Rancho Cucamonga, CA Fence Regulations: Retaining Walls (2026)
Key Facts
- Governing section
- Development Code § 17.48.020(A)
- Exemption threshold
- Under 36 inches in height
- Terraced walls
- Not exempt; see hillside standards §17.122.030
- Height measurement
- Mid-point method on sloped lots, §17.48.030(A)
- Adjacent wall separation
- 3 feet minimum, §17.48.030(B)
Summary
Retaining walls under 36 inches are exempt from Rancho Cucamonga's fence chapter under Development Code Section 17.48.020(A), while taller walls, or terraced retaining walls on hillside lots, must meet hillside development standards under Section 17.122.030 and the general height-measurement rules of Section 17.48.030.
Retaining walls. Retaining walls less than 36 inches in height are exempt from the requirements of this chapter except for terraced walls as required in section 17.122.030 (Hillside Development). ... Height measurement. Fence and wall height shall be measured from the finish grade at the base of the fence or wall to the uppermost part of the fence or wall; except when there is a difference in the ground level between two adjoining parcels, the fence or wall shall be measured at the mid-point of the retaining wall height as measured on the side with the lowest finish grade.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: rev 4999536; v21 updated 2026-07-15).
Full Breakdown
" That means a low retaining wall skips site development review entirely, while a wall of 36 inches or taller, or any terraced retaining wall regardless of height, is pulled into the chapter's review process and the hillside development standards. 030-1 illustrating the calculation. 030(B) separately requires a minimum three-foot separation between adjacent garden or terrace walls. 48 fence/wall standards and a distinct hillside review depending on lot grade and wall configuration. Property owners building a retaining wall at or above the 36-inch threshold should expect a building permit for structural review (soil bearing, drainage, and engineering) in addition to any required planning entitlement.
Violations & Fines
A retaining wall built at or above 36 inches, or a terraced wall on a hillside lot, without going through the required site development review or hillside development standards can be cited by code enforcement and required to be modified, permitted after the fact, or removed if it fails structural or grading review. Unpermitted retaining walls that affect drainage or slope stability can also trigger a stop-work order from the building official pending an engineered plan.
Frequently Asked Questions
Do I need a permit for a short retaining wall in Rancho Cucamonga?
What happens once a retaining wall hits 36 inches?
How is a retaining wall's height measured on a sloped lot?
Sources & Official References
Other rules in Rancho Cucamonga
California rules heatmap·Compare Rancho Cucamonga to another location·View the California fence regulations overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
Retaining Walls in Nearby Cities
How other cities in San Bernardino County handle retaining walls.