The Quick Read: This line of credit can fund an ADU build when two tests both pass. The lender confirms your income from a year or two of documented deposits, and your home has enough current equity to support a revolving second-lien line sized to the construction budget. The income test is separate from the equity test, and a strong result on one never rescues a weak result on the other.
- Qualification runs on documented income under the applicable program, subject to lender guidelines.
- The line is sized on your home’s current value, not on what the finished ADU might be worth.
- On an investment property, the network ceiling is 70% combined loan-to-value, with a 700 minimum credit profile and a $500,000 maximum line.
- Interest starts accruing on the drawn balance while the unit produces no rent.
- A DSCR refinance after the ADU is leased is the common exit, and whether ADU rent counts depends on the program.
Key Terms Defined
Bank statement HELOC: a home equity line of credit where income is documented from bank deposits instead of tax-return income. It is still a revolving second lien.
ADU (accessory dwelling unit): a separate living space on the same lot as a main home, such as a detached cottage, garage conversion, or attached suite.
CLTV (combined loan-to-value): your first mortgage balance plus the new line, divided by the home’s value.
Draw period: the stretch when you can borrow from the line and, under these programs, pay interest only.
Repayment period: the stretch after the draw period when you pay down principal and interest until the balance is gone.
Expense factor: the share of business-account deposits an underwriter treats as business cost rather than income.
DSCR (debt service coverage ratio): monthly rent divided by the full monthly housing payment, which lenders use to qualify rental property loans.
How large a line the equity supports.
An equity line is sized by combined loan-to-value, occupancy, and credit — not by rental coverage. Switch the occupancy or the credit band and the ceiling moves with it.
Investment-property lines require a 700 minimum credit score; second-home lines start at a 640 minimum and primary-residence lines at 600, and the combined-LTV ceiling steps down as the credit band drops on primary-residence and second-home lines and holds on investment-property lines; the line cap steps down on primary-residence lines and holds at every tier on investment-property and second-home lines.
A debt-to-income ratio above 45% requires 680+ credit. Profiles under 640 are limited to single-family homes. At least 75% of the approved line is drawn at closing. Ceilings, floors, and caps update from Lendmire’s centralized guideline source.
Line estimate
Illustrative estimate only — not a quote, Loan Estimate, approval, or commitment to lend. The rate is an editable assumption; equity-line pricing is variable through both the draw and repayment periods and never converts to fixed. Occupancy and credit drive the ceiling together: an investment property tops out at 70% combined LTV (minimum credit 700, line cap $500,000); a second home tops out at 90% combined LTV (minimum credit 640, line cap $500,000), with the ceiling stepping down as the credit band drops (the cap holds at every tier); a primary residence tops out at 90% combined LTV (minimum credit 600), and its $750,000 maximum line is available only at 75% combined LTV or below with a 700-or-better credit profile (720 on the longer-runway program) and a full appraisal. Lines above $500,000 require a full appraisal. Credit, debt-to-income, property type, and full underwriting review all affect the final line.
Can You Really Fund an ADU This Way?
Yes, with conditions. The “bank statement” label only describes how income is documented. The product underneath is an ordinary HELOC: you borrow against equity in a home you already own, and the lender takes a lien behind or ahead of your existing mortgage.
That lien structure is the appeal for ADU builders. You keep your first mortgage in place, and you pay for construction out of equity you have already built. Many self-employed investors also report taxable income that sits well below their real cash flow, because business write-offs shrink the number on the return. Deposit-based documentation reads the cash flow that actually reaches the account.
The catch is that an ADU build adds two problems a normal HELOC never faces. The new unit does not exist yet, so it cannot collateralize anything. And it produces no rent during construction, so the line carries cost with no offsetting income. Everything below is built around those two facts.
How Underwriting Treats It, Step by Step
Underwriting follows six steps, and each one can stop the file.
1. Collateral and occupancy. The lien goes on the home where the ADU will be built. Whether that home is your primary residence, a second home, or an investment property sets the leverage ceiling, the minimum credit score, and the maximum line.
2. Income from deposits. The lender reviews personal or business statements, commonly twelve or twenty-four months, and averages eligible deposits into a monthly figure. Business-account deposits usually take an expense factor. Personal-account deposits generally skip it but must clearly be earned income.
3. Debt-to-income. Total monthly obligations are measured against that averaged income. The network maximum is 50%, and 45% for credit profiles from 600 to 679. A ratio above 45% requires a 680 minimum. The new line is qualified on the interest-only payment calculated on the maximum draw, so you are tested on the full line, not just what you borrow first.
