The Quick Read: Document a permitted ADU by assembling proof that the unit is legal, proof that it can be rented, and an appraisal that reports its rent as its own line. A permit with a final sign-off is the foundation, and the appraiser’s market rent usually decides the number that counts. Qualification stays subject to lender guidelines.
- Gather the final building permit sign-off and the certificate of occupancy (or the local equivalent).
- Confirm with the building or planning department that the unit is allowed and rentable.
- Expect the appraiser’s rent schedule, not the lease alone, to set the rent used for lender review in many programs.
- Keep a lease and proof of payment ready if the unit is occupied.
- Rent credit is not cash flow. Coverage compares rent to the full housing payment and nothing else.
An accessory dwelling unit can turn a one-rent property into a two-rent property. It can also turn into a paperwork problem. The difference is almost always documentation. This guide walks through how lenders in a wholesale DSCR network treat a permitted ADU, step by step, and where the usual rule breaks.
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What Counts as a Permitted ADU?
A permitted ADU is a separate living unit that the local building department approved, inspected and closed out. It is also smaller than the main house and contributes less value.
Agency material is useful for definitions only. DSCR loans are non-agency products. Across the programs Lendmire places files with, the practical rule is simple: the unit must be legal, and the appraisal must support its rent.
Key Terms Defined
- Permitted: The local authority approved the construction and recorded it.
- Final inspection (final sign-off): The inspector confirmed the work matches the approved plans and closed the permit.
- Certificate of occupancy: The document that says the space is approved for people to live in.
- Legal non-conforming (grandfathered): The unit predates current rules but is recognized as lawful under local law.
- Rent schedule: The appraiser’s report of market rent for the unit, supported by rent comparables.
- PITIA: Principal, interest, taxes, insurance and any association dues. It is the bottom half of the coverage ratio.
Why Legal Status Is the First Gate
Legal status comes first because everything downstream depends on it. If the appraiser flags the unit as unpermitted, it will most likely be left out of both value and rent. Lenders underwrite conservatively. They have to consider a property they might one day operate themselves, and an illegal unit is a liability on that day.
Two things must line up. The unit must be legal, and the rent must be supportable. A permit alone does not finish the job, which surprises many investors.
The Documents That Prove It
Each document proves something different. Here is what to gather and why.
| Document | What it proves | Where to get it | Common snag |
|---|---|---|---|
| Building permit | Work was approved | Building department | Permit still open |
| Final inspection sign-off | Work passed and closed | Building department | Never requested |
| Certificate of occupancy | Unit is approved to live in | Building department | Not issued locally |
| Zoning confirmation | ADU is allowed on the lot | Planning department | Informal verbal answer |
| Plans or as-built drawings | Unit matches what was approved | Seller or owner | Layout changed later |
A permit and a closed permit are not the same thing. Look for the final sign-off. An open or expired permit tells a lender the work may never have been approved.
Some jurisdictions do not issue a separate certificate of occupancy for an ADU. In that case, a finaled permit plus a written confirmation from the planning department is the closest substitute. Ask the department what it considers proof, and get the answer in writing.
How to Verify Status Yourself
You can check most of this before a lender ever sees the file. Work through these five steps.
1. Pull the permit record. The building department keeps a file of permits of record. Many offices have an online portal. Search the address and read the history.
2. Read the status line. Look for final, closed, or completed. Open, expired, withdrawn or canceled means a gap.
3. Ask the three legality questions. Was a permit pulled? Was a certificate of occupancy or final sign-off issued? Does the current footprint match what was approved?
4. Confirm zoning. Ask planning whether the ADU is allowed or recognized as legal non-conforming.
5. Ask about rental permission. A building permit is not automatically permission to rent. Some places require separate registration, and short-term use needs its own local authorization.
Do this early. Picture an appraisal that sits waiting while the city answers legality questions. If the owner already holds the city’s written answers, the appraiser can work from them right away. A ready paper trail prevents that kind of delay.
