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San Diego County · Building on your lot

Building on a hillside in San Diego County

San Diego County's own rules on building on a hillside, with the code text for every value.

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Each rule below links to the section of the San Diego County Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What San Diego County's code says

San Diego County code What San Diego County's code adds
Grading and retaining walls
  • Encroachment may not exceed 10% of the steep slope area over 25% grade.
    Applies: Steep Slope areas on the Land Use Plan map; parcels of 1 acre or less may use up to 2,000 square feet or 20%.
    § 9314 · code text
    Any encroachment into steep slope areas over 25% shall not exceed 10% of the steep slope area over 25% grade.
  • New on-site access roads: at most 300 feet or one-third of the parcel depth, whichever is less.
    Applies: Steep Slope areas on the Land Use Plan map; longer roads need Planning Commission approval.
    § 9314 · code text
    Grading for access roads and driveways should be minimized; the standard for new on-site access roads shall be a maximum of 300 feet or one-third the parcel depth, whichever is less.
When hillside rules apply
  • No development or grading on natural slopes of 25% or more, except the minimum reasonable use of a property.
    Applies: Steep Slope areas on the Land Use Plan map.
    § 9314 · code text
    No development, grading, planting, excavation, deposit of soil or other material, or removal of natural vegetation, except as may be necessary f or fire safety or installation of utility lines, shall be permitted on steep natural slopes of 25% grade or greater.

Who this affects

HomeownersContractorsDesigners

Frequently asked questions

What extra rules apply to a hillside lot in San Diego County?

San Diego County's code: No development or grading on natural slopes of 25% or more, except the minimum reasonable use of a property. (Steep Slope areas on the Land Use Plan map.) (§ 9314); Encroachment may not exceed 10% of the steep slope area over 25% grade. (Steep Slope areas on the Land Use Plan map; parcels of 1 acre or less may use up to 2,000 square feet or 20%.) (§ 9314).

General information, not legal advice.

Ask about a specific San Diego County property

Ask GoCodebook how San Diego County's building on a hillside rules apply to your situation and get an answer that cites the section.

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