HELOC Requirements When You Rent Out a Basement or ADU at Home

The Quick Read: Renting a basement or ADU does not automatically disqualify a home from a HELOC, but three things decide the outcome: whether you still live in the property, whether the rented unit is legal and permitted, and whether the line’s own terms allow tenants, all of which a lender reviews alongside credit, debt-to-income, and combined leverage.

• If you live in the main house and rent the basement or ADU, the file usually stays a primary residence. On a primary residence, the network ceiling reaches 90% CLTV only at a 720-or-better credit profile and only on lines up to $500,000.
• If you move out and rent the whole property, it becomes an investment property. On an investment property, the ceiling is 70% CLTV, with a 700 minimum credit score and a $500,000 maximum line.
• A HELOC qualifies the borrower on credit and debt-to-income, not on the rent. Rent is supporting evidence at most.
• An unpermitted unit or an LLC on title can stop the file. A DSCR cash-out refinance is the usual path once the unit is legal, leased, and held as a rental.

All figures are typical network guidelines and are subject to lender guidelines and full file review. This is not a commitment to lend.

How Underwriting Treats a Home With a Rented Unit

The questions below tend to run in a set order. The first answers set the product, and the later ones set the size of the line. Lendmire brokers HELOCs through select wholesale partners, so the steps below reflect how those programs read a home with a tenant in it.

1. Classify the property. The lender decides whether the home is a single-family residence with a rented unit or a 2-4 unit property. The 2-4 unit class is eligible on the 5-year draw structure, with a 640 minimum credit score.

2. Classify occupancy. You live in the main house and rent the basement or ADU, and the file is typically still a primary residence. You move out and rent everything, and it becomes an investment property with a lower ceiling and a higher credit floor.

3. Check title. Title must sit with the individual borrower or a revocable living trust. LLCs, corporations, partnerships, and irrevocable, blind, or land trusts cannot hold title on these lines.

4. Confirm the unit is legal. A basement or garage unit that was never permitted can be excluded from value and from any rental income the lender looks at.

5. Size the line from equity. The lender takes value times the CLTV cap and subtracts existing liens. The cap depends on occupancy and credit tier, and it shrinks as the credit score falls.

6. Qualify the borrower. Debt-to-income tops out at 50%, and it is 45% for credit profiles from 600 to 679. The lender reviews your file on the interest-only payment calculated on the maximum draw, not on what you plan to borrow.

7. Value the home. Lines at or below $500,000 ordinarily use an automated valuation. A full appraisal is required on every line above $500,000, and a borrower may request one in any case.

Occupancy Sets the Ceiling

The same house gets different limits depending on who sleeps in it. The table maps the common situations to the usual treatment. Each row is subject to lender guidelines.

Here are the network figures behind those rows. On a primary residence, lines run $25,000 to $750,000. A 720+ profile reaches 90% CLTV up to $500,000 and 75% CLTV up to $750,000. At 700+, the ceiling is 85% CLTV up to $500,000. Credit tiers step down from there, and a 620 profile reaches 70% CLTV up to $400,000. On an investment property, a 700-or-better profile reaches 70% CLTV up to $500,000, and nothing sits above that.

A line above $500,000 is primary-residence only. It requires a 700 credit profile or better (720 on the 5-year draw structure), caps at 75% CLTV, and needs a full appraisal.

Two draw structures exist on primary residences. One runs a 3-year interest-only draw into a 17-year repayment. The other runs a 5-year draw into a 25-year repayment. Investment lines use only the 5-year draw and 25-year repayment structure. At least 75% of the line is drawn at closing on either one.

The program is limited to Lendmire’s 16 full-service states, which is narrower than the 41-market DSCR footprint.

Key Terms Defined

HELOC: A revolving line of credit secured by the home, with a draw period followed by a repayment period.

ADU: An accessory dwelling unit, meaning a separate living space on the property with its own entrance, kitchen, and bathroom.

CLTV: Combined loan-to-value, which adds every lien on the property and divides by the home’s value.

Owner-occupied: A property the borrower lives in as a primary residence.

Non-owner-occupied: A property the borrower rents out or holds as an investment instead of living in it.

DSCR: Debt service coverage ratio, which divides a property’s monthly rent by its full monthly housing obligation (principal, interest, taxes, insurance, and any HOA dues).

Documents the File Needs

Clean paper keeps the review short on questions. Plan for these:

• An application that states occupancy accurately and discloses the rental.
• The lease, plus proof that rent is actually received, if any rent is part of the file.
• Proof the unit is legal, such as a permit record or certificate of occupancy.
• A valuation, which is automated for most lines at or below $500,000 and a full appraisal above that.
• A title and vesting check showing the individual borrower or a revocable trust.
• A credit report no more than 90 days old at closing, with no rescores.
• A list of your other financed properties, because a borrower is limited to three lines and a borrower with more than 15 financed properties is not eligible.

Occupancy is the item with the most downside. A Philadelphia Fed working paper finds that occupancy misrepresentation persists and tracks with elevated default risk. HELN News reports that open-end junior liens are generally not available on investment properties, which is the pressure that pushes some borrowers toward a false owner-occupancy claim. State the real occupancy. Pick the product that fits it.

