The Quick Read: Usually between $50,000 and $500,000, and the ADU does not raise the leverage ceiling. A legal, leased ADU can lift the rent and the appraised value that feed the formula, but the program’s percentage caps and dollar limits set the maximum line. The line is the smallest of three limits: equity room, the dollar cap, and the credit tier. Only a rental with no mortgage can reach the top of the range, subject to underwriting.
- Second lien behind a mortgage you keep: up to 70% CLTV at a 720 score or better, lines to $500,000.
- First lien on a rental with no mortgage: up to 75% LTV at 740 or better, 70% LTV at 700 to 739, lines to $500,000.
- First-lien lines above $500,000 and up to $1,000,000: 65% LTV at 720 or better.
- Rent must cover a stress payment on the entire line at 1.10x or better.
- The ADU’s rent counts only when the unit is legal and the income is documented. Final terms depend on lender guidelines, property type, leverage, and the borrower’s complete credit picture.
All figures are ceilings through select programs, subject to lender guidelines and underwriting. They are not offers.
What Is a DSCR HELOC on a Rental?
A DSCR HELOC is a revolving line of credit secured by a non-owner-occupied rental. It is written as a standalone second lien behind the first mortgage you keep, or as a standalone first lien on a rental with no mortgage. It qualifies primarily on property-level rental income covering the payment, subject to lender guidelines. No traditional personal-income documentation, W-2s, pay stubs or personal debt-to-income calculation are involved.
The rental can sit in an LLC, subject to program terms. The members sign as guarantors. A title holder who is not a borrower signs a non-borrowing owner acknowledgment and the security instrument.
The line has a 5-year interest-only draw period on the drawn balance, then a 25-year repayment period, with a 30-year maturity. The rate is variable. At least 80% of the line is drawn at closing, and the closing draw is never less than $50,000. Later draws are at least $5,000 each.
This product is not offered on an owner-occupied home or a second home. It is also not the same as the investment-property HELOC that is qualified on personal income. That is a different product with different rules, and ADU rent does not drive qualification on it. Lendmire’s piece on borrowing against an investment property HELOC to build an ADU covers that personal-income path.
How Is the Maximum Line Calculated?
The maximum line is the appraised value times the applicable ceiling, minus every existing lien, then capped by the dollar limit and the credit tier. The smallest of those three numbers wins.
On a second lien, the combined loan-to-value counts the first mortgage balance plus the full new line, divided by value. Say a rental is worth $400,000 and the first mortgage equals 40% of value. At a 70% CLTV ceiling, the second lien has room for up to 30% of value. That is the equity room. The dollar cap and credit tier then confirm or shrink it.
Here is how the tiers sit side by side.
| Position | Score | Ceiling | Line range |
|---|---|---|---|
| Second lien | 720+ | 70% CLTV | $50,000 to $500,000 |
| First lien | 740+ | 75% LTV | Up to $500,000 |
| First lien | 700 to 739 | 70% LTV | Up to $500,000 |
| First lien | 720+ | 65% LTV | Above $500,000 to $1,000,000 |
The credit floor depends on the lien position: 720 on a second lien and 700 on a first lien. A first lien exists only on a rental with no mortgage, so a borrower who keeps a first mortgage can take only a second lien, and that route starts at 720. The 65% tier for lines above $500,000 asks for 720 or better, which sits inside the first-lien floor of 700.
The $1,000,000 ceiling is first-lien only, and a mortgaged rental stops at $500,000. A declining-market flag lowers the ceiling by 5 points. The minimum line of $50,000 also means a rental with little equity may not fit.
Does the ADU Raise the Amount?
No. The ADU feeds two inputs and leaves the percentages alone.
First, the appraisal. A legal, permitted ADU may support a higher appraised value, depending on comps and underwriter review. A higher value gives more equity room under the same ceiling.
Second, the rent. A leased ADU adds to gross rent, which lifts the coverage ratio. Picture a main house that covers around 1.05x on its own. Add a permitted, leased ADU and the combined property could reach roughly 1.25x. That is an illustration, not a promise. It matters because the program tests rent against a stress payment on the whole line.
Rent is the lesser of the appraisal’s market rent and the lease, unless three months of receipts support a lease above market. A lease in place is required. A two-to-four-unit property may have at most one vacant unit.
So the ADU helps in two spots: it may add equity room, and it helps the 1.10x coverage test. It never moves a 70% ceiling to 75%.
When Does Equity Bind, and When Does Rent Bind?
Two limits compete on every file. Equity room says how much the ceiling allows. Rent coverage says how much line the rent can carry.
The coverage test uses a fully amortizing payment on the entire credit limit at a stress rate, which is the start rate plus 2 percentage points. Taxes and insurance are not part of that qualifying payment. The test runs on the full line, not on the drawn amount. A borrower who plans to draw only the minimum still gets tested on the whole limit.
