The Quick Read: It depends on whether the casita is a legal, rentable unit that the appraisal supports, because rent you collect on an unpermitted or unsupported structure usually does not count toward either value or coverage. When the casita does count, it can help in two separate ways: more appraised value and more rent used for lender review. Both effects run through the appraiser and the lender, not through your bank deposits.
- A legal casita may support a higher appraised value, depending on comps and underwriter review.
- Rent used for lender review usually comes from the appraisal’s market rent or the lease, whichever is lower, not from what you actually collect.
- Cash-out on a standard investment rental tops out around 75% LTV, with about 6 months of seasoning as the common expectation.
- An unpermitted or unsupported casita is typically left out, and the file proceeds on the main house alone.
- Clearing 1.00 coverage is not the same as positive cash flow.
This is written for investors who already own a rental with a casita, guest house, or similar detached structure on the lot. It covers how the numbers get built, where files stall, and what to settle before you order an appraisal.
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Why Detached Casita Rent Raises Two Different Numbers
A casita can affect your cash-out refinance in two ways, and they work independently. One is value. The other is rent coverage. Keep them apart in your head, because one can work while the other fails.
Start with the basics. A cash-out refinance replaces your current loan with a larger one and hands you the difference. The loan size is capped by the property’s appraised value times the maximum LTV. LTV, or loan-to-value, is the loan balance divided by the appraised value. Across most of the wholesale network Lendmire works with, a cash-out on an investment property tops out around 75% LTV, subject to lender guidelines.
The value effect. The appraiser decides what the whole property is worth. If the casita is a legal, finished structure that buyers pay for, the opinion of value may reflect it. If it is not, the appraiser may give it little or no credit. A bigger appraised value lifts the maximum loan. Your payoff stays the same, so the cash back grows by a bigger percentage than the value gain.
The rent effect. DSCR stands for debt service coverage ratio. It compares the property’s qualifying monthly rent to its full monthly obligation: principal, interest, taxes, insurance, and any HOA dues. Lenders call that obligation PITIA. When the casita’s rent is allowed into the numerator, coverage improves. That matters most when the main house alone sits near the floor.
A casita that fails the legality test fails both tests at once. That is the most common surprise on these files.
What Makes a Casita Count?
A casita counts when it is a legal, separately rentable dwelling and the appraiser documents it that way. Lenders underwrite to how the property would perform if they had to take it back and operate it. A structure that could not legally be rented in that scenario does not earn credit.
Fannie Mae’s published material gives a useful plain-English picture of what an accessory dwelling unit is. Fannie Mae’s ADU income scenarios describe it as an independent living area with living, sleeping, cooking, and bathroom facilities on the same parcel. It can be attached, created inside the house, or detached. That is an agency definition used for contrast only. DSCR lenders write their own rules, and the wholesale network treats each file individually.
In practice, the same few things sink a casita:
- No kitchen. A bedroom with a kitchenette often does not read as a separately rentable unit.
- Wrong permit. A detached structure permitted only for storage, an office, or recreation is not a permitted dwelling.
- Prior informal rental. A previous owner may have rented it without every approval, and that history does not make it legal.
- Separate parcel. A structure on its own parcel is a different analysis from a casita on the same lot.
If you cannot show the unit is legal, assume the underwriter will treat it as a nice-to-have amenity, not income. The usual workaround is to refinance on the main house alone.
How Is the Casita Appraised?
The appraiser reports value and market rent as two separate opinions. For a one-unit property with a casita, the appraisal typically comes with Form 1007, the single-family comparable rent schedule. A property legally classified as 2-4 units uses Form 1025, which reports rent per unit.
The classification matters because it changes what the rent number represents. On a one-unit property, the rent schedule may estimate the main house with a separate line for the casita. On a legal duplex, each unit is reported on its own.
Appraisers can build the value opinion several ways. The income approach values income property as net operating income divided by a cap rate, as this McKissock explainer on the income approach lays out. For a house with a casita, sales comparisons usually carry more weight than the income approach. An appraiser may also add the casita’s contributory value using cost or a rent multiplier. Methods differ by appraiser and property.
Scarce comps are a real issue. Few true casita rentals exist in many areas, so the appraiser may lean on small apartments or individual units from multi-unit buildings. That can produce a lower or contested rent figure. If you have documented leases on comparable casitas nearby, hand them to the appraiser through your lender. Do not expect them to be adopted automatically.
Which Rent Number Does the Lender Use?
Most programs we place files with compare the appraiser’s market rent to the actual lease and use the lower figure. That is the opposite of what many owners expect. If your tenant pays above market, the market number caps you. If your tenant pays below market, the lease caps you.
Two things follow from that.
First, the money in your bank account is not the coverage figure. The lender wants an eligible lease and an appraisal-supported rent. Lease documentation matters, especially if tenants pay month to month. Lendmire’s piece How to Document Month-to-Month Rent on Your First Rental Cash-Out Refinance covers what that proof looks like.
