San Rafael, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Max graded slope
- 2:1 (steeper needs engineer approval)
- Max retaining wall
- 8 feet without Planning Commission OK
- SWPPP required
- subdivisions of 5+ acres
- Drainage rule
- lots must drain to a street
Summary
San Rafael caps graded slopes at 2:1 and retaining walls at 8 feet for new subdivisions, and requires an erosion control plan and city engineer sign-off on drainage.
All subdivisions shall be designed and improved to provide proper grading, drainage and erosion and sediment control. All subdivisions shall comply with the provisions of the Uniform Building Code for design of grading and the conveyance of drainage and stormwater runoff and shall comply with best management practices (BMPs). The following design standards shall be required:
(a)Grading. Grading required for a subdivision shall meet the following standards:(1)Grading shall be designed to create a natural appearance to the extent possible. Graded slopes shall be designed to transition to adjacent properties so as to limit abrupt changes in topography.(2)Graded slopes shall not exceed two to one (2:1), unless the city engineer determines that a steeper slope is justified to minimize the amount of grading or to reduce potential tree removal and, where it is determined that the soil and geologic conditions are suitable for and capable of accommodating a steeper slope.(3)The finished lot grading shall provide a building site and usable yard area that is compatible with the surrounding pattern of development.(4)Retaining walls and/or stepped foundations shall be encouraged in areas to reduce grading and tree removal. Retaining walls shall not exceed eight feet (8') in height, unless approved by the Planning Commission.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 37).
Full Breakdown
San Rafael Municipal Code § 15.06.110 requires every subdivision to be designed with proper grading, drainage, and erosion and sediment control, complying with Uniform Building Code grading provisions and best management practices. Graded slopes may not exceed 2:1 unless the city engineer finds a steeper slope justified by soil and geologic conditions, and retaining walls may not exceed 8 feet unless approved by the Planning Commission. New lots must drain to a public or private street rather than onto adjacent property, an erosion control plan is required wherever grading occurs, and a Stormwater Pollution Prevention Plan is required for subdivisions of 5 acres or more. This governs land divided by the subdivision process inside San Rafael city limits; it does not apply in unincorporated Marin County.
Violations & Fines
Grading, erosion control, and drainage plans are reviewed and conditioned by the city engineer as part of subdivision improvement plan approval; a grading permit will not issue without compliance, and noncompliant slopes or walls require discretionary Planning Commission or city engineer approval.
Frequently Asked Questions
Can a developer grade a slope steeper than 2:1?
Is a stormwater plan always required?
Sources & Official References
Other rules in San Rafael
California rules heatmap·Compare San Rafael to another location·View the California environmental rules overview
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