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Santa Clara County, CA Fence Regulations: Retaining Walls (2026)

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

Key Facts

Permit trigger (volume)
Over 150 cubic yards cut/fill
Permit trigger (depth)
Over 5 feet vertical cut/fill
Foundation-tied walls
Covered by building permit instead
Applies to
Unincorporated county only

Summary

A retaining wall in unincorporated Santa Clara County needs a Grading Permit once the cut or fill it creates exceeds 150 cubic yards or is deeper than five vertical feet.

City-specific rules exist: San Jose, Santa Clara, and Mountain View have their own retaining walls rules that differ from Santa Clara County's county-level regulations. If you live in one of those cities, check the city-specific page instead.

No person shall do any grading, or cause or allow the same to be done, on any real property, without obtaining a Grading Permit for the following:(a)Cuts or fills, which each independently are greater than 150 cubic yards; or(b)Cut or fill that is greater than five feet in vertical depth at its deepest point when measured from the natural ground surface; or(c)Work that alters, diverts, or impairs the flow of water in the watercourse. The volume and height specified in this section are cumulative and not annual amounts.

Source: Santa Clara County Building InspectionView official code

Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 65).

Full Breakdown

Under Ordinance Code § C12-406, any grading on unincorporated county property, including the earthwork behind a retaining wall, requires a Grading Permit if independent cuts or fills exceed 150 cubic yards, or if a cut or fill is deeper than five feet measured from natural grade. Those volume and depth thresholds are cumulative, not annual. A retaining wall tied directly to a building's foundation can instead be authorized through the building permit under the § C12-407(b) exemption. Retaining walls that stay below the grading-permit thresholds are also exempt from the county's separate design review process.

Violations & Fines

Grading in excess of the § C12-406 thresholds without a permit violates Chapter III of Division C12 and is subject to grading abatement procedures and penalties; general Ordinance Code violations are misdemeanors punishable by up to $1,000 per day under Sec. A1-28.

Frequently Asked Questions

Do I need a permit for a small retaining wall in unincorporated Santa Clara County?
Not necessarily. If the cut or fill it creates stays under 150 cubic yards and 5 feet of vertical depth, § C12-407 exempts it from a Grading Permit.
What if my retaining wall is attached to my house foundation?
It's typically covered under the building permit for the structure instead of a separate grading permit, per § C12-407(b), unless it creates an unsupported cut or fill over 5 feet deep.

Sources & Official References

Other rules in Santa Clara County

All Santa Clara County rules

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