Second, a vacant casita is not worthless to the file. The appraiser’s market rent can still support it when the unit is legal and rentable. How a given lender treats a vacant unit varies, so ask before you assume.
Form 1007 documents monthly rent. McKissock’s discussion of Form 1007 and short-term rentals notes that the lender, not the appraiser, decides how to treat the income. That is why the same appraisal can produce different rent used for lender review at different lenders.
A Worked Example With and Without the Casita
Run the numbers on a rental house with a detached casita. The ratios below are modeled assumptions for illustration, not market data.
| Scenario | Rent counted | Coverage read |
|---|---|---|
| Casita excluded | Main house only | About 0.95x |
| Casita included (legal unit) | Main house plus casita | About 1.14x |
Assume the casita’s rent used for program review equals roughly a fifth of the main house’s rent. Coverage moves from 0.95x to about 1.14x (0.95 times 1.2). The monthly obligation does not change, because the loan is the same.
Here is what that means. Many select programs start at 1.00 coverage, and stronger ratios tend to open better pricing and leverage. At 0.95x, the main-house-only file sits below that line. Coverage below 1.00 is available through select lenders in the network, with leverage and terms adjusted. At 1.14x, the file clears the 1.00 floor on its own.
Now add the value effect. If the casita may support a higher appraised value, the 75% LTV ceiling applies to a bigger number. More room under the cap does not guarantee more cash. Reserves, credit tier, and the final coverage ratio still decide what the lender will do. These specifics are subject to lender guidelines and a full review of property, leverage, and credit.
One more point of honesty. Clearing 1.00 is not positive cash flow. DSCR compares rent to PITIA only. Repairs, vacancy, management, utilities, and capital expenses sit outside the calculation. A file can clear coverage and still be thin after real operating costs.
Decision Table: Four Common Casita Situations
| Situation | How it is classified | What to verify |
|---|---|---|
| Rental house, legal casita, same parcel | One unit plus legal ADU, or 2-4 units | Permits, rent schedule form, leases |
| Rental house, unpermitted casita | Main house only | Whether legalizing is feasible |
| You live in the main house | Owner-occupied, not DSCR territory | Occupancy before anything else |
| Casita used as a short-term rental | Depends on lender and local rules | Hosting history, rent schedule treatment |
DSCR loans are designed for non-owner-occupied investment properties. Because they are business-purpose investor loans, they are reviewed differently from a standard owner-occupied mortgage. If you live in the main house and rent the casita, you are on a different path, and a pure DSCR cash-out is generally not it.
The Owner-Occupied Contrast
Owner-occupant loans do have ADU income rules. HUD’s FHA guidance in Mortgagee Letter 2023-17 allows ADU rental income for certain one-unit properties and requires that the unit be legally rentable. Those rules cover principal residences. They do not govern a DSCR refinance of an investment property, and nothing in them sets a DSCR floor or LTV for your file. Terms depend on the lender’s guidelines, the property type, the leverage, and a full review of the credit profile.
The takeaway is narrow. Even where agency-style programs accept casita income, the legality test comes first. Investor programs in the wholesale network apply the same instinct with their own guidelines.
What About Short-Term Rental Use?
If you rent the casita nightly, the file changes. Short-term rental collateral follows its own parameters. Cash-out on short-term-rental collateral tops out at 70% LTV, while cash-out on a standard long-term rental tops out at 75%. Expect a 640+ credit score and about 12 months of hosting history, with a 1.00 coverage floor on refinances. The exact numbers vary by lender and program and follow a full review of property, leverage, and credit.
Form 1007 documents monthly rent, not nightly rent, so the lender decides how to treat short-term income. 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. Some areas restrict ADUs from short-term use altogether.
What Else Has to Be True for the Cash-Out?
A casita does not override the basics. Here is where most files in the network land, subject to lender guidelines:
- Seasoning: about 6 months of ownership, measured from title recording.
- Credit: a 620 floor exists in parts of the network. Most programs want around 660, and 700+ unlocks the strongest leverage tiers.
- Reserves: commonly around 6 months of PITIA, stepping up to about 9 months on loans above $1,500,000. They vary by lender, leverage, loan size, and transaction type.
- Loan size: up to $3,000,000 on standard programs, with smaller balances routing through select lenders.
- Property type: manufactured homes, log homes, and barndominiums are not offered. If your casita is one of those, it will not work in these programs.
More equity never erases credit floors or reserve rules. The strongest files clear both tests: enough equity and enough rental coverage. For the broader picture, Lendmire’s complete DSCR loans guide walks through how programs fit together. If your rent is the main story, Lendmire’s piece Can a Retired Landlord Get a Rental Cash-Out Refinance on Rent Alone? covers that angle.
