Step 3 of my buyer process is the Escrow Zone. Once your offer is accepted, we use the contingency period to do two jobs at the same time: due diligence on the house, and an ADU feasibility study on the lot. I connect you with an ADU contractor and their architect, and we meet over a screen-share call where they lay possible ADU layouts right on top of your parcel. You see where the unit goes, how big it can be, what it should cost and what it should rent for, all before your contingencies end and your deposit is at risk.
Most buyers find out what they can build after they close. This step moves that answer up to the window where you can still renegotiate or walk away.
Last updated: October 2026. Dylan Serna, The ADU Realtor.
The Escrow Zone at a Glance
| When it happens | From accepted offer until you remove contingencies (often 17 days in a standard California purchase agreement) |
| What we check | The house (inspections, permits, title, appraisal) and the lot (ADU size, placement, utilities, cost, rent) |
| Who’s involved | You, me, your inspector, your lender, and an ADU contractor with their architect |
| How the ADU meeting works | A video call with screen share. The architect shows layouts drawn over your actual parcel |
| What you leave with | An ADU feasibility report: layout options, estimated build cost, projected rent and any red flags |
| The decision | Remove contingencies, renegotiate, or cancel with your deposit protected |
Where Step 3 Fits in the Process
By the time you’re in escrow, the first two steps have already done a lot of the filtering. In Step 1, the ADU Vision Session, we set your goal, all-in budget, cities and lot criteria. In Step 2, Exploratory Tours, we toured corner lots, RV-access lots and alley homes, and you got a booklet for each property with projected house rent, ADU rent and estimated build cost. Then we wrote the offer.
Those booklet numbers are estimates based on the four things I look for in a lot with ADU potential. Step 3 replaces estimates with a professional opinion on this specific parcel. The full three-step overview is in how I help buyers find properties with ADU potential.
A Typical Escrow Timeline
Every contract is different, but here’s how the 17 days usually play out on an ADU purchase:
| Days | House due diligence | ADU feasibility |
|---|---|---|
| 1–3 | Earnest money deposit, order inspections, review seller disclosures | I send the contractor the address, parcel info and listing photos |
| 3–7 | General home inspection, sewer scope, roof and termite | Architect pulls the parcel map, zoning and setbacks |
| 5–10 | Preliminary title report, permit history from the city | Screen-share feasibility meeting with you, me, the contractor and architect |
| 7–14 | Appraisal, loan underwriting | Feasibility report delivered with layout options and cost range |
| 14–17 | Request repairs or credits if needed | We re-run your numbers with the real build cost |
| 17 | Decision: remove contingencies, renegotiate, or cancel | |
For the city-by-city version of the paperwork side, see my escrow ADU verification checklist.
Part 1: Due Diligence on the House
An ADU investment is still a house purchase first. If the main house has a $40,000 problem, that’s $40,000 that isn’t going into the ADU. Here’s what we check.
Inspections
- General home inspection: roof, plumbing, foundation, HVAC and the electrical panel
- Sewer scope: a camera down the sewer line. Older OC and Long Beach homes often have clay lines, and the ADU will likely tie into the same lateral
- Electrical panel size: many 1950s and 1960s homes have 100-amp service. Adding an ADU usually means upgrading the panel, and sometimes the utility service
- Termite and roof: standard, but worth having so repair credits are on the table
Permits and records
We pull the permit history from the city and compare it to what’s actually on the property. A converted garage or a back unit with no permits changes both the value and the plan. If you run into that, read buying a house with unpermitted work in California. If the property already has an ADU, the list of what to request is in what documents to get during escrow on an already-built ADU property.
Title, appraisal and tenants
The preliminary title report shows easements. A utility easement running across the back of the lot can block the spot where an ADU would go, so the architect gets a copy. The appraisal confirms the price works for your lender. And if the home is occupied, we verify leases and deposits using the steps in rent roll and estoppels before you buy a property with tenants.
Part 2: The ADU Feasibility Meeting
This is the part most buyers never get before closing. I connect you with an ADU contractor I trust and the architect they work with. Before the meeting, the architect pulls your parcel map, zoning and setbacks. Then we all get on a video call.
Why we do it on a screen share
You don’t have to drive to an office or wait for a site visit. The architect shares their screen and drops ADU footprints onto an aerial view of your lot. You watch the unit move around the backyard in real time: next to the garage, behind the house, along the alley. You can ask “what if it’s a two-bedroom?” and see the answer in a few minutes. Most buyers are working full time during escrow, so a 45-minute call fits in a lunch break.
What the architect shows you
- The buildable area: where a unit can legally go once setbacks are applied. State law caps side and rear setbacks for most ADUs at 4 feet, per the HCD ADU Handbook
- Layout options: usually two or three, such as a 1-bed, a 2-bed and a garage conversion
- Placement and access: where the tenant enters, where they park, and how far the unit sits from the main house
- Utility runs: how far sewer, water and power need to travel. Longer runs cost more
- One story or two: on smaller lots, going up can save yard space. Tradeoffs are in two-story vs. single-story ADU
The contractor then puts a cost range on each option. That’s why I bring both into the same meeting: the architect tells you what fits, and the contractor tells you what it costs to build. If you want to vet the contractor yourself, use my 10-point ADU contractor checklist and look up their license on the CSLB license check.
Example: three layouts on one lot
Here’s what a feasibility meeting might show on a 6,500 sq ft lot with a detached two-car garage in north Orange County:
| Option | Size | Est. build cost | Est. ADU rent |
|---|---|---|---|
| Garage conversion, 1-bed | About 440 sq ft | $120,000–$150,000 | $2,000–$2,200 |
| Detached 1-bed | About 600 sq ft | $200,000–$230,000 | $2,200–$2,400 |
| Detached 2-bed | About 800 sq ft | $260,000–$290,000 | $2,700–$2,900 |
Example ranges only. Your contractor prices your lot. Rent ranges come from the comp method in how to find rents for an ADU you haven’t built yet.