How the Appraisal Turns Permit Proof Into Rent Credit
The appraiser connects the permit to the rent. Lenders in the network generally want the unit’s rent reported separately from the main house. That means the appraiser needs to know how to classify the property.
A property with one accessory unit may be treated as a single-family home with an ADU, or as a two-unit property. The form follows from that. HUD Mortgagee Letter 2023-17 lists Form 1004 for a one-unit property with an ADU and Form 1025 for two to four units. Fannie Mae‘s ADU income bulletin shows the other common pattern: a Form 1007 rent schedule with the appraiser explaining that the rent is for an ADU. DSCR programs often borrow those form names. They do not borrow the agency eligibility rules.
Appraisers commonly assign less value to ADU square footage than to the main house. That is normal. Do not assume the unit will appraise at build cost.
Here is the sequence that decides whether rent counts:
1. The appraiser confirms legal status from the permit file and local records.
2. The appraiser finds rent comparables for similar units and reports market rent for the ADU.
3. The lender decides whether the program accepts that unit as a countable income line.
4. Rent used for lender review (main house plus ADU, if it counts) is divided by the full PITIA.
Documenting the Rent by Scenario
The rent evidence depends on where the unit stands today.
| ADU status | Proof of legality | Proof of rent | Common snag |
|---|---|---|---|
| Leased now | Final permit, CO | Lease, payment history | Lease rent far from market |
| Vacant | Final permit, CO | Appraiser’s rent comps | Few ADU comps nearby |
| Newly finished | Final sign-off just issued | Appraiser’s rent comps | Record not yet updated |
| Under construction | Not yet final | Not usable yet | Permit still open |
| Short-term use | Final permit plus local approval | Hosting history | Separate local rules |
Many lenders use the appraiser’s market rent rather than the lease. A lease helps, and proof of receipt strengthens it. But the program decides which number controls. Do not assume a higher lease will lift the ratio.
Rent paid by a relative, cash, or a payment app needs a cleaner paper trail than a standard tenant. Keep deposits traceable. If the owner holds title through an LLC, the lease and the deposits should match the entity named on the file, subject to program terms.
Short-term rental on an ADU follows a different lane. Across the network, short-term rental purchases reach up to 75% LTV, and expect a 640+ score and about 12 months of hosting history. Short-term rental rules can vary by city, county, HOA, and property type, so investors should confirm local rules before relying on projected rental income. These specifics are subject to lender guidelines and a full review of property, leverage, and credit.
Supporting Items Underwriters Ask About
Beyond the permit and the rent, a clean file usually answers these questions:
- Utilities and meters: Separate meters are not always required, but the file should show who pays what.
- Address and access: A separate mailing address is often not required. A separate entrance usually matters.
- Insurance: The policy should reflect the real building and its real use.
- HOA, deed and neighborhood restrictions: These can block a separate rental even when the city allows it.
- Rental registration: Some places require it before the unit can be leased.
Gaps here do not usually kill a file. They do slow it down, so collect them before the appraisal is ordered.
Where the General Rule Breaks
The rule is easy to state: legal unit, supported rent, counted income. The edge cases are where files get stuck.
DSCR programs vary on this, so ask the specific program before you assume it works.
Multiple ADUs. A single-family home with more than one ADU is hard to place. One accessory unit is far more common than two. Additional units may need special approval from a select lender, so raise it up front.
An ADU that is too large. A second unit close in size to the main house stops looking subordinate. That can push the file to a different form and a different program.
A bedroom with a kitchenette. This is usually treated as a feature of the house, not a separate unit. It will not earn its own rent line.
An unpermitted unit. It is generally excluded from rent and value. Agency programs sometimes treat illegal units differently. None of that carries over to DSCR. Do not assume that because an agency loan financed an unpermitted unit, a DSCR loan will count its rent. Lendmire’s piece How to Get Rent Credit for an Unpermitted ADU on a DSCR Loan covers that path in detail.
Removing the stove. Pulling the stove and capping the gas line does not assure local authorities would consider the unit legal. It is not a fix.
