundary if inside the Placer County Conservation Program boundary), the community development resource agency flags a significant hazard, or the site sits in the Tahoe Basin.
Once required, the plan must be prepared or co-signed by a civil engineer, geotechnical engineer, engineering geologist, or landscape architect, verified for structural and hydraulic adequacy, and must follow the High Sierra Resource Conservation District's Erosion and Sediment Control Guidelines for Developing Areas of the Sierras. 650(C) requires that sediment and erosion control measures be in place, or capable of being placed within 24 hours, by October 15th; the agency director may suspend grading outright between October 15 and May 1. Revegetation deadlines follow: areas graded between April 1 and October 15 must be planted by November 1st, and areas graded at other times must be planted within 15 days.
For Tahoe Basin parcels, note that county erosion-control review sits alongside, not instead of, the Tahoe Regional Planning Agency's separate best-management-practice and erosion-control requirements, which are not part of this county code.
Violations & Fines
Failure to comply with agency orders, permit conditions, or the erosion and sediment control plan is a violation of Article 15.48 under Section 15.48.690. The agency director can issue a written stop-work order under Section 15.48.710, requiring the responsible party to halt work immediately, submit a remedy plan within 24 hours, and complete corrective work within 24 hours of remedy approval, at the violator's expense. Section 15.48.720 makes any violation of the article a misdemeanor, punishable as provided in Section 1.24.010. Drainage or flooding impacts to adjacent property can also be declared a public nuisance under Section 15.48.700, with abatement costs, liens, and even treble costs on a second judgment within two years assessed against the property owner.
Frequently Asked Questions
Does every grading job in Placer County need an erosion control plan?
What happens if erosion controls are not ready by October 15th?
Are Tahoe Basin projects held to the same erosion rules?
Sources & Official References
Other rules in Placer County
California rules heatmap·Compare Placer County to another location·View the California environmental rules overview
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