One detail that often comes up: an ADU under 750 sq ft is exempt from city impact fees under state law, and larger units pay fees in proportion to the main house. That can tilt the decision between a 1-bed and a 2-bed. More on size tradeoffs in the best ADU layout for your Orange County lot size.
What’s in the ADU Feasibility Report
After the meeting, the contractor’s team sends a short report you can keep and share with your lender or partner. It usually includes:
- Site plan sketches for each layout, with setbacks marked
- Maximum ADU size the lot allows under the city’s rules and state law
- Estimated build cost range for each option, including design and permit fees
- Utility notes: panel upgrade, sewer connection, water meter
- Red flags such as easements, slope, protected trees or fire access
- An estimated timeline from design to permit to move-in
Red Flags That Change the Deal
The point of doing this in escrow is leverage. Here’s what we do when something comes up:
| What we find | Why it matters | What we usually do |
|---|---|---|
| Cracked or root-filled sewer line | The ADU ties into it; replacement can run $8,000–$20,000 | Ask for a credit or a price reduction |
| 100-amp electrical panel | Most ADUs need a panel upgrade, sometimes a utility service upgrade | Build it into the budget or ask for a credit |
| Easement across the backyard | Can block the best ADU location | Architect tests other placements; if none work, we reconsider |
| Unpermitted structure where the ADU would go | May need to be legalized or removed first | Price in demo or legalization costs |
| Build cost well above the booklet estimate | Cash flow drops, cash needed goes up | Renegotiate or cancel |
A pool in the backyard is another one that comes up a lot. I cover it in what to know when an ADU-potential property has a pool. And it’s the reason I tell buyers never to fully trust “ADU potential” in a listing until a professional has looked at the lot.
Re-Running Your Numbers Before You Commit
Once we have real build costs, we re-run the same simple math from your Vision Session: total monthly payment against total rent. Here’s the example property from that session, a $1,050,000 home with 50% down, under each layout:
| 600 sq ft 1-bed | 800 sq ft 2-bed | 1,000 sq ft 3-bed | |
|---|---|---|---|
| Build cost (paid in cash) | $220,000 | $275,000 | $330,000 |
| Cash in (down payment + build) | $745,000 | $800,000 | $855,000 |
| Monthly payment (PITI) | About $5,180 | About $5,230 | About $5,280 |
| Total rent (house $4,100 + ADU) | $6,400 | $6,900 | $7,400 |
| Rent minus payment | About +$1,220 | About +$1,670 | About +$2,120 |
Assumes a $525,000 loan at 7.75% for 30 years, property tax at 1.15% of price plus build, and $200 a month insurance. Before vacancy, repairs and management.
The bigger unit costs more cash but adds more rent than payment. Whether that’s the right call depends on how much cash you want tied up. For the full cost picture from deposit to first rent check, see what it really costs to buy a home and add an ADU in Orange County.
Your Three Choices at the End of Escrow
- Remove contingencies and move forward. The lot works, the numbers work, and you close knowing what you’re going to build.
- Renegotiate. We use the inspection and feasibility findings to ask for a price reduction or a credit.
- Cancel. If the ADU doesn’t fit or the numbers don’t hold up, you cancel inside the contingency period and your deposit is protected.
Walking away isn’t a failure. It’s what Step 3 is for. Spending a few weeks to avoid the wrong lot is a much better outcome than closing and finding out later.
After You Close
Because the feasibility work is done, your contractor can start design right after closing instead of starting from zero. State law requires cities to approve or deny a complete ADU permit application within 60 days, per California HCD. If you use a city’s pre-approved ADU plan, AB 1332 shortens that to 30 days for a detached unit. The full build sequence is in the ADU construction process, step by step.
I run this process for buyers in Anaheim, Garden Grove, Santa Ana, Orange, Costa Mesa and Long Beach, among other cities in Orange County and LA County. Each city has its own ADU rules, and the architect checks them for your lot.
Frequently Asked Questions
What is an ADU feasibility study?
It’s a review of a specific lot by an architect and contractor to confirm what size ADU fits, where it can go, what it will cost and any issues that could block it. In my process, it happens during escrow so you have the answer before you commit.
Can I do an ADU feasibility study while in escrow?
Yes. That’s the best time to do it. Your investigation contingency gives you time to study the property and cancel if it doesn’t work. We schedule the feasibility meeting in the first week or so of escrow.
Do I have to meet the architect in person?
No. We do it over a video call with screen share. The architect shows the layouts on your parcel, and you can ask for changes during the call.
Am I required to hire the contractor I meet?
No. The meeting gives you a clear plan and a cost range. You’re free to get other bids after you close.
What if the property already has an ADU?
Then Step 3 focuses on confirming the ADU is permitted, checking its condition and verifying the lease. If it’s unpermitted, it still adds value, just less than a permitted unit, and we look at the cost to legalize it before you remove contingencies.
Start With a Vision Session
Step 3 works because Steps 1 and 2 got you to the right lot. If you’re planning to buy an investment property in Orange County or LA County and add an ADU, let’s set your plan first.
👉 Book a buyer ADU consult call to go through your options with Dylan
Want to see what’s on the market now? Browse current ADU homes for sale or read the multifamily ADU buying guide.
Prefer to talk now? Call Dylan Serna, ADU Realtor at 714-860-2868.
Dylan Serna | The ADU Realtor | eXp Realty | DRE #02217359
This post is general information, not legal, tax or financial advice. Contingency periods depend on your contract. Cost, rent and payment figures are examples; confirm numbers and ADU rules for any specific property before you buy.