Whether the first-mortgage payment joins the qualifying payment on a second lien is not published. Confirm on the file how the lender treats it. The lender’s own coverage calculation governs.
Run three cases on one modeled property, with all inputs as assumptions:
| Case | Value effect | Rent effect | Likely binding limit |
|---|---|---|---|
| No ADU | Base value | Base rent | Often equity |
| Permitted, leased ADU | May lift value | Adds rent | Equity or the dollar cap |
| Unpermitted ADU | Typically excluded | Typically excluded | Same as no ADU |
On a thin-coverage main house, the ADU’s rent can be what clears 1.10x. On a high-rent property with a large first mortgage, equity is usually the wall, and ADU rent changes little.
What Happens With an Unpermitted or Short-Term ADU?
An unpermitted ADU should be treated as outside the file. Lenders follow the appraiser’s determination of what is a legal unit. If the unit is flagged, expect it to be left out of both the value and the rent. Plan the line on the main house alone, and treat any ADU credit as a surprise upside, not a base case.
Short-term rental use is a separate question. Confirm on the file how the lender treats a short-term ADU before relying on that 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.
Unit count is another judgment call. An ADU may be classed as a one-unit property with an ADU or as a two-unit property, depending on how the appraiser and lender classify it. That choice affects the appraisal form. Fannie Mae’s appraisal forms table lists Form 1004 for one-unit properties, including those with an accessory dwelling unit, and Form 1025 for two-to-four-unit properties. It also names Form 1007 as the single-family rent schedule. That is a form-name contrast only. It is not a DSCR rule.
How Does the Appraisal Handle an ADU?
The valuation path depends on the line size. Lines to $400,000 use an automated valuation with a confidence score of 85 or better plus a property inspection report, or a full interior appraisal. Lines above $400,000 take a full interior appraisal on Form 1004, 1073 or 1025. Appraisal waivers are not accepted.
The rent schedule is where the ADU gets documented. Fannie Mae’s ADU income job aid shows an appraiser using Form 1007 for the accessory unit with an explanation that the rent is for the ADU. It also shows that when ADU rental comps are scarce, the appraiser may use adjusted non-ADU rentals. A thin rent schedule can therefore pull the rent used for lender review down.
Title follows the lien. A full title policy applies on a first lien and on second liens above $400,000. Smaller second liens use an owner-and-encumbrance report. Hazard insurance covers both liens, with flood coverage where required.
If the value comes in light, an appraisal reconsideration request with recent in-neighborhood sales and a clear description of the ADU is a routine step. Bring the permit, the lease and the ADU’s square footage so the appraiser has what is needed.
Can the Line Fund the ADU Build?
This page covers a rental that already has an ADU. The line is a standalone lien on an existing rental, with at least 6 months of seasoning, so it is not a construction loan. An ADU still under construction has no lease and may have no legal status yet, which leaves it out of rent and value.
For the build-to-borrow question, see Lendmire’s article How Much Can You Borrow on an Investment Property HELOC to Build an ADU?. Once an ADU is permitted and leased, this product becomes the better fit for tapping the equity it helped create.
Eligibility Gates That Come Before the Math
Several gates apply before any sizing starts.
- Occupancy. Non-owner-occupied one-to-four-unit rentals only. An owner living in the main house cannot use this product. The alternatives are a primary-residence HELOC or a personal-income product, which are different programs.
- Seasoning. A rental bought or refinanced inside the last 6 months is not eligible (that clock runs from the last note date to the new note date), and the owner must have held title for 6 months (settlement date to note date).
- Credit. 720 minimum on a second lien, 700 on a first lien. No 30-day mortgage late in the last 12 months. 48 months since a bankruptcy, foreclosure, short sale or deed-in-lieu.
- Exposure. At most 5 loans or $2,500,000 per borrower with the program. Count each line against it when scaling.
- Borrowers. U.S. citizens, permanent residents, and non-permanent residents with a Social Security number. Foreign nationals and ITIN borrowers are not eligible.
- Property. Rural-designated property, condotels, row homes, leaseholds, land trusts and mixed-use are outside the program. A property listed for sale in the prior 2 months is out, as is one with a solar lien.
- Reserves. None required, and no cash to close on the line itself.
- Footprint. The program is offered in 15 of Lendmire’s 16 licensed states, every licensed state except Tennessee.
LLC title deserves its own check. The DSCR HELOC allows vesting in the owner’s LLC, subject to program terms. That is not true of every HELOC product, so keep the two product types separate.
Which Product Fits an ADU Owner?
