Thousand Oaks, CA Environmental Rules: Erosion Control (2026)
Key Facts
- Governing rule
- TOMC § 7-3.07 (Permits required)
- Extra approval trigger
- Natural slope greater than 25% needs Planning Commission/Council approval
- Small-project exemption
- Excavations under 50 cubic yards or 2 feet deep are generally exempt
- Bond requirement
- Required for excavations/fills over 50 cubic yards (§ 7-3.15)
- Penalty
- Separate Code-violation offense for each day of noncompliance (§ 7-3.26)
Summary
Thousand Oaks requires a City-issued grading permit before anyone excavates, fills, or relocates earth on a property, and additional Planning Commission or City Council approval for grading on natural slopes steeper than 25%. Minor work (small excavations or shallow fills under 50 cubic yards) is exempt, but anything larger triggers the full permit and bonding process.
No person shall commence or perform any grading or relocation of earth, and no person shall import or export any earth materials to or from any grading site without first having obtained a grading permit. No person shall commence or perform any grading or relocation of earth on land having a natural slope greater than twenty-five (25%) percent without first obtaining approval from the Planning Commission or City Council. A separate grading permit shall be required for each site. Off-site grading may be permitted, if such grading is approved in conjunction with a development permit or other entitlement. Exceptions:
(a) An excavation which does not exceed fifty (50) cubic yards or is less than two (2’) feet in depth, or which does not create a cut slope greater than five (5’) feet in height and steeper than two (2) horizontal to one vertical, unless the cut slope is made in an area of adverse geological conditions;
(b) A fill less than one (1’) foot in depth and placed on natural terrain with a slope flatter than five (5) horizontal to one vertical, or less than three (3’) feet in depth, not intended to support structures, which fill does not exceed fifty (50) cubic yards on any one lot and does not obstruct a drainage course;
(c) Excavations below the finished grade for basements and footings of buildings, retaining walls, swimming pools, or other structures authorized by a valid building permit. This shall not exempt any fill made with materials from
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-78: 2026 S-78 Supplement contains: Current city legislation passed through March 31, 2026).
Full Breakdown
Under TOMC § 7-3.07, a grading permit from the City Engineer is required for essentially all earth-moving work, including importing or exporting fill material, with a separate permit needed for each site. Slopes steeper than 25% require Planning Commission or City Council sign-off in addition to the standard permit. Limited exceptions exist for small excavations under 50 cubic yards or 2 feet deep, shallow fills that don't obstruct drainage, and excavations for building footings already covered by a valid building permit. Permits require engineering plans, and for excavations/fills over 50 cubic yards, a bond or cash deposit guaranteeing compliance (§ 7-3.15).
Violations & Fines
Grading without a permit, or violating permit conditions or City grading rules, is a Code violation under § 7-3.26, with each day of continued violation treated as a separate offense. The City Engineer can also issue stop-work orders for noncompliant grading.
Frequently Asked Questions
Do I need a permit to regrade part of my yard?
Is there a separate rule if my property is on a hillside?
Sources & Official References
Other rules in Thousand Oaks
California rules heatmap·Compare Thousand Oaks to another location·View the California environmental rules overview
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