Across the wholesale network, the pattern on casita files is consistent. The deals that go smoothly settle legal status before the appraisal is ordered. The deals that stall find out mid-file that the casita was never permitted as a dwelling, and the appraisal fee is already spent.
Pitfalls Before You Order the Appraisal
Check these first. Each one can change which loan you are applying for.
| Check | If it fails |
|---|---|
| Casita permitted as a dwelling | Plan on main-house-only numbers |
| Same parcel as the main house | Different analysis, ask the lender |
| Lease in place with rent receipts | Market rent may be the only support |
| Main house is a rental, not your residence | DSCR is likely the wrong product |
| Insurance reflects the rental use | Fix the policy before the deal works |
On that last row: when a casita becomes a rental, the insurance status usually changes, and lenders review the policy. Get the coverage right before the file goes in, not during underwriting.
A final caution on expectations. A higher rent does not automatically raise value. For a house with a casita, value usually follows sales comparisons, not what the tenant pays. Do not raise the lease just before an appraisal and expect the opinion of value to move with it.
Key Terms Defined
Casita: a small detached structure, or a separate living area, on the same lot as a main house, often with its own entrance.
ADU (accessory dwelling unit): an independent living space with sleeping, cooking, and bathroom facilities on the same parcel as the main home.
Market rent: what the appraiser estimates the unit would rent for, as opposed to what your tenant actually pays.
Seasoning: the waiting period a lender wants after you buy a property before it will allow a cash-out refinance.
PITIA: principal, interest, taxes, insurance, and any HOA dues, the full monthly obligation that DSCR compares rent against.
Form 1007 / Form 1025: appraisal exhibits that report estimated rent; Form 1007 covers single-family properties, and Form 1025 reports rent per unit for 2-4 unit properties.
Frequently Asked Questions
Will my casita’s rent count if I have not pulled a permit?
Usually not. An unpermitted structure is likely to be flagged and left out of both appraised value and rent used for eligibility review. Most owners in that spot refinance on the main house alone, or legalize the unit first and then apply.
Does a casita raise the amount I can pull out, or does it only help coverage?
It can do either, and sometimes both. A legal casita may support a higher appraised value, depending on comps and underwriter review, which raises the loan ceiling. Its rent can also lift coverage. If it is excluded from the appraisal, it does neither.
Which rent does the lender use, the lease or the appraisal?
Most programs use the lower of the lease or the appraiser’s market rent. A lease well above market gets capped at market. A lease below market caps you at the lease.
Can I live in the main house and rent the casita?
That is an owner-occupied situation, not an investment property. DSCR loans are designed for non-owner-occupied properties, so a pure DSCR cash-out generally is not the right fit. Settle occupancy before you shop for a loan.
If coverage clears 1.00, is the property cash-flow positive?
Not necessarily. DSCR compares rent to PITIA only. Repairs, vacancy, management, utilities, and capital expenses sit outside the calculation, so run those separately. Tax treatment varies; consult a qualified professional.
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 broker, Lendmire arranges financing through select lenders in its wholesale network across 41 markets, including Washington, D.C. Programs are subject to lender guidelines and this is not a commitment to lend.
For how equity extraction works on an investment property, see Lendmire’s guide to cash-out refinance on an investment property.
About Lendmire
As a non-QM mortgage broker (NMLS# 2371349), Lendmire facilitates DSCR investor loans across 41 markets, including Washington, D.C. DSCR eligibility is generally reviewed around property-level rental income instead of personal income documentation, subject to lender guidelines, serving LLC-structured portfolios and self-employed borrowers who don’t fit conventional boxes. A two-time Scotsman Guide Top Mortgage Workplace (2025, 2026).
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References
1. Fannie Mae ADU income scenarios
2. McKissock: the income approach to appraisal
3. McKissock: Form 1007 and short-term rental appraisals
4. HUD Mortgagee Letter 2023-17
This article is part of Lendmire’s investment property cash-out refinance program — full qualification details, guidelines, and scenarios live on the program page.
Related reading: How to Decide to Sell or Refinance a Home You Use and Rent on Airbnb · How Much a DSCR Refinance Releases on a Part-Year Short-Term Rental · How to Decide Between a Cash-Out Refinance and Selling a Rental
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
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Compliance and disclosures. Lendmire (NMLS# 2371349) is a licensed mortgage broker and is not a direct lender, depository institution, financial advisor, or tax professional. Content in this article is general market analysis and educational information — not financial, legal, or tax advice for any specific situation. Lendmire does not guarantee loan approval; every transaction is subject to underwriting by the funding lender. Mortgage pricing and loan program guidelines are subject to change at any time without notice and vary by borrower characteristics, property type, and state regulations. Lendmire complies with Equal Housing Opportunity. Licensure verification: NMLS Consumer Access.