The right product depends on how much you need and what you are willing to give up.
| Factor | DSCR HELOC | DSCR cash-out refinance | Personal-income HELOC |
|---|---|---|---|
| Reviewed on | Rental income | Rental income | Borrower income and debt |
| First mortgage | Stays in place | Replaced | Stays in place |
| Rent test | 1.10x on full line | Varies by program | Not rent-tested |
| ADU rent drives it | Yes, if legal | Yes, if legal | No |
A DSCR HELOC keeps a low first mortgage intact. The cost is a lower ceiling and a 720 score requirement on a second lien. A DSCR cash-out refinance on a standard rental is generally written at up to 75% LTV, which can leave more room when equity is large. It replaces the first mortgage, though, so weigh what you give up. Lendmire’s DSCR cash-out refinance guide is the next stop if the HELOC runs short.
On broader market context, NerdWallet’s explainer on investment-property HELOCs says the lender pool is smaller and requirements are stricter than on a primary home, and that more than one appraisal may be required. It sets a baseline of at least 20% equity. That is a market-wide floor, not this program’s number. On this program, the 70% CLTV ceiling on a second lien means roughly 30% of value must remain unencumbered after the new line.
For the full picture of how these loans work, see the complete DSCR loans guide.
Key Terms Defined
DSCR: Debt service coverage ratio, meaning gross monthly rent divided by the qualifying payment.
CLTV: Combined loan-to-value, meaning the first mortgage plus the new line, divided by value.
ADU: An accessory dwelling unit, a separate living space on the same lot as the main house.
Stress payment: A fully amortizing payment on the entire credit limit at a higher test rate, used only to qualify.
Draw period: The 5 years when you can draw on the line and pay interest only on the balance drawn.
What Lenders Will Ask For
A clean ADU file has fewer preventable gaps. Gather these before the file goes in:
- The signed lease for the main house and for the ADU
- The ADU permit and certificate of occupancy, or the local equivalent
- Three months of rent receipts if a lease sits above market rent
- Entity documents if the rental sits in an LLC
- The current first-mortgage statement on a second lien
- Hazard insurance, plus flood coverage where required
- A clear description of the ADU’s size, entrance and utilities for the appraiser
The common failure points are an unpermitted unit, a lease that does not match the rent schedule, and an LLC whose members have not signed as guarantors. Each is fixable before submission, not after.
Frequently Asked Questions
Does ADU rent count toward the coverage test?
Yes, when the unit is legal and the income is documented. A permit and a signed lease are the core evidence. Rent from an unpermitted unit is typically left out, subject to lender guidelines.
Can I reach $1,000,000 on a rental with an ADU?
Only on a first lien with no mortgage on the property, and only at 65% LTV with a 720 score or better. A mortgaged rental is limited to a second lien, which stops at $500,000 and 70% CLTV. Underwriting, valuation and title can reduce the line further. These specifics are subject to lender guidelines and a full review of property, leverage, and credit.
How long must I own the rental before applying?
Two six-month clocks apply: the line is not available on a rental bought or refinanced in the last 6 months (last note date to new note date), and title must have been held for 6 months (settlement date to note date). A recent purchase or refinance fails the first clock regardless of how long the ADU has been leased.
Does my personal income matter?
No traditional personal-income documentation, W-2s or personal income calculation are used. The line qualifies primarily on property-level rental income covering the stress payment, subject to lender guidelines. Credit score and mortgage history are still reviewed, and the valuation and lease are documented.
What if the line comes in too small?
A DSCR cash-out refinance on a standard rental is the usual alternative, since it replaces the first mortgage and can reach a higher ceiling. A smaller line also can mean low equity, where the $50,000 minimum is the obstacle. Compare the options against the property, rent, equity, credit and goals.
If you are considering a home equity line on a rental property and want to see how the numbers work, Lendmire can help you compare DSCR HELOC options based on the property, the rent, the equity available, credit profile, combined leverage, and your goals.
About Lendmire
Lendmire (NMLS# 2371349) is a mortgage brokerage serving landlords and real estate investors in 16 licensed states. DSCR home equity lines of credit on non-owner-occupied one-to-four-unit rentals are arranged through wholesale lending channels in 15 of those states (every licensed state except Tennessee); Lendmire brokers the line and the lender underwrites each application on the property’s rent, credit and leverage. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.
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Informational only. Not a Loan Estimate, approval, or commitment to lend. Program availability and eligibility are subject to lender guidelines, credit approval, property review, and underwriting.
References
1. Fannie Mae’s appraisal forms table
2. Fannie Mae, ADU Income Job Aid
3. NerdWallet’s explainer on investment-property HELOCs
This article is part of Lendmire’s DSCR HELOC program — full qualification details, guidelines, and scenarios live on the program page.
Related reading: Top DSCR HELOC Providers for Investment Property Owners With Built-Up Equity · Best DSCR HELOC Program on an Airbnb Investment Property · Top DSCR HELOC Providers to Fund a Rental Property Remodel
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
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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.