Where the General Rule Breaks

The occupancy rule is simple. The edge cases are where files stall.

The line’s contract may prohibit renting. The CFPB’s HELOC booklet warns that renting the home to other people may be prohibited under the line of credit. Read the agreement before you list the unit. An owner-occupied line later used as a tenant-occupied rental can breach its terms.

The same booklet says the line can shrink. A lender can reduce or freeze a line, for example if the home’s value falls. Do not plan a build budget around a line you have not yet drawn. The booklet also says that selling the home generally requires paying off the HELOC in full, so map how a later sale or refinance retires the line.

A basement is not always an ADU. Freddie Mac’s ADU guidance treats independence from the main dwelling as a defining feature, and a basement with unrestricted access to the main unit does not qualify. That is an agency definition. HELOC and DSCR programs set their own, but the pattern is useful: a separate entrance, kitchen, and bath make a unit easier to treat as a unit.

Unpermitted space gets excluded. A converted basement without permits can be left out of value and rent on both the HELOC and DSCR sides. Fixing the permit first is cheaper than arguing about it during property review.

Future rent earns no credit. Rent from an ADU that has not been built or leased generally does not count. The lender measures the home as it stands today, not the finished ADU. Funding the build with a line is a different question from qualifying on the rent the build might produce.

An LLC deed stops the file. A property already deeded to an LLC needs a vesting change before a HELOC, or a DSCR cash-out refinance instead, subject to program terms.

Short-term rental of the unit. Treatment depends on lender policy, and rent may count for less or not at all. 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.

The agency contrast. Agency rules, which are separate from the programs discussed here, may count some ADU rent on a primary residence. They do not govern DSCR files or the HELOC programs described here, and the network’s HELOC programs generally underwrite the borrower rather than the rent.

Moving out. Opening a line as a primary residence and then converting the house to a full rental changes the occupancy the lender priced. Disclose the plan early.

A Worked Example (Ratios and Percentages Only)

Picture a borrower who lives upstairs in a single-family home and rents a permitted basement apartment. Title is held in the borrower’s name, credit sits at 720 or better, and the line is at or below $500,000. That file reads as a primary residence. The 90% CLTV ceiling is available, but the existing first mortgage counts toward combined leverage. A lender may also want meaningful retained equity. Debt-to-income, not the basement rent, carries the approval.

Now change one fact. The borrower moves out and rents the whole house. The occupancy becomes investment property. The ceiling drops to 70% CLTV, the credit floor rises to 700, and the 5-year draw structure is the only one offered. Equity that supported the first file may not support this one.

When a DSCR Cash-Out Refinance Takes Over

A HELOC can fund the ADU build from personal income. Once the unit is permitted, finished, and leased, the property can be underwritten as a rental. A DSCR loan compares the property’s rent to its full monthly obligation. It qualifies primarily on property-level rental income covering the payment, subject to lender guidelines. Lendmire’s complete DSCR loans guide walks through the mechanics.

On a standard rental, cash-out refinances top out around 75% LTV, and about 6 months of seasoning is the common expectation. A coverage ratio of 1.00 is where many select programs start. A separate select-lender path goes below 1.00, with leverage and terms adjusted. Most programs want around 660 credit, and 700+ opens the strongest leverage tiers. Reserves vary by lender, leverage, loan size, and transaction type. They commonly run around 6 months of PITIA.

Clearing 1.00 is not the same as positive cash flow. The ratio compares rent to PITIA only. Repairs, vacancy, management, utilities, and capex sit outside it. Manufactured homes, log homes, and barndominiums are not offered on the DSCR side, and an unpermitted unit does not help the file there either.

For deeper comparisons, see Lendmire’s piece Rental HELOC Requirements When a Home Equity Investment Is Owed at Sale.

What the Decision Looks Like in Practice

Start with whether you plan to keep living there. If yes, a HELOC under the owner-occupied limits may work, provided the line’s terms allow a tenant and the unit is legal. If you plan to move out, price the investment limits now (70% CLTV, 700 credit, 5-year draw structure only) and compare them against a DSCR cash-out refinance on the finished, leased property.

Agency ADU rules have loosened in recent years, as BiggerPockets covers, but that does not change how these HELOC or DSCR programs read a file.

If you are considering a home equity line and want to see how the numbers work, Lendmire can help you compare HELOC options based on the property, the equity available, credit profile, combined leverage, and your goals. Reach the team at 828-256-2183 or request a quote through the mortgage quote page.

About Lendmire

Lendmire, NMLS# 2371349, is a mortgage brokerage that arranges home equity lines of credit through wholesale lending partners in its 16 full-service states. Lines on primary residences, second homes and investment properties are each reviewed individually by the lender under the program’s occupancy, credit and combined-loan-to-value guidelines. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.

References

1. Philadelphia Fed: Owner-Occupancy Fraud and Mortgage Performance

2. HELN News: HELOC fraud and real estate investors

3. CFPB: HELOC booklet

4. Freddie Mac: ADU FAQ

5. BiggerPockets: Agency ADU rule changes