The Concord ADU rent exemption starts with the ordinance text
Concord adu rent exemption questions usually come up in the same moment: you hand over a notice for a larger increase, and the tenant says the duplex across the street is capped. They’re not wrong about the duplex. They’re just looking at the wrong building type. Concord’s rent ordinance treats an accessory dwelling unit differently from a duplex, and the difference is written into the exemption section, not hidden in a footnote. The first thing to do is get the actual ordinance language in front of both of you. The city’s municipal code is online, and the rent stabilization chapter lists the categories that are excluded from the cap. ADUs are on that list. Duplexes are not, unless the owner lives in one of the units. That single sentence is the whole explanation, but it only works if you can point to it.
What most landlords get wrong is trying to explain the policy reason before the legal fact. The tenant doesn’t care yet why the city exempted ADUs. They care whether you’re allowed to raise the rent the way you did. So start with the exemption itself: the ordinance says an ADU is not a covered unit under the rent stabilization program. Then you can talk about why the city made that choice, which is a separate conversation and a much calmer one.
If you don’t have the ordinance language handy, you can find it through the city’s rent program page. It’s worth printing the relevant section and keeping it in the tenant file. When the question comes up, you’re not arguing from memory. You’re showing them the same text the city would show them if they called.
Why the duplex across the street is capped and your ADU isn’t
The tenant’s comparison is reasonable. A duplex and an ADU can sit on the same block, look similar from the street, and both be rentals. But the ordinance draws the line by building type and ownership, not by appearance. A duplex is a two-unit building on a single lot, and in Concord it’s generally covered by the rent stabilization program unless the owner lives in one unit. An ADU is a secondary unit on a lot with a primary home, and the ordinance exempts it from the rent cap entirely. That’s the structural difference, and it’s the one to name first.
There’s a policy reason behind it, and it’s worth saying plainly. The city wants more ADUs built. Exempting them from rent control is one of the incentives. If an ADU came with the same rent cap as a duplex, fewer owners would build them, and the city’s housing plan depends on those units getting built. That’s not a secret, and you don’t need to defend it. You just need to state it. The tenant may still disagree with the policy, but they can’t reasonably claim you’re misapplying the ordinance.
One thing to be careful about: the exemption applies to the ADU itself, not to the whole property. If you also rent the primary house on the same lot, that house is a separate unit with its own status under the ordinance. Don’t blur the two. The tenant in the ADU is asking about the ADU. Keep the answer there.
What to say when they ask for proof
Here’s a script that works, and you can adjust it to your own voice:
- “The rent stabilization ordinance in Concord exempts accessory dwelling units from the rent cap. Your unit is an ADU under the city’s definition, so the increase I gave you isn’t limited by the same rule that applies to the duplex across the street.”
- “The duplex is a covered unit because it’s a two-unit building and the owner doesn’t live there. If the owner lived in one unit, it would be exempt too. But that’s a different situation from yours.”
- “I can show you the ordinance section if you want to read it yourself. It’s also on the city’s rent program page.”
The third line matters. Offering the source does two things: it signals you’re not hiding anything, and it gives the tenant a way to verify without taking your word for it. Most tenants won’t actually go read the ordinance. But the offer itself changes the tone of the conversation.
If the tenant pushes back on the policy, don’t argue the policy. Say something like: “I understand why it feels unfair, and you’re welcome to contact the city about it. My job is to follow the ordinance as it’s written, and that’s what I’m doing.” Then stop. You’ve answered the question. Anything more sounds defensive.
Where this gets complicated: notice requirements and timing
The exemption doesn’t remove every rule. Even an exempt ADU still has notice requirements for a rent increase, and those are separate from the cap. In California, a rent increase over a certain amount requires a longer notice period, and that applies whether the unit is exempt from rent control or not. Concord may have its own notice rules on top of that. So the tenant’s question about the increase amount is fair, but the timing of your notice is a different compliance question, and it’s one you need to get right on its own.
This is where a lot of landlords trip. They assume the exemption means no rules at all. It doesn’t. It means the rent cap doesn’t apply to the amount. The notice period, the form of the notice, and the way you deliver it are still governed by state and local law. If you get the notice wrong, the tenant can challenge the increase on procedural grounds even if the amount is legal. That’s a worse conversation than the one you’re having now.
We’ve written a separate piece on the Concord ADU rent increase exemptions and notice rules that walks through the notice side in detail. If you’re about to send an increase, read that first. The exemption is only half the equation.
How we handle this in property management
When we manage a Concord ADU, the tenant file includes a copy of the exemption section from the ordinance, the unit’s ADU designation from the city, and the notice history. When a tenant questions an increase, the property manager doesn’t improvise. They pull the file, show the ordinance language, and explain the difference between the ADU and the duplex across the street in about three sentences. Then they offer the source. That’s the whole process, and it works because it’s repeatable.
The reason this matters is consistency. A tenant who gets a clear, sourced answer the first time is less likely to escalate. A tenant who gets a mumbled explanation about “different rules” will call the city, and the city will tell them the same thing you should have said. The only difference is who they trust afterward.
If you manage your own ADU, you can do this yourself. Keep the ordinance language in the file. Know the exemption by name. Offer the source. Don’t argue the policy. That’s the whole skill.
If you’d rather not handle these conversations at all, our property management service in Concord includes rent increase notices, tenant communication, and the documentation that backs up every increase. You don’t have to become an ordinance expert. You just have to know who to call.
What to do before the next increase
Three things, in order. First, confirm your ADU is actually designated as an ADU by the city. If it’s an unpermitted conversion or a unit the city considers part of the primary house, the exemption may not apply the way you think. Second, pull the current ordinance text and read the exemption section yourself. Don’t rely on a summary. Third, check your notice requirements separately from the cap. The amount can be legal and the notice can still be wrong.
If you’re unsure about any of those three, get help before you send the increase. The cost of a consultation is less than the cost of a challenged increase, and it’s certainly less than the cost of a tenant who stops trusting you.
For the broader picture on how Concord’s ordinance treats different building types, our article on Concord rent ordinance exemptions for duplex and single-family covers the other side of the street. It’s worth reading so you can answer the next question before it’s asked.
When you’re ready to talk through your specific situation, reach out here and we’ll walk through it with you.
What’s the hardest part of explaining this to a tenant?
For you, as a landlord: is it the policy argument, the proof, or the fear that you’ll sound evasive? I’m curious what actually trips you up in the moment.
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.