Amnesty and legalization programs. Some jurisdictions run programs that let owners bring older units into compliance. If yours does, a unit that is unpermitted today may become permitted tomorrow. Check with the local building department.
DSCR vs. conventional financing
There are two common ways to finance an investment property, and they qualify you differently — here’s how investors weigh them.
Why investors choose it
- Qualifies on the property’s rental income — no personal tax returns, W-2s, or pay stubs needed to document income.
- No personal debt-to-income ceiling to clear, so existing mortgages and obligations don’t cap your borrowing the same way.
- Can be closed in an LLC, keeping the property inside a business entity.
- Built for scaling — not held to the limit on number of financed properties that conventional financing applies.
- Underwriting centers on the deal: generally qualifies when the rent covers the payment, a 1.00x coverage ratio being a common baseline (confirmed in underwriting).
- Designed specifically for investment property, including long-term and, where the program allows, short-term rentals.
Where it’s strong
- Often the lowest ongoing financing cost for a buyer who fully qualifies on personal income — a fit for a first property or a cost-first purchase.
Trade-offs for investors
- Requires full personal income documentation and must fit within a debt-to-income limit — salary, existing debts, and other mortgages all count.
- Typically held in your personal name rather than a business entity.
- Caps how many financed properties you can carry, which can become a ceiling as a portfolio grows.
- Evaluates you as a borrower as much as the property, which usually means more paperwork.
How investors usually choose: a first or single property often optimizes for the lowest financing cost; portfolio builders often optimize for leverage, vesting in an LLC, and scaling past conventional caps. The right answer depends on your goals, the property, and current guidelines — both paths run through select lenders in Lendmire’s wholesale network, with eligibility and terms confirmed in underwriting.
What to Do When Documents Are Missing
Missing paperwork does not always mean a dead unit. Work the problem in this order.
1. Ask the department for the permit history. Records are sometimes filed under an old address or a prior owner.
2. If the permit is open, ask what it takes to close it. Often the answer is a final inspection.
3. If no permit exists, ask about legalization. Find out what the local process requires and how long it takes.
4. If neither path works, plan without the rent. Run the ratio on the main house alone.
5. On a purchase, ask the seller for the permit and certificate of occupancy before you write the offer. If neither exists, verify with planning whether the unit is legally recognized.
Permitting takes time, sometimes months for a garage conversion. Build that into the plan. For an investor planning a new build, the usual order is build, final inspection, appraisal with a rent schedule, then a refinance.
The choice to legalize is a real tradeoff. A few investors argue permitting is not worth the cost on a buy-and-hold unit. That view ignores that an unpermitted unit may add no rent credit to the file at all, and it can carry insurance exposure too.
A Worked Example: Two Files
Picture two investors, each with a single-family rental and a detached ADU, each at 75% LTV on a purchase and a similar credit profile above 700. Terms depend on the lender’s guidelines, the property type, the leverage, and a full review of the credit profile.
File A has a finaled permit, a certificate of occupancy and a zoning letter. The appraiser reports rent for the main house and the ADU separately. The combined rent clears roughly 1.25x against the full PITIA. The lender counts both lines.
File B has a permit that was never closed and no certificate of occupancy. The appraiser flags the unit. The lender counts only the main house, and the ratio falls into borderline territory near 1.00. The investor can explore a select-lender path below 1.00 with leverage and terms adjusted, or close the permit and reorder the appraisal. Either path stays subject to lender guidelines, credit approval and property review.
Same house, same ADU, different file. The only variable was paperwork.
Where the Loan Parameters Come In
Coverage is the monthly rent divided by the full housing payment: principal, interest, taxes, insurance and any association dues. Across the network, 1.00 is where many select programs start, and a separate select-lender path takes coverage below 1.00 with leverage and terms adjusted. Stronger ratios open better pricing and leverage.
