Building on a hillside in Fontana: the local rules

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

What Fontana's code says

Fontana code What Fontana's code adds
Grading and retaining walls	At most 75 percent of the lot may be graded or disturbed. Applies: Hillside overlay district lots with an average slope of 10.0—14.9 percent. § 30-633 · code text 10.0—14.9 \| 1.75 x Lot Area in acres \| 75 At most 50 percent of the lot may be graded or disturbed. Applies: Hillside overlay district lots with an average slope of 15.0—19.9 percent. § 30-633 · code text 15.0—19.9 \| 1.00 x Lot Area in acres \| 50 At most 25 percent of the lot may be graded or disturbed. Applies: Hillside overlay district lots with an average slope of 20.0—24.9 percent. § 30-633 · code text 20.0—24.9 \| 0.50 x Lot Area in acres \| 25 No grading or other change of any kind, unless needed protective grading is shown. Applies: Hillside overlay district; parts of a lot with a slope of 25% or greater. § 30-633 · code text Portions of the lot with a slope of 25% or greater shall be maintained in a natural condition, without alteration of any sort, including, but not limited to, grading operations Retaining walls may be no higher than 4 feet. Applies: Walls upslope from a building pad in a hillside overlay district. § 30-633 · code text Upslope (from a building or structure) walls shall not exceed four feet in height. Retaining walls may be no higher than 3 feet. Applies: Walls downslope from a building pad in a hillside overlay district. § 30-633 · code text Down slope (from a building or structure) walls shall not exceed three feet in height. Each terraced wall may be no higher than 3 feet, with at least 3 feet between walls. Applies: Terraced retaining walls in a hillside overlay district. § 30-633 · code text Terraced walls shall not exceed three feet in height and shall be separated by a minimum of three feet, with appropriate landscaping as approved by the Director of Community Development.
Height on hillside lots	No part of a home may be taller than 25 feet. Applies: Homes in a hillside overlay district, measured from natural grade. § 30-633 · code text No portion or architectural feature of a home shall exceed a height of 25 feet as measured from the natural grade at the point of measurement;
When hillside rules apply	A slope of 10 percent or greater requires a hillside development permit. Applies: Projects in a hillside overlay district, including building and grading permits. § 30-631 · code text All projects within a hillside overlay district and located on a lot with a slope of ten percent or greater shall be subject to review and approval of a hillside development permit (HDP)

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Frequently asked questions

What extra rules apply to a hillside lot in Fontana?

Fontana's code: A slope of 10 percent or greater requires a hillside development permit. (Projects in a hillside overlay district, including building and grading permits.) (§ 30-631); At most 75 percent of the lot may be graded or disturbed. (Hillside overlay district lots with an average slope of 10.0—14.9 percent.) (§ 30-633).

Building on a hillside in Fontana

What Fontana's code says

Who this affects

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