Using a HELOC for a Down Payment: Qualification, Risks, and Taxes

Using a HELOC for a down payment on another property is allowed under Fannie Mae, FHA, and (by lender discretion) VA rules, provided the line is secured by an asset you own and the payment is counted against you when the new mortgage is underwritten. It works, but it’s a two-hurdle transaction: you have to qualify for the HELOC, then qualify for the new mortgage while carrying it. The interest is usually not deductible in this scenario, and the line itself carries risks that don’t exist with cash.

What Each Loan Program Allows

Fannie Mae classifies a HELOC on your existing home as “borrowed funds secured by an asset” and accepts it as a source for down payment, closing costs, and reserves. The reasoning is that you already own the equity, so you’re converting your own wealth into cash rather than adding purely unsecured debt.¹

FHA takes a similar position through its collateralized-loan rule: a loan from an independent third party secured by an asset you own is acceptable, so a HELOC works as long as the HELOC lender isn’t the seller, the real estate agent, or the lender writing the new FHA mortgage. Unsecured borrowing, such as credit card cash advances or signature loans, is explicitly prohibited as a down payment source.²

FHA layers on extra conditions. The secondary financing payment has to be included in your qualifying ratios, the combined loan-to-value of the FHA mortgage plus the secondary financing can’t exceed FHA’s standard LTV limits, and the second lien can’t have a balloon payment within ten years.²

VA loans generally don’t require a down payment at all, which makes this strategy largely irrelevant for VA borrowers. The VA’s buyer’s guide doesn’t specifically address HELOCs, so if you did want to put money down voluntarily, the rules would come from the individual lender’s overlays.

How the HELOC Payment Affects Your New Mortgage Qualification

This is where the strategy most often falls apart. The new mortgage lender must count the HELOC’s monthly payment as recurring debt when calculating your debt-to-income ratio. If your HELOC doesn’t require monthly payments during the draw period, or if you’re on an interest-only plan, the lender still has to calculate an equivalent payment and include it. A promotional introductory rate doesn’t help either: the underwriter must use the fully indexed rate to compute what the payment would be.¹

Fannie Mae’s automated underwriting caps total DTI at 50%. Manually underwritten conventional loans face a stricter 36% ceiling, which can stretch to 45% when compensating factors such as a high credit score and significant reserves are present.³

Consider what that looks like in practice. Take a borrower earning $8,000 a month with $1,200 in existing monthly debt payments. A $300 interest-only HELOC payment plus a $2,100 projected new mortgage payment brings total obligations to $3,600, or 45% DTI. Under automated underwriting there is almost no cushion left, and under manual underwriting the file wouldn’t qualify without strong compensating factors. The practical result is that a HELOC-funded down payment shrinks how much house the new mortgage will approve.

One more mechanical point: if you’re also using the same financial asset to demonstrate cash reserves, the lender subtracts the borrowed amount plus fees. You can’t count the same equity twice.¹

Documentation the New Lender Will Require

Fannie Mae requires three items: the terms of the HELOC, evidence that the HELOC lender is not a party to the home sale, and proof that the funds have actually been transferred to you. An approved credit line isn’t enough. The money has to have moved.¹

Mortgage lenders also review at least 60 days of bank statements, and any large deposit during that window needs a paper trail. A HELOC draw that lands in your checking account will trigger sourcing questions, and the correct response is full disclosure: the signed HELOC agreement, the draw statement showing the transfer, and confirmation that the HELOC lender has no connection to the property sale. Drawing early to let the funds “season” past 60 days is a maneuver underwriters are trained to catch, and an unexplained large deposit followed by a mortgage application draws more scrutiny than a well-documented HELOC draw.

Qualifying for the HELOC in the First Place

You need enough equity in your current home to borrow against. Most traditional banks cap the combined loan-to-value at 80%, meaning your existing mortgage balance plus the HELOC limit can’t exceed 80% of the appraised value. Some credit unions and online lenders push the CLTV to 90% or 95%, but those products carry higher rates and stricter credit requirements.

Applying involves a full financial review: income verification through pay stubs and tax transcripts, a new appraisal of your current home to establish current value, and a credit pull. Once you’re approved, the draw period begins (typically ten years), and you can access funds as needed and generally pay interest only on what you’ve drawn.

