Placentia, CA Fence Regulations: Retaining Walls (2026)

Section 20.40.040 of the Placentia Municipal Code, part of the Chapter 20.40 grading rules, sets the retaining wall trigger. Under subsection (a)(3), wherever the differential between adjoining lots exceeds two feet in elevation measured vertically at the common property line, a retaining wall shall be constructed according to specifications fixed by the chief building official. Under (a)(2), no grading, cut or fill can produce a grade differential in excess of three feet between adjacent properties measured vertically at the property line. The planning commission can permit more, but notice of the meeting must be mailed to all adjoining property owners at least seven days beforehand, and the commission must find that special circumstances in the drainage or topography of the property justify the exception, which stays the minimum required.

Retaining walls can also reduce setbacks. Subsection (b)(6) lets retaining walls be used to reduce the required setbacks, subject to the chief building official's approval. Slope setbacks are printed in (b): structures sit back from the tops and toes of slopes by one-half the height of the slope, with a minimum of three feet and a maximum of 15 feet from the toe and 10 feet from the top, and the top of any slope stays a minimum of three feet horizontally from the face of any block wall footing.

Above the wall itself, fence and wall height in a rear or side yard where a grade differential exists is a minimum of six (6) feet and a maximum of eight (8) feet above the highest finished grade (§ 23.81.100). Grading permit applications need plans signed by a registered civil engineer (§ 20.40.100), the city engineer issues grading permits (§ 20.40.080), and the owner must keep retaining walls, cribbing and drainage structures in good condition and repair (§ 20.40.060).