You have a back unit that rents for $1,900 a month. It has a kitchen, a bathroom, and a tenant who pays on time. And you’ve just found out, or always knew, that the city never signed off on it.
Now you want to sell, and every article you read makes it sound like a disaster.
It isn’t. I’ve helped Orange County and LA sellers through this, and the unpermitted unit is rarely what decides how much money you walk away with. What decides it is which of three paths you pick, and how the home is priced and presented to the right buyer.
Here are your three options, the real math on each, and the one I recommend to most sellers.
First: You Are Not in Trouble for Owning It
A lot of sellers are afraid that listing the home will put the unit on the city’s radar and lead to fines.
California changed that. Under AB 2533, which took effect in 2025, the amnesty for unpermitted ADUs and JADUs now covers units built before January 1, 2020. Cities can’t charge impact fees on those units and can’t penalize an owner because an inspection finds the unit doesn’t meet code. They can still require fixes, or deny the permit, if the unit is substandard under the state’s health and safety rules.
You can read the state law itself in Government Code 66331.
Here’s the part sellers miss: that amnesty goes with the property, not with you. Your buyer can use AB 2533 after closing just as easily as you can before listing. That one fact changes the whole decision.
The Example Property
To keep the math honest, let’s use one property for all three options:
- Single-family home in Garden Grove, worth about $1,100,000 as-is
- 450 sq ft garage conversion, 1 bed, 1 bath, unpermitted, built around 2015
- Rents for $1,900/month
- Seller owns it free and clear or has plenty of equity
These are planning numbers for illustration. Your real number depends on your city, your unit, and this month’s comps, which I’ll come back to.
Option 1: Legalize It Under AB 2533, Then Sell
This is what most sellers assume they should do. Get the permit, sell it as a “legal ADU,” and get top dollar.
On paper, it makes sense. In practice, here’s what it costs:
| Cost item | Typical range |
|---|---|
| As-built plans and drafting | $3,000 – $8,000 |
| City plan check and permit fees | $3,000 – $10,000 |
| Electrical, plumbing, and fire safety upgrades | $10,000 – $40,000+ |
| Opening walls for inspection and repair | $2,000 – $10,000 |
| Total (rough) | $18,000 – $68,000+ |
| Timeline | 3 – 9 months |
If the tenant has to move out while walls are open, that’s $1,900 a month you stop collecting. And if your inspector finds something the city calls substandard, the scope grows. I walk through exactly what inspectors look at in AB 2533 explained: Orange County’s inspection checklist.
The math on Option 1
| Amount | |
|---|---|
| Higher sale price as a permitted ADU | +$60,000 |
| Legalization cost (midpoint) | –$40,000 |
| Lost rent (6 months) | –$11,400 |
| Extra commission and closing costs on the higher price | –$3,000 |
| Net gain vs. selling as-is | ≈ +$5,600 |
That’s about $5,600 more, after 6 to 9 months of contractors, inspections, and city emails. And that assumes the market holds while you wait. Right now it isn’t holding. OC buyers finally have leverage with rates over 7%, and in my October Garden Grove ADU market update, the homes priced high are the ones sitting.
A 2% dip in prices on a $1.1 million home is $22,000. That wipes out the entire gain from legalizing, and then some.
When Option 1 does make sense: you plan to keep the property for years and rent it out, the unit only needs minor work, or you’re in a city where permitted ADU comps sell for far more than unpermitted ones. I break down that decision in more depth in AB 2533: I have an unpermitted unit and I plan to sell. Should I legalize it?
For most sellers who want to sell in the next 6 months, legalizing is a lot of work to end up roughly where you started.
Option 2: Disclose It, Price It Right, and Put It on the Market
This is the option I recommend to most of my sellers. It’s simple and fast, and when it’s done well it usually nets the most.
Step 1: Disclose it clearly
California sellers fill out a Transfer Disclosure Statement, and it asks directly about alterations or additions made without permits. Check “yes.” Describe the unit plainly. Hiding it is how sellers end up in court after closing. Disclosing it puts the risk on the buyer, who now knows exactly what they’re buying.
Step 2: Don’t market it as a “legal ADU”
The listing should describe the unit accurately, such as “converted garage with kitchen and bath, not permitted.” Calling it a legal ADU when it isn’t is the fastest way to lose a buyer in escrow, or end up in a lawsuit after.
Step 3: Give buyers a path, not just a problem
This is where the money is made. Most agents disclose the unit and stop there. Buyers see “unpermitted,” get nervous, and either walk or come in with a lowball offer.
The better approach is to hand buyers the answer before they ask:
- The year the unit was built, with any proof you have (photos, receipts, old listings). This shows it qualifies for AB 2533’s pre-2020 cutoff.
- A short note on how cities can’t deny a permit for an unpermitted ADU built before 2020 just because it doesn’t meet current code.
- The current lease and rent history, so the buyer can see what the unit earns compared to other OC ADUs.
- A clear record of everything that’s known, so there are no surprises when they review the documents a buyer requests on an already-built ADU.
When a buyer can see that they can legalize it themselves, under the same law you would have used, the unit stops being a red flag and becomes an opportunity they’re willing to pay for. Smart buyers are already running this exact math. I wrote about it for them in Buying a House With an Unpermitted ADU? AB 2533 Changes the Math.
Step 4: Price for the buyer who wants the unit
Your best buyer is not a family who’ll turn the unit into a home gym. It’s an investor or a multigenerational buyer who wants that second unit and plans to legalize it. The price, the photos, and the listing copy should all be aimed at that buyer.
