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Redlands, CA Fence Regulations: Retaining Walls (2026)

Some Restrictions
Compiled from the official code textEditor Martyn O'NeillLast verified September 2026

Key Facts

Engineering requirement
Must resist all imposed loads
Guardrail trigger height
Over 30 inches
Required guardrail height
At least 3 feet above grade
Guardrail gap limit
No 9-inch sphere passage
Steep-slope wall cap
6 feet (30 inches in front yard)
Governing section
City Code § 18.212.040
Violation classification
Misdemeanor, per section 18.208.050

Summary

Redlands requires retaining walls to be engineered to resist all imposed loads and built of concrete, masonry, or treated wood. Any wall over 30 inches tall must carry a 3-foot-high fence, wall, or guardrail above the highest adjacent grade, with no 9-inch gaps in open guardrails.

A. For the purpose of this chapter, retaining walls shall be essentially vertical, and shall be constructed of concrete, masonry, or wood treated with an approved preservative under the treating and quality control requirements specified in the uniform building code standards 25-12, or wood of natural resistance to decay, as defined in chapter 25 of the uniform building code. B. Such retaining walls shall be engineered to resist all imposed loads. C. All retaining walls exceeding thirty inches (30") in height shall have a fence, wall or guardrail at least three feet (3') above the highest adjacent ground level. In open guardrail type fencing, intermediate members shall be so placed that a sphere nine inches (9") in diameter cannot pass through.

Full Breakdown

212's Land Development Standards, Redlands treats retaining walls as engineered structures, not ordinary yard fencing. Walls must be essentially vertical and built of concrete, masonry, or wood treated to Uniform Building Code Standard 25-12 (or naturally decay-resistant wood under UBC Chapter 25), and every wall must be engineered to resist all imposed loads, meaning a homeowner cannot simply stack block without calculations for a wall of any real height. The safety trigger is 30 inches: once a retaining wall exceeds that height, the code requires a protective fence, wall, or guardrail at least 3 feet above the highest adjacent ground level, and if the guardrail uses open members, they must be spaced so a 9-inch sphere cannot pass through, the same anti-entrapment spacing used for pool fencing elsewhere in the code.

220: retaining walls generally may not exceed 6 feet, front-yard retaining walls are capped at 30 inches, and a combined retaining wall plus required guardrail may not exceed 9 feet overall, dropping to 6 feet total if the wall and guardrail sit within 15 feet of an existing dwelling. 100.

Violations & Fines

Retaining wall work done without meeting the grading permit and engineering requirements of Chapter 18.212 is enforced as a general Title 18 violation. Under section 18.208.050, any person who violates a provision of the zoning title is guilty of a misdemeanor, and each day the violation continues counts as a separate offense, so an unpermitted or unguarded wall can generate cumulative daily exposure until it is corrected or a minor exception is obtained.

Frequently Asked Questions

How tall can a retaining wall be in Redlands before I need a guardrail?
Once a retaining wall exceeds 30 inches in height, City Code section 18.212.040 requires a fence, wall, or guardrail at least 3 feet above the highest adjacent ground level. Open guardrails must be spaced so a 9-inch sphere cannot pass through the gaps.
Do Redlands retaining walls need engineering calculations?
Yes. Section 18.212.040(B) states retaining walls shall be engineered to resist all imposed loads, and walls must be built of concrete, masonry, or wood treated to Uniform Building Code Standard 25-12.
Is there a different height limit on sloped lots?
Yes. On lots with a natural slope steeper than 5 percent, section 18.212.220 caps retaining walls at 6 feet generally, 30 inches in front yards, and limits a combined wall-plus-guardrail to 9 feet, or 6 feet if within 15 feet of a dwelling.
What if my planned wall exceeds these limits?
You can apply for a minor exception permit under sections 18.168.050 through 18.168.100. A committee of the community development director or designee and two planning commissioners decides the request after a 10-day notice period to adjacent property owners.
What happens if I build a noncompliant retaining wall?
Section 18.208.050 makes violating any Title 18 zoning provision a misdemeanor, with each day the violation continues treated as a separate offense, so an unguarded or unengineered wall carries ongoing daily exposure until corrected.

Sources & Official References

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