Concord ADU Rent Increase: The Due-Diligence File to Ask For
Concord ADU rent increase history is the first thing to check when you’re buying a house with an accessory dwelling unit in Concord. The city exempts ADUs from its local rent ordinance, but state law still applies—and most buyers never ask for the paperwork that proves the rent was raised lawfully.
You’re standing in a renovated garage or a backyard cottage, and the listing says it rents for a healthy amount. The seller’s agent hands you a profit-and-loss statement and a lease. What you’re not seeing is whether that rent number has been lawfully increased over the past few years. And if it hasn’t, you’re buying a liability.
The Real Challenge: Two Laws, One Unit
Concord’s rent stabilization ordinance carves out ADUs. As the ordinance stands, a newly constructed ADU is exempt from the city’s rent caps and just-cause eviction rules—check the current text before you rely on it, because these carve-outs can change. But AB 1482, the statewide rent cap law, doesn’t care about Concord’s exemption. It applies to most residential rental properties that are at least fifteen years old, with its own set of exemptions. An ADU built recently might be exempt from AB 1482 too, but an older one—say, a converted garage from the 1990s—could be fully covered.
That’s the trap. Sellers and listing agents often assume the city exemption means no rent control at all. Buyers assume the same. Then the new owner raises the rent, the tenant pushes back, and suddenly there’s a dispute over whether the increase was legal under state law. The time to sort that out is before closing, not after.
What to Ask For: The Rent History File
You need the full rent history for the ADU, not just the current lease. Ask the seller for these documents:
- All leases and amendments for the ADU going back at least three years, or as far as the seller has records.
- Rent increase notices sent to the tenant, with dates and the exact percentage or dollar amount.
- Proof of service for each notice—certified mail receipts, email confirmations, or signed acknowledgments.
- Any exemption notices the seller filed with the city or provided to the tenant under AB 1482 or Concord’s ordinance.
- Bank statements or rent ledgers showing the actual rent collected each month, so you can verify the rent on paper matches the rent paid.
If the seller can’t produce these, that’s a red flag—not necessarily a dealbreaker, but a signal to dig deeper. A missing rent increase notice from two years ago could mean the current rent was never lawfully raised, which caps what you can charge going forward.
Once you have the file, compare each increase against the AB 1482 cap for the year it was issued. The cap changes annually and is tied to inflation, so you’ll need the specific percentage for each year. If any increase exceeded the cap, the rent may be deemed unlawful, and the tenant could be entitled to a refund or a lower base rent. This is exactly the kind of analysis we walk through in our Concord Rent History Verification guide.
Why This Depends on Your Specific Situation
Here’s where it gets nuanced, and why a generic checklist won’t cut it. Whether AB 1482 applies to that ADU depends on several factors: the age of the structure, whether it’s detached or attached, whether the owner lives on the property, and whether the ADU was ever legally permitted. A single-family home with an ADU is treated differently from a duplex with an ADU under both Concord’s ordinance and state law.
For example, Concord’s ordinance exempts single-family homes and condos, but a duplex is covered unless it meets a specific owner-occupancy exemption. An ADU attached to a duplex might fall under the duplex rules, while a detached ADU on the same lot could be treated separately. The interplay is messy, and the city’s forms don’t always make it clear.
That’s why we always recommend pulling the actual ordinance text and, if possible, talking to someone who has worked through these cases locally. Our Concord Rent Ordinance Due Diligence article walks through the key questions to ask, and it’s a good starting point before you make an offer.
How We Walk You Through It
When you’re under contract on a Concord property with an ADU, we can help you build the due-diligence file and make sense of it. Here’s what that looks like in practice:
- Document request: We draft the exact list of documents to request from the seller, tailored to the property type and the ADU’s history.
- Rent history review: We go through every lease, notice, and ledger entry, flagging any increase that looks off against the AB 1482 caps for the relevant years.
- Exemption check: We verify whether the ADU and the main house are exempt from Concord’s ordinance and from AB 1482, based on the current rules and the property’s specifics.
- Risk summary: You get a plain-language summary of what we found, what it means for your purchase price, and what you’d need to do after closing to stay compliant.
This isn’t legal advice—we’re not attorneys—but it’s the operational due diligence that most buyers and even many agents skip. If we find something that needs a legal opinion, we’ll tell you to consult a landlord-tenant attorney before you close.
If you’re looking at a property now, get in touch with our team and we’ll help you put the file together. And if you’re still early in your search, our real estate services page outlines how we support buyers throughout the process.
What Would You Check First?
If you were buying a Concord home with an ADU, would you ask for the rent history before making an offer, or would you trust the listing’s numbers? What’s the one document you’d want to see first?
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.