4. Equity test. The lender adds your first mortgage and the new line, then divides by current value. The result must sit under the CLTV cap for your credit tier and occupancy.
5. Valuation and title. Lines at or below $500,000 ordinarily run an automated valuation with no traditional appraisal, though a higher CLTV may trigger a secondary valuation. Every line above $500,000 needs a full appraisal, and you can request one in any case. Lines above $500,000 are also primary-residence only and carry a stricter credit minimum than the general floor.
6. Closing and draws. After closing, you draw funds and pay contractors in stages, within the program’s draw rules.
Across the wholesale network Lendmire places files with, programs share this skeleton. Details such as deposit treatment and expense factors vary by lender, so the match between your file and the program matters more than any single headline number.
How Deposits Become Qualifying Income
The method is simple, and the cleanup is where files get tangled. The lender totals eligible deposits across the statement window, applies the expense factor if the account is a business account, adjusts for your ownership share, and divides by the number of months. A flat factor can understate or overstate real cash flow, and some programs accept a CPA-prepared profit-and-loss statement or expense letter in its place.
Underwriters strip out anything that is not earned revenue. This table shows how that sorting usually goes.
| Deposit type | Usual treatment | Why |
|---|---|---|
| Customer or client payments | Counts | Earned income |
| Transfers between your accounts | Removed | Not new money |
| Loan proceeds or refunds | Removed | Not earned |
| One-off large deposits | Sourced, often removed | Not repeatable |
| Business deposits | Expense factor applied | Costs come out first |
Commingled accounts are the hardest to read. If personal and business money move through the same account, the underwriter has to guess which deposits are revenue. Separating them before the statement window starts gives the cleanest picture. A borrower without a recent window of business or earned deposits has nothing to average, and this method does not fit that file.
What the Network Allows by Occupancy
Occupancy decides almost everything, so check it first. Because the title of this guide does not specify one, here are all three side by side. Every figure applies to select lenders in the wholesale network, subject to lender guidelines and full file review.
| Occupancy | Top CLTV | Minimum credit | Maximum line |
|---|---|---|---|
| Primary residence | 90% at 720+ | 600 | $500,000 at 90% CLTV; $750,000 at 75% CLTV, 700+ (720 on the longer-runway program) |
| Second home | 90% at 720+ | 640 | $500,000 |
| Investment property | 70% | 700 | $500,000 |
The 90% ceiling exists only at a 720-or-better credit profile and only on lines up to $500,000. On a primary residence, a 700 profile reaches 85% up to $500,000. A 640 profile reaches 80%. A 620 profile reaches 70% up to $400,000, and a 600 profile reaches 60% up to $400,000. A primary-residence line above $500,000 requires a stricter credit minimum, caps at 75% CLTV, and needs a full appraisal.
These tiers are network figures, and they are the ones that govern files placed through Lendmire. Figures quoted elsewhere for equity lines describe the broader market and should not be read as available here.
Other structural rules matter for ADU builders:
- The property can be a single-family home, a 2-4 unit building, a PUD, a townhome, or a condominium, including non-warrantable condos. Manufactured homes, co-ops, condotels, log homes, and commercial, mixed-use, or agricultural-zoned property are not eligible.
- Title must sit with you personally or with an inter vivos revocable living trust.
- A borrower is limited to three lines and cannot own more than 15 financed properties.
- Availability is narrower than the DSCR footprint. This line is offered only in Lendmire’s 16 full-service states: AL, CA, CO, FL, GA, IN, MI, MT, NM, NC, OH, PA, TN, TX, VA, and WA.
Sizing the Line to Your Build
Start with the equity you have today, because the lender will. Run the CLTV cap against current value and subtract your first mortgage. What remains is the most the line can be, before the maximum-line limit applies.
Picture a primary residence where the first mortgage sits at 60% of current value, and your credit profile supports an 85% cap. The new line can reach up to 25% of current value. Now take a different house, an investment property with a first mortgage at 50% of value. The 70% ceiling leaves 20% of current value. Occupancy alone, even with a lighter first mortgage, leaves noticeably less room.
Many owners expect post-build value to count. Most lenders do not size a line that way. A BiggerPockets thread on ADU build financing describes the same pattern: lenders lend against current equity through a second mortgage or HELOC, and renovation-style construction loans are the alternative for after-completion value. If the budget exceeds what current equity supports, the gap needs another source of capital, a different loan type, or a smaller build.
Add a contingency to the budget before comparing it to the line. Construction costs move, and the line cannot be enlarged after closing without a new application.
