Concord ADU rent cap exemption is real, but it doesn’t mean your accessory dwelling unit escapes every rent law. The city’s rent stabilization ordinance carves out ADUs, yet California’s AB 1482 still applies to most of them. That split creates a practical problem: you follow one set of rules for the local cap and a different set for the state cap, and the notices are not interchangeable. Get the distinction wrong and you either under-raise the rent or serve a notice that doesn’t hold up.
What Concord’s Rent Cap Actually Exempts
Concord’s rent stabilization ordinance, as it currently stands, exempts accessory dwelling units from the city’s rent cap and just-cause eviction provisions. That exemption applies whether the ADU is attached or detached, and it doesn’t depend on when the unit was built. The city’s logic is straightforward: ADUs are newer housing stock, often built by owner-occupants, and the ordinance aims to preserve that incentive.
But the exemption is not a blanket pass. Concord’s ordinance still requires you to register the unit and provide the tenant with a written notice of exemption within a specific timeframe after the tenancy begins. The notice must state that the unit is an ADU and therefore not subject to the city’s rent cap. If you skip that notice, you may lose the exemption’s protection and find yourself arguing about it later.
AB 1482: The State Cap That Still Applies
AB 1482, the California Tenant Protection Act, caps annual rent increases for most residential units at the lower of the local rate or a state-set percentage plus the regional consumer price index. The state cap applies unless the property is explicitly exempt, and ADUs are not on the state’s exemption list. So even though Concord’s local cap doesn’t touch your ADU, the state cap generally does.
That means you calculate your maximum increase using the state formula, not the city’s. The state cap changes each year based on inflation data, so the number you used last year may not be valid this year. You also need to check whether your ADU qualifies for any state-level exemption—for example, if it’s a single-family home with no corporate ownership, or if it’s a duplex where the owner lives in one unit. Those exemptions are narrow, and they require you to serve a specific notice to the tenant to claim them.
Concord ADU Rent Cap Exemption: The Notice Problem
The most common mistake we see is serving the wrong notice. Concord has its own exemption notice form for ADUs, and AB 1482 has a separate notice for claiming a state-level exemption. They look similar, they both mention rent caps, and they both go to the tenant. But they do different legal work.
If you serve the Concord ADU exemption notice, you’ve satisfied the city’s requirement. That does nothing for AB 1482. If you want to claim a state exemption—say, because you own the property as an individual and it’s a single-family home with an ADU—you must serve the state’s notice as well. Serving one does not cover the other. And if you serve neither, you’re stuck with the stricter of the two caps, which in practice means the state cap for most ADUs.
Calculating the Lawful Increase, Step by Step
Here’s the process we walk through with Concord landlords. First, confirm the unit is actually an ADU under the city’s definition—not a converted garage that was never permitted, not a junior ADU, not a second unit that predates the current ordinance. The definition matters because the exemption only applies to true ADUs.
Second, check the current AB 1482 cap. The state publishes the allowable increase each year, and it’s based on the regional CPI. You cannot use last year’s number. You also need to confirm whether any local rent registry or just-cause rules still apply to your ADU even if the cap doesn’t—Concord’s ordinance has separate provisions that may still govern evictions or registration.
Third, determine your notice period. AB 1482 requires a longer notice for increases above a certain threshold, and that threshold changes. For most increases, you need to give at least 30 days’ written notice, but if the increase is above the state’s threshold, you need 90 days. The notice must include the specific dollar amount, the effective date, and a statement that the increase complies with AB 1482.
Fourth, serve both the Concord ADU exemption notice (if you haven’t already) and the AB 1482 notice if you’re claiming a state exemption. Keep proof of service. If you use a property management system, this is where it earns its keep—automated reminders and document storage prevent the “I forgot to serve the notice” problem that turns a lawful increase into a refund.
Where This Gets Complicated
The interplay between Concord’s ordinance and AB 1482 is not intuitive. For example, Concord’s rent cap has a lower annual limit than the state’s in some years, but since your ADU is exempt from the local cap, you use the state number. However, if your ADU is attached to a single-family home and you own it as an individual, you might qualify for the state’s single-family home exemption—but only if you serve the right notice. Miss that notice, and you’re back to the state cap.
There’s also the question of what happens when the tenant challenges the increase. If you served the Concord notice but not the AB 1482 notice, and the tenant files a complaint, you may have to refund the difference. The city’s rent board or a court will look at whether you complied with the stricter rule, not the more lenient one. That’s why we tell landlords to treat the two notices as separate compliance tasks, each with its own deadline and proof requirement.
How We Walk You Through It
When you work with us on this, we start by pulling your property’s specifics: the ADU’s permit status, the ownership structure, and the current lease terms. Then we map the two rule sets side by side—what Concord requires, what the state requires, and where they overlap. We draft the notices for you, with the correct dates and dollar amounts, and we set reminders for the notice periods so nothing slips.
We also connect this to your broader property operations. If you’re using a property management system, we make sure the rent increase workflow is built in: the calculation, the notice generation, and the proof of service all happen in one place. If you’re still on spreadsheets, we can help you set up a simple checklist that prevents the most common errors. And if you’re dealing with multiple properties across Concord and Walnut Creek, we keep the local variations straight—because Walnut Creek’s rules are different, and mixing them up is expensive.
For a deeper look at the state cap itself, our AB 1482 Rent Cap Concord: Compliance for Landlords article walks through the state formula and the exemptions in more detail. And if you’re still unsure whether your unit qualifies as an ADU under Concord’s definition, Concord ADU Rent Increase: Exemptions and Notice Rules covers the local exemption criteria and the notice requirements.
If you’d rather have someone else handle the notices and the math, get in touch with our team. We’ll review your specific situation and tell you exactly what applies—no guesswork, no generic advice.
What’s Your Biggest Confusion?
When you think about raising rent on your Concord ADU, which rule trips you up more: the local exemption notice or the state cap calculation? Tell us in the comments—we read every one.
About this article. This is general information and our own opinion, written from how we run operations for owners and businesses in Contra Costa County. It is not legal, tax, accounting, financial or other professional advice, it is not a recommendation to take or avoid any action, and it is not a substitute for advice about your own property, tenancy or business. CAO Investment Group is not a law firm, and reading this does not create an attorney-client or any other professional relationship. Local ordinances, fee schedules, forms, thresholds and deadlines change often and differ from city to city within Contra Costa County — anything here may be out of date by the time you read it, including as of the publication date shown above. Verify anything you plan to rely on against the current rules published by your own city or county, and speak to a qualified attorney, CPA or licensed professional about your specific situation before you act. We make no warranty that this information is current, complete or accurate, and we accept no liability for any action taken or not taken on the basis of it.
