The Quick Read: An ADU’s income counts only when the unit is legal, supported by the appraisal, and allowed under the program’s short-term-rental rules, and the lender then trims projected Airbnb revenue before dividing by the full monthly payment, so the headline revenue a first-time host expects is never the number that qualifies.
- Four gates decide the outcome: legal status, appraisal support, program rules, and the income method.
- A first-time host has no booking history. Income usually rests on a market projection or on long-term market rent, depending on the lender.
- On short-term-rental files across the wholesale network, purchase leverage tops out at 75% LTV, and refinance and cash-out top out at 70% LTV on STR collateral, with a 640 minimum score, all subject to lender guidelines.
- Clearing the coverage floor does not mean the property cash-flows.
What Does “ADU Income” Mean to a Lender?
Lenders separate income you collect from income that qualifies. An accessory dwelling unit (ADU) can bring in real rent or real nightly revenue and still add nothing to the coverage ratio. The unit has to pass several checks first.
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Short-term rental income is documented with a 12-month history or a market data report. Program parameters update from Lendmire’s centralized guideline source.
As of Oct 15, 2026 · General Freddie Mac market benchmark, not a Lendmire loan offer. Nightly rate, occupancy, taxes, and insurance are editable estimates. Qualifying income for short-term rentals varies by program — some use appraisal market rent, others use documented STR history or projections — and is confirmed in underwriting. Not a Loan Estimate, approval, or commitment to lend. Program availability and eligibility are subject to lender guidelines, credit approval, property review, and underwriting.
DSCR loans are business-purpose loans for non-owner-occupied rental property. Because the file qualifies primarily on property-level rental income covering the payment, subject to lender guidelines, the question becomes which rental income the lender will recognize. There is no single rule that says ADU income counts at a set percentage. Each program sets its own method.
ADU lending has long been harder than it looks. The Appraisal Journal’s study of properties with accessory dwelling units found that appraisals and loans on these properties can be complicated by inaccurate perceptions and institutional policies. It also noted that unpermitted ADUs are often the only kind local brokers and lenders know about. That article is dated, so read it as background. The pattern still shows up on files today.
The Four Gates ADU Income Must Pass
Every ADU file runs through the same four gates, in this order. Fail one and the income drops out of the ratio.
1. Legal status. Is the unit permitted and recognized as a dwelling? Unpermitted units generally get little or no credit.
2. Appraisal support. Can the appraiser find comparable properties and a defensible rent figure for the unit?
3. Program rules. Does the lender’s program accept this unit type, this rental use, and this income method for a host with no history?
4. Income method. Is the income a lease, an appraiser’s market rent, or a market-data projection, and what trim applies?
The third gate is where Lendmire’s position as a broker matters. Across the wholesale network it places files with, the same ADU can clear the gates at one lender and stall at another. Comparing programs before the appraisal is ordered is usually cheaper than finding out afterward.
How a DSCR Lender Counts ADU Income, Step by Step
The sequence below is how underwriting typically treats a house with an ADU. Details shift by program.
Step 1: Classify the property. A single-family home with a small ADU is usually treated as a one-unit property, and the appraiser documents rent on Form 1007. Fannie Mae’s appraiser update describes Form 1007 as the single-family comparable rent schedule for an investment property. If the second unit is large enough to read as a separate unit, the file looks more like a duplex, and the rent analysis moves to Form 1025, the 2-4 unit equivalent. These are appraisal forms, not DSCR rules. DSCR programs borrow the vocabulary only.
Step 2: Confirm legal status. The lender wants proof the ADU is permitted and insurable. An unpermitted unit may get no credit at all, and legalizing it may have to come first.
Step 3: Decide the rental use. A first-time host can price the ADU as a long-term rental or as an Airbnb. A lease or the appraiser’s market rent supports the first. The second needs hosting history or a market projection.
Step 4: Pick the income evidence. More on the three routes in the next section.
Step 5: Apply the expense factor. On short-term income, lenders commonly trim gross revenue before using it. The trim varies by lender, and some experienced hosts see little or none. It applies to the income side only. The payment stays whole.
Step 6: Run the ratio. Qualifying monthly income divided by the full monthly obligation: principal, interest, taxes, insurance, and any HOA dues. Whether the ADU income is added to the main home’s rent or counted alone depends on how the unit is configured and what the program allows.
Step 7: Underwriter review. The lender reviews credit, reserves, property condition, and the appraisal. Reserves vary by lender, leverage, loan size, and transaction type. Around 6 months of PITIA is common, and larger loans typically step up.
