Redwood City, CA Fence Regulations: Retaining Walls (2026)

Redwood City folds retaining walls into its grading regulations rather than a stand-alone wall ordinance. 53 adds a definition of "Engineered Grading" to Appendix J of the Building Code: any excavation over two feet deep, a cut slope over five feet high, fill placed on natural grade steeper than 20 percent, fill over three feet high, fill that supports a structure, or more than 50 cubic yards of fill. Because most retaining walls hold back fill or support a structure, they typically trigger this Engineered Grading standard rather than the ordinary grading exemption.

2 so a grading permit is not required only for isolated, self-contained grading under 50 cubic yards that poses no danger to the public or adjoining property, and even that exemption drops away once the work meets the Engineered Grading definition. 3, requiring the applicant to deposit funds at the time of filing to cover the City's actual engineering costs for plan review and inspection, billed at the City Engineer's fully burdened hourly rates on file with the City Clerk, and it states directly that separate plan review and permit fees apply to retaining walls or major drainage structures.

54 also transfers Appendix J review authority from the Building Official to the City Engineer citywide, so retaining wall plans are checked by the Engineering Division rather than the Building Division. There is no locally published maximum height exempt from permit; any wall meeting the Engineered Grading criteria needs engineered plans and City Engineer sign-off regardless of height, and undersized walls can still be pulled into the requirement once combined fill volume passes 50 cubic yards.