California Security Deposit Rules: What Every San Diego Landlord Needs to Know

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Security deposits are one of the most litigated areas in California residential property management. The rules are specific, the deadlines are firm, and the penalties for noncompliance can exceed the deposit itself. If you’re a new landlord in San Diego, understanding this framework from the start will save you significant time, money, and stress.

How Much Can You Charge?

As of July 1, 2024, California law (AB 12) limits security deposits to one month’s rent for most residential properties — regardless of whether the unit is furnished or unfurnished. The prior two-month limit for unfurnished units and three-month limit for furnished units no longer apply.

There is a narrow exception for small landlords who own no more than two residential properties totaling no more than four units. Those landlords may still collect up to two months’ rent for an unfurnished unit. If you fall outside that exception, one month’s rent is the cap.

What Can You Deduct — and What’s Off Limits?

California law allows deductions for unpaid rent, cleaning to restore the unit to its move-in condition, and repair of damage beyond normal wear and tear. The phrase “normal wear and tear” matters: scuffs on walls, worn carpet in high-traffic areas, and minor nail holes generally do not qualify as deductible damage.

Deductions for general cleaning — beyond what’s needed to restore the unit — are not permitted if the resident maintained the unit in a reasonably clean condition throughout the tenancy. Document the move-in condition thoroughly. A signed move-in checklist and timestamped photos protect you in any dispute.

The 21-Day Rule

After a resident vacates, you have 21 calendar days to either return the full deposit or mail an itemized statement with any remaining balance. If you make deductions, each item must be described with its cost. For repairs exceeding $125, you must include receipts or good-faith estimates.

Missing the 21-day window — or failing to provide proper documentation — can result in the court awarding the resident up to twice the amount of the deposit in bad faith penalties, in addition to the deposit itself. The deadline starts the day the resident surrenders possession, not the day the lease ends.

Move-In and Move-Out Documentation

The best protection you have in any security deposit dispute is documentation. Conduct a written move-in inspection with the resident present. Use a detailed checklist, take photographs, and keep dated copies. Repeat the process at move-out.

California requires that you offer the resident a pre-move-out inspection — a walkthrough to identify issues they can address before final departure. This is not optional; failing to offer it can limit your ability to make deductions later.


The 21-day clock and the documentation requirements are where most landlords run into trouble — not because they intended to keep the deposit improperly, but because they didn’t know the rules. Getting this right from the start is straightforward when you understand the framework.

One More Thing: Interest and Separate Accounts

California does not currently require landlords to hold deposits in separate accounts or pay interest on them. However, some jurisdictions — including parts of San Diego County — may have local ordinances that add requirements. If you’re managing property in the City of San Diego or another incorporated area, verify whether local rules apply.

The Bottom Line

California’s security deposit rules are detailed, but they’re manageable. Know your deposit cap, document the unit’s condition thoroughly, meet the 21-day deadline, and itemize every deduction. If you’re uncertain about a specific situation — or managing a property in a rent-controlled jurisdiction — it’s worth a conversation with a licensed property manager before you act.


Let’s talk about what you’re navigating. Cambridge Management Group works with San Diego landlords at every stage — including new owners getting the fundamentals right from day one.

This article is for informational purposes only and does not constitute legal, financial, tax, or professional advice.

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