Concord ADU Rent Increase: Start With the Legal Status
Concord adu rent increase decisions begin with one question: is the unit actually an ADU under the current ordinance? A converted garage, a basement apartment, or a detached cottage may look like an ADU but not qualify if it wasn’t permitted as one. Concord’s rent ordinance exempts ADUs from its rent caps, but that exemption only protects you if the unit meets the city’s definition. Pull the permit history early. If the unit was built as a second dwelling without proper approvals, you may be facing a different set of rules altogether—and a different conversation with the tenant.
This matters because the exemption is not automatic. A landlord who assumes an unpermitted conversion is an ADU can issue a notice that later gets challenged. The city’s enforcement arm looks at the permit record, not the landlord’s intent. Before you calculate a new rent figure, confirm the unit’s legal status with the city’s planning or building department. That step alone often reshapes the whole increase plan.
The Real Challenge: Two Sets of Rules Overlap
Here’s what most landlords get wrong: they think Concord’s local rent ordinance is the only rule, or they think AB 1482 is the only rule. In practice, a Concord ADU sits under both. The local ordinance exempts ADUs from its rent caps and just-cause eviction requirements, but AB 1482—the statewide rent control law—has its own separate exemption for units with a certificate of occupancy issued within the last 15 years. If your ADU is older than that, AB 1482 still applies even though Concord’s ordinance exempts it. That means you may be limited by the statewide cap on annual increases, which is tied to inflation and changes each year.
The overlap creates confusion. A landlord who reads only the Concord ordinance might think they can raise rent freely. A landlord who reads only AB 1482 might think the 15-year exemption is the only path. The truth is you need to check both, and the sequence matters. Confirm the local exemption first, then determine whether the statewide exemption applies to your unit’s age. If it doesn’t, the statewide cap becomes your ceiling, not your floor.
Pull the 2019 Base Rent or Your Own History
If AB 1482 applies to your ADU, the base rent for calculating increases is generally the rent in effect on March 15, 2019. If the unit was not rented on that date, the base is the initial rent charged to the first tenant after that date. For many Concord landlords, this means digging through old leases, bank statements, or property management records. If you bought the property after 2019, you may need to request the rent history from the seller or their agent—and if that history is incomplete, you may be forced to use a lower base than reality.
Even if your ADU is exempt from AB 1482 because it’s newer than 15 years, you still need your own rent history for practical reasons. A tenant who challenges an increase will ask for the record. A judge or mediator will ask for the record. Having a clean, dated ledger of every rent change since the unit was first rented makes any increase defensible. If you don’t have that, start reconstructing it now—before you send a notice. Our guide on Concord Rent History Verification Before Setting Base Rent walks through the documents that matter most.
Decide Whether the 15-Year AB 1482 Exemption Helps
The 15-year exemption in AB 1482 applies to units with a certificate of occupancy issued within the last 15 years. For a newly built ADU, that exemption likely applies—meaning the statewide cap does not limit your increase. But the exemption is not permanent. Once the unit turns 15 years old, AB 1482 kicks in automatically. If your ADU is 12 or 13 years old, you have a narrow window to set a higher rent without the statewide cap. If it’s 16 years old, that window is closed.
This is where the decision gets real. A landlord with a 14-year-old ADU might choose to issue a larger increase now, knowing the cap will apply in a year. A landlord with a 16-year-old ADU has no such flexibility. The decision also interacts with Concord’s local rules. Even if AB 1482 exempts your ADU, Concord’s ordinance may still require a specific notice period or a registration step. Check both before you act. Our article on Concord ADU Rent Increase: Exemptions and Notice Rules breaks down the notice requirements in plain language.
How We Walk You Through This
When a Concord landlord brings us an ADU increase question, we start with a document review. You send us the permit record, the lease history, and any prior notices. We map the unit against the current Concord ordinance and the current AB 1482 rules. We identify which exemptions apply and which don’t. Then we build a timeline: what you can do today, what you can do in six months, and what changes when the unit ages out of an exemption.
We also handle the notice itself. The form, the timing, the delivery method—each has a specific requirement, and a mistake can reset the clock or invalidate the increase. We prepare the notice, you approve it, and we track the effective date. If the tenant challenges, we help you assemble the evidence. This is not a one-size-fits-all process; it’s a checklist tailored to your unit’s exact status. For landlords who manage multiple properties, our property management service includes this review as part of the annual rent-setting cycle.
What to Do Before You Send Any Notice
Here’s the pre-increase checklist in order:
- Confirm the unit’s legal status as an ADU with the city’s permit records.
- Determine whether Concord’s local rent ordinance exempts the unit (it generally does for ADUs, but verify the current text).
- Pull the 2019 base rent if AB 1482 applies, or your full rent history if the unit is newer.
- Check the certificate of occupancy date to see if the 15-year AB 1482 exemption applies.
- Calculate the maximum increase under whichever rule binds you—local, statewide, or both.
- Prepare the notice with the correct form and timing for your situation.
- Keep a copy of everything: permit, lease, ledger, notice, proof of service.
If any step feels uncertain, stop and verify. A wrong assumption about an exemption can turn a routine increase into a dispute. The cost of checking is an afternoon; the cost of guessing is a hearing.
For a deeper look at how Concord’s rules interact with your financing decisions, read Concord Rent Caps: Refinance or Line of Credit? It covers the cash-flow side of the same equation.
If you want a second set of eyes on your ADU’s status before you raise the rent, contact us and we’ll walk through the checklist together.
What’s the one document you’re missing most often when you start this process—the permit, the 2019 lease, or the certificate of occupancy?
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.