Why the Appraiser Does Not Settle the Income Question
The appraiser values real estate. McKissock, a provider of appraiser education, explains that Form 1007 documents monthly rent, that furnishings and business income are excluded from the real-estate valuation, and that the lender makes the final call on income. The Fannie Mae update adds that the form was not designed for nightly rentals. It also calls a nightly rate multiplied by 30 an incorrect way to produce monthly rent.
For a first-time host, that means the appraisal gives you a long-term rent number and a collateral value. It does not prove what the Airbnb will earn. Any larger number has to come from somewhere else.
Three Ways a First-Time Host Can Document Income
A true first-timer has no platform history. These are the routes lenders use, and what each means for you.
| Route | What it is | Risk for a first-timer |
|---|---|---|
| Platform history | Trailing booking statements | Does not exist yet |
| Market projection | Data-based earnings forecast | Program may not accept it |
| Long-term rent | Appraiser’s rent schedule | Often below STR potential |
Market-data tools can estimate earning potential from nearby comparable listings. Whether a lender accepts that estimate for a host with no record is decided program by program. Short-term-rental programs also usually expect about 12 months of landlord or host experience, so a first-timer should ask early how the program treats someone without it.
If no short-term route works, the ADU may fall back to long-term market rent. That is usually a lower, more reliable figure. Lendmire’s complete DSCR loans guide covers the basic ratio and program structure in more depth. For the whole-house version of this question, see Lendmire’s how a DSCR lender counts Airbnb income for a first-time STR buyer.
A Worked Example: House Plus ADU
Here is a modeled scenario. The inputs are assumptions, not market data. Dollars are left out on purpose, so everything is expressed as coverage of the full monthly payment.
Assume the main house, rented long-term, covers about 0.95x of the full payment on its own. The ADU, projected as an Airbnb, shows gross revenue worth about 0.55x of that same payment. Apply a modeled 20% expense factor and the ADU contributes about 0.44x. Combined coverage lands near 1.39x.
Now change one input at a time:
- Program accepts only long-term rent for the ADU. Assume the unit adds about 0.30x. Combined coverage lands near 1.25x.
- ADU excluded entirely because it is unpermitted. Coverage stays at about 0.95x.
That last line is the instructive one. Below 1.00, the file is no longer in standard territory. Coverage below 1.00 is available through select lenders in the network, with leverage and terms adjusted. Qualification stays subject to lender guidelines, credit approval, and property review.
The same math explains why 1.00 matters. It is where select programs start, and stronger ratios open better terms and leverage. It is not a promise of approval.
Where the General Rule Breaks
Most ADU files follow the gates above. These edge cases bend them.
Thin comparables. Market projections get weaker where few similar short-term listings exist. A lender may discount the figure more, or fall back to long-term rent.
The 1007 gap. The rent schedule often comes in well below short-term potential. A property that clears 1.00 on Airbnb income can miss it if the program defaults to long-term rent.
Short-term-rental legality. 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. An HOA minimum-stay rule, for example, can put the property back in long-term territory.
Detached versus attached units. Whether a lender treats a garage conversion, a basement unit, and a backyard cottage the same way depends on the program. The same goes for separate utilities and for more than one ADU. Ask before you assume.
Ineligible structures. Manufactured homes, log homes, and barndominiums are not offered in these DSCR programs. A unit built in one of those styles does not become eligible by being an ADU.
Conventional contrast. Agency-style loans underwrite on personal income, and short-term income there is its own subject. DSCR is not the same rulebook, and borrowers should not carry assumptions from one to the other.
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.
Why ADU Income Gets Excluded, and What Fixes It
| Cause | Typical fix |
|---|---|
| Unit not permitted | Legalize before the loan |
| No comparable properties | Ask lender for another method |
| Program rejects projections | Try a program that accepts them |
| HOA or local STR limit | Price as long-term rent |
| Host has no record | Use long-term rent basis |
Most of these are fixable. The costly mistake is learning about them after ordering an appraisal. A quick conversation with a broker about which programs accept your unit saves an appraisal fee.
Count the ADU, or Treat It as Upside?
Run every ADU deal twice, once with the income and once without. If the file works without it, the ADU is upside. If the file only works with it, the ADU is carrying the loan, and any change in the gates puts the deal at risk.
This is a real tradeoff. A long-term lease on the ADU is easier to document, so it is often the safer way to clear the ratio. A short-term plan may produce higher gross revenue, but the lender trims it, and a first-timer has a harder time proving it. Investors who plan to host anyway can still qualify on the conservative number and let the Airbnb performance be the cushion.