Purchases typically land at 75% to 80% LTV on an investment property. Cash-out refinances top out around 75% LTV. Credit tiers run from a 620 floor in parts of the network to 660 on most programs and 700 and up for the strongest leverage. Reserves commonly run around 6 months of PITIA, stepping up to about 9 months above $1,500,000. Standard programs reach $3,000,000. Everything varies by lender, property and file.
One caution about the number itself. Clearing 1.00 is not positive cash flow. Repairs, vacancy, management, utilities and capex all sit outside the calculation. ADU rent can lift the ratio, and still leave the investor with thin real-world margins if the unit sits empty. The complete DSCR loans guide walks through how the ratio works across property types.
Packaging the File for the Underwriter
Order matters when a reviewer opens the folder. Put the proof of legality first, then the rent evidence, then the supporting items.
1. A short cover note naming the property, the ADU and the transaction.
2. The permit, final sign-off and certificate of occupancy.
3. The zoning or planning confirmation.
4. The lease, deposits and payment history, if occupied.
5. Insurance showing the unit and its use.
6. Utility and HOA information.
Questions worth asking the broker up front: Does the program count ADU rent from the appraiser or the lease? Does it accept legal non-conforming status? Does it limit the number of units? How does it treat short-term use? Lendmire’s related guide How to Document an ADU So Its Rent Counts on a DSCR Loan goes deeper on the packaging step.
If you are buying or refinancing a rental property and want to see how the numbers work, Lendmire can help you compare DSCR loan options based on the property income, credit profile, leverage, and investor goals.
Frequently Asked Questions
Does my ADU need its own mailing address?
Usually not. The appraiser cares more about whether the unit has a separate entrance, a kitchen, a bathroom and legal status. Some programs may ask about utilities and access, so include that information with the file.
What if my area does not issue a certificate of occupancy?
Ask the building or planning department what it treats as proof of legal occupancy. A finaled permit plus a written confirmation from the department is often the closest substitute. Get the answer in writing so the underwriter can rely on it.
Does a vacant ADU still count?
Yes, it can. The appraiser reports market rent from comparable units, and many programs use that number whether or not the unit is leased. A shortage of nearby ADU comparables is the usual snag, and it can narrow what the appraiser can support.
Can the tenant be a relative?
It is possible, but the file needs a cleaner paper trail. Keep a written lease, traceable deposits and payment history. Some programs rely on the appraiser’s market rent anyway, which reduces the weight of a related-party lease.
What if the permit is still open?
An open permit generally means the work has not been approved, so the unit may not count. Ask the department what is needed for final inspection. Closing the permit before the appraisal is ordered is usually the cleaner route.
About Lendmire
Lendmire is a non-QM mortgage brokerage (NMLS# 2371349) arranging DSCR investor loans in 41 markets, including Washington, D.C., through wholesale and investor-lending channels. DSCR loans are evaluated by the lender on rental income rather than personal income, subject to lender guidelines. They suit LLC-owned portfolios, self-employed investors, and operators scaling beyond conventional loan caps. Recognized as a Scotsman Guide Top Mortgage Workplace in 2025 and 2026.
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References
1. HUD Mortgagee Letter 2023-17
2. Fannie Mae ADU income bulletin
This article is part of Lendmire’s DSCR loan program — full qualification details, guidelines, and scenarios live on the program page.
Related reading: How to Build a DSCR Rent Roll for a Triplex With Mixed Leases · How to Document Gap Money for a DSCR Loan With No Landlord History · How to Finance New Rentals After Consolidating Into One DSCR Loan
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
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- Lendmire LLC · Firm NMLS# 2371349 · Verify firm licensure
Required disclosures. Lendmire (NMLS# 2371349) operates as a licensed mortgage broker, not a direct lender or depository. The discussion in this article is general in nature and should not be relied upon as financial, legal, or tax advice — every investment scenario is unique and should be reviewed by a qualified professional. Any loan inquiry is subject to lender underwriting, and this article is not a commitment to lend or a guarantee of approval. Mortgage rates, loan terms, and program guidelines vary by borrower, property, and state, and may change without notice. Equal Housing Opportunity. Verify licensure at NMLS Consumer Access.