The math on Option 2
| Amount | |
|---|---|
| Sale price (disclosed, unpermitted) | $1,100,000 |
| Commission and closing costs (~5%) | –$55,000 |
| Legalization cost | $0 |
| Lost rent | $0, tenant stays and pays through escrow |
| Estimated net | ≈ $1,045,000 |
| Timeline | List now, typically close in 45 – 75 days |
You skip the contractors, the city, and the 6-month wait. You sell into today’s market, not one you have to guess about next spring.
If you have a tenant in the unit, you have choices there too. See whether to wait for your tenant to move out before listing and how selling with an active tenant works in Orange County.
Option 3: Sell As-Is to a Cash Investor
You’ve seen the postcards: “We buy houses, any condition, close in 7 days.” For an unpermitted unit, that can sound like relief.
It’s fast. You skip repairs, showings, and most of the uncertainty. But you pay for that speed. Cash investors need room for their own legalization costs, holding costs, and profit, so offers usually come in well below market.
The math on Option 3
| Amount | |
|---|---|
| Cash offer (≈ 10% – 20% below market) | $880,000 – $990,000 |
| Closing costs (often reduced, no listing commission) | –$10,000 |
| Estimated net | ≈ $870,000 – $980,000 |
| Timeline | 7 – 30 days |
Compared to Option 2, that’s $65,000 to $175,000 less in your pocket.
When Option 3 does make sense: the unit has serious safety problems, the main house needs major repairs too, you’re dealing with a probate or divorce on a tight deadline, or you need cash in under 30 days. Even then, the smart move is to let the open market compete for it. A properly marketed listing often draws the same cash investors, but now they’re bidding against each other instead of sending you a take-it-or-leave-it offer.
Side-by-Side: All 3 Options
| Option 1: Legalize | Option 2: Disclose and list | Option 3: Cash investor | |
|---|---|---|---|
| Estimated net | ≈ $1,050,600 | ≈ $1,045,000 | ≈ $870,000 – $980,000 |
| Time to closed sale | 6 – 12 months | 2 – 3 months | 1 month or less |
| Out-of-pocket cash | $18,000 – $68,000+ | $0 | $0 |
| Risk | Scope creep, market shifts | Pricing and buyer fit | Leaving money on the table |
| Best for | Long-term holders | Most sellers | Distressed or urgent sales |
Options 1 and 2 land within a few thousand dollars of each other. One takes most of a year and up to $68,000 of your own money. The other takes a listing agreement.
What About Converting It Back to a Garage?
Some sellers ask about tearing out the kitchen and turning it back into a garage. You’ll spend money to remove the one feature your best buyers would pay extra for. Unless the city has already cited you and requires it, this usually loses money.
The Number You Can’t Get From an Article
Everything above uses one example property. Your real decision depends on three numbers that change by city and by month:
- What permitted ADU homes are actually selling for on your street compared to homes with unpermitted units
- What your specific unit would cost to legalize, based on its age, size, and condition
- Who is buying in your city right now, whether investors, house hackers, or multigenerational families, and what they’ll pay for a second unit
A typical listing agent will look at the unpermitted unit and either ignore it or knock it down to “storage.” That’s how sellers lose $50,000 or more without knowing it. It’s one of the big differences between an ADU Realtor and a typical agent. I price and market the unit to the buyers who want it.
On a 15-minute call, I’ll pull your city’s recent ADU sales and show you your three net numbers side by side. No pressure to list. You’ll know which option leaves the most money in your pocket before you spend a dollar on permits. For the full selling process, see my complete guide to selling a home with an ADU.
Frequently Asked Questions
Can I sell a house with an unpermitted ADU in California?
Yes. It’s legal to sell a home with an unpermitted ADU as long as you disclose it on the Transfer Disclosure Statement. Many buyers, especially investors, actively look for these properties.
Do I have to legalize an unpermitted ADU before selling?
No. California doesn’t require it. Under AB 2533, units built before January 1, 2020 can be legalized by the next owner too, so many sellers disclose the unit and let the buyer handle permits.
Will listing my home get me fined for the unpermitted unit?
For units built before 2020, AB 2533 generally bars cities from charging impact fees or penalizing the owner when an inspection finds the unit doesn’t meet code. A city can still require fixes for real health and safety problems.
How much does an unpermitted ADU lower my home’s value?
It depends on the city and the unit. Many buyers pay less for an unpermitted unit than a permitted one, but the gap is often close to what legalizing would cost. That’s why legalizing before selling usually doesn’t add much equity.
Should I sell to a cash investor because my ADU isn’t permitted?
Only if you need speed or the property has serious problems. Cash offers typically come in 10% to 20% below market. A well-marketed listing often draws those same investors, competing against each other.
Can I advertise an unpermitted unit as an ADU?
Describe it accurately, such as “converted garage with kitchen and bath, not permitted.” Don’t call it a legal or permitted ADU.
This article is general information, not legal or tax advice. Talk to a real estate attorney about your specific disclosure obligations.
Find Out Which Option Nets You the Most
Book a call with Dylan, The ADU Realtor. I’ll run all three numbers on your property, using real ADU sales from your city, so you can decide with the math in front of you. Then you can choose to list, legalize, or hold.
Book a Seller Consult call with NO OBLIGATIONS: https://calendar.app.google/EQdtXnrrVFCdNUsT6