Leverage is the other half of the decision. On a short-term-rental purchase, leverage tops out at 75% LTV on the strongest files. On an STR refinance or cash-out, the ceiling is 70% LTV on STR collateral. A minimum score of 640 is typical for these programs, and loan sizes run up to $3,000,000 on standard programs. All of these ranges are subject to lender guidelines. Coverage floors are 1.00 on STR purchases and 1.00 on STR refinances.
If you instead use a long-term-rent basis on a standard investment-property purchase, most files land at 75% to 80% LTV. A larger down payment can lift the ratio by lowering the payment, but it never erases leverage caps, credit floors, or reserve rules. And clearing 1.00 is not positive cash flow. Repairs, vacancy, management, utilities, and capital reserves all sit outside the calculation. Tax treatment varies; consult a qualified tax professional about how hosting income is reported.
For a related view on sizing projected nightly revenue, see Lendmire’s piece How a First-Time STR Buyer’s Airbnb Income Is Sized for DSCR.
Key Terms Defined
ADU (accessory dwelling unit): A secondary, self-contained living space on the same lot as a main home, such as a garage conversion or backyard cottage.
PITIA: The full monthly obligation of principal, interest, taxes, insurance, and any HOA dues.
Qualifying income: The rental income a lender agrees to count, which can differ from the rent or revenue you actually collect.
Expense factor (haircut): The percentage a lender trims from gross short-term revenue before using it in the ratio.
Form 1007 / Form 1025: Appraisal forms that document market rent on a single-family property and on a 2-4 unit property, respectively.
Coverage ratio: Qualifying monthly income divided by PITIA. It is the core test in a DSCR file.
Frequently Asked Questions
Can an unpermitted ADU’s income count toward DSCR?
Usually not. Unpermitted units generally receive little or no credit in the appraisal, and lenders tend to exclude their income. The practical route is to legalize the unit first, or to qualify the file on the main home alone and treat the ADU as upside.
Can a first-time host qualify with no Airbnb history?
It depends on the program. Some lenders in the network accept a market-data projection, and others fall back to long-term market rent. Short-term programs usually expect about 12 months of host experience, so ask before you commit to a property. Qualification stays subject to lender guidelines and credit approval.
Does the appraiser’s rent figure set my qualifying income?
It often sets the long-term rent figure, but the lender decides which income counts. The appraiser values the real estate and excludes furnishings and business income. If the appraisal lands low, the lender may use a different method, or may not.
Is a vacant or brand-new ADU counted differently from one already rented?
Often yes. An existing lease or trailing history is stronger evidence than a projection. A vacant or new unit usually leans on the appraiser’s market rent or a market estimate, and how much credit it gets depends on the program.
Does clearing the coverage floor mean the property makes money?
No. The ratio compares rent to PITIA only. Vacancy, repairs, management, and utilities sit outside it, so a property can clear 1.00 and still run thin on cash flow.
Running Your Own ADU Numbers
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. As a mortgage broker arranging DSCR financing through select lenders across 41 markets, including Washington, D.C., Lendmire can show how the same ADU is treated across programs before you order an appraisal.
About Lendmire
Lendmire — NMLS# 2371349 — is a DSCR and non-QM mortgage brokerage with investor loan programs in 41 markets, including Washington, D.C. DSCR eligibility is commonly reviewed by the lender around property-level rent rather than personal income documentation, subject to lender guidelines, and the brokerage helps arrange financing for LLC-owned portfolios beyond conventional financed-property limits. Recognized by Scotsman Guide as a Top Mortgage Workplace in 2025 and 2026.
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References
1. The Appraisal Journal, Understanding and Appraising Properties with Accessory Dwelling Units
2. Fannie Mae, Appraiser Update June 2024
3. McKissock, Form 1007 and Short-Term Rental Appraisals
This article is part of Lendmire’s short-term rental loan program — full qualification details, guidelines, and scenarios live on the program page.
Related reading: How to Document a Lease to a Relative so a DSCR Lender Counts It · Lease vs Appraiser Rent on a DSCR Loan for a First-Time Landlord · How to Raise a Thin DSCR Before the Lender Runs the Numbers
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
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Important disclosures. Lendmire (NMLS# 2371349) is a licensed mortgage brokerage. Lendmire is not a direct lender, depository institution, or financial advisor. All loan inquiries are subject to lender underwriting; this article does not constitute a commitment to lend. Rates, terms, and program guidelines are subject to change without notice and vary by borrower profile, property type, and state. Information in this article is general in nature and is not financial, legal, or tax advice. Equal Housing Opportunity. NMLS Consumer Access: nmlsconsumeraccess.org.