Timing matters. HELOC funding isn’t instant, and any delay between draw request and disbursement can jeopardize a purchase contract. Draw the full down payment amount and get it documented well before closing rather than cutting it close.

Risks That Follow You After Closing

The Line Can Be Frozen or Reduced

Federal regulation lets a HELOC lender freeze or cut your credit line in three situations: when the value of your home drops significantly below the original appraised value, when the lender reasonably believes you can’t meet your repayment obligations due to a material change in finances, or when you default on a material term of the agreement.⁴

“Significant decline” is defined as a drop that erases 50% or more of the initial equity cushion between your credit limit and the appraised value. If your home was appraised at $400,000 with a $300,000 mortgage and a $60,000 HELOC limit, the cushion above the HELOC is $40,000. A $20,000 decline in value cuts that in half and can trigger a freeze. The risk matters most when you plan to draw the HELOC later: if the market turns between opening the line and needing the money, the funds may not be there when your closing date arrives.⁴

Variable Rates and the Lifetime Cap

Almost all HELOCs carry variable interest rates. Federal law requires each agreement to disclose a lifetime maximum rate, but doesn’t set that ceiling; lenders choose it.⁴

A common structure sets the cap five percentage points above your starting rate. Open at 8.5%, and your rate could reach 13.5%. On a $60,000 balance, that’s the difference between $425 and $675 in monthly interest alone. When the HELOC sits alongside a new mortgage you already stretched to qualify for, a rate climb hits twice. Before drawing, check the lifetime cap in your agreement and calculate the worst-case payment. If you can’t absorb it alongside the new mortgage, the plan is too fragile.

The Payment Jump When the Draw Period Ends

Most HELOCs run a ten-year draw period, then convert to a repayment phase of 10 to 20 years where you pay principal and interest on a standard amortization schedule. The payment change can be steep. A $50,000 balance at 9% costs about $375 a month in interest-only mode; the same balance amortized over 20 years runs roughly $450. At 11%, the repayment-phase payment is about $516. Borrowers who never planned for the transition are the ones who get hurt.

Tax Treatment Changed Permanently in 2025

The One Big Beautiful Bill Act made the Tax Cuts and Jobs Act’s mortgage interest provisions permanent in 2025. Interest on a HELOC is deductible only if the borrowed funds are used to buy, build, or substantially improve the home that secures the loan. HELOC funds drawn from your primary residence and used as a down payment on a different property do not qualify.⁵

The $750,000 acquisition-debt cap across your primary residence and one second home still applies, and it covers both first mortgages and any HELOC used to improve the securing property.⁶

The exception worth knowing about: if the HELOC proceeds buy a rental property, IRS interest tracing rules let you categorize the interest based on how the money was actually used. Interest allocable to producing rental income goes on Schedule E and offsets rental income; interest allocable to other investment property goes on Schedule A as investment interest, deductible only up to net investment income for the year. If you split a HELOC between a renovation and a down payment on another property, you have to track each dollar and allocate the interest yourself. The 1098 from your HELOC lender reports total interest paid, not how it’s classified.⁶⁷

When This Strategy Fits

The approach works best in a narrow set of conditions: substantial equity in the current home, strong income relative to total debt, and a clear repayment plan for the HELOC within a few years. Real estate investors buying rentals often use it because rental income helps service the HELOC and the interest may be deductible as a business expense through the tracing rules.

It falls apart when the borrower is stretching to qualify. If adding the HELOC payment pushes your DTI toward the lender’s ceiling, you’ve built a structure with no room for a job loss, a rate increase, or a credit-line freeze, any one of which can cascade into problems on both properties. In that position, saving a cash down payment is usually cheaper than carrying two leveraged properties on razor-thin margins, even if it takes longer.

1
Fannie Mae. Borrowed Funds Secured by an Asset
2
U.S. Department of Housing and Urban Development. FHA Single Family Housing Policy Handbook 4000.1
3
Fannie Mae. Debt-to-Income Ratios
4
Consumer Financial Protection Bureau. 12 CFR 1026.40 – Requirements for Home Equity Plans
5
Internal Revenue Service. Real Estate Taxes, Mortgage Interest, Points, Other Property Expenses
6
Internal Revenue Service. Publication 936 (2025), Home Mortgage Interest Deduction
7
Internal Revenue Service. Other Deduction Questions