Tax treatment can depend on how the funds are used and how the property is held; borrowers should keep clear records and speak with a qualified tax professional before relying on any deduction.
Draws, Carry, and the Variable Payment
This is the part that surprises people. A HELOC is built for borrowing as you go, and the CFPB’s HELOC booklet describes it as a loan that lets you borrow, spend, and repay as you go, using your home as collateral. The same booklet warns that you could lose your home if you cannot repay on schedule.
On these programs, at least 75% of the line is drawn at closing. If your budget is smaller than the line, size the line closer to the budget. Otherwise you carry interest on money that is not yet working.
Primary residences and second homes have two draw structures: a 3-year interest-only draw followed by 17 years of full amortization, and a 5-year interest-only draw followed by 25 years. Investment lines use the 5-year draw and 25-year repayment structure only. Pricing floats through both periods and never converts to fixed.
Experian explains that a draw period typically runs five to ten years, followed by a repayment period of around twenty. It also notes that some HELOCs carry a balloon payment, with the entire balance due when the draw period ends. The programs described here fully amortize, but you should confirm the structure on any line you consider.
Two cash-flow facts follow:
- During construction, the ADU generates no rent, so you pay interest on the drawn balance out of your other income.
- When the draw period ends and amortization begins, the payment steps up. Plan for that step before you sign, not after.
Choosing the Right ADU Financing Route
A bank statement HELOC is one of several routes. The right one depends on your property, equity, income documentation, and how you intend to use the unit.
| Route | Income proof | Draw style | Best fit |
|---|---|---|---|
| Bank statement HELOC | Deposits | Revolving line | Existing first mortgage worth keeping |
| Cash-out refinance | Varies by program | Lump sum | Replacing the first mortgage |
| Construction loan | Full file review | Milestone draws | Budget above current equity |
| DSCR loan | Property rent | Lump sum | Stabilized, leased property |
DSCR usually does not work as the build loan. The test compares rent to the full payment, and an unbuilt ADU has no rent. Where the property has other units already leased, the rent of those units can carry the test, subject to program guidelines. A DSCR loan is better understood as the take-out after construction. Lendmire’s complete DSCR loans guide covers how those programs work in detail.
Where the General Rule Breaks
The steps above describe a typical file. These edge cases bend them.
The collateral is an investment property. The ceiling drops to 70% CLTV, the minimum credit profile rises to 700, and the maximum line is $500,000. One investor on BiggerPockets described being unable to find a lender for a HELOC on an investment property. That matches the narrow lane here, which is why occupancy is the first filter.
The property is titled in an LLC. LLCs, corporations, partnerships, and irrevocable, blind, or land trusts cannot hold title on this line. A property already deeded to an LLC needs a vesting change first, or a DSCR cash-out refinance instead, subject to program terms.
The build costs more than the line. Current equity sets a hard limit. When the budget exceeds it, a construction loan or a staged combination of sources may fit better.
The appraisal does not credit the cost. The exit plan often assumes you will reappraise after completion and refinance out of the line. A BiggerPockets discussion of ADU exit strategy shows the risk: when few comparable sales exist, an appraiser may credit the unit well below its construction cost, leaving value trapped. An improvement may support a higher appraised value, depending on comps and underwriter review, but never assume it will recover its cost.
A bankruptcy or foreclosure sits in the history. A bankruptcy needs 4 years of seasoning from discharge or dismissal. Foreclosure-family history splits by program: one seasons a foreclosure at 7 years and a deed-in-lieu, pre-foreclosure, or short sale at 4, while the other declines that history entirely.
The property was recently listed for sale. In several states, a property listed for sale or listed within the past 60 days is ineligible.
The ADU itself is an ineligible type. If the plan is a manufactured, log-built, or barndominium-style unit, note that those construction types are not offered on the DSCR side, and manufactured homes are not eligible collateral on the line either.
Zoning and permits sit outside the loan. The lender decides credit, and the local authority decides whether the ADU is allowed. Confirm both before you close.
The Exit: From Line to Long-Term Financing
Many investors plan to refinance after the unit is built and leased. The natural take-out is a DSCR loan on the multi-unit or ADU-bearing property.
Know what that test measures. DSCR compares rent to the full monthly housing payment: principal, interest, taxes, insurance, and any HOA dues. Clearing 1.00 is where many select programs start, and a separate select-lender path takes coverage below 1.00 with leverage and terms adjusted. Stronger coverage opens better pricing and leverage.
Clearing the ratio is not the same as positive cash flow. Repairs, vacancy, management, utilities, and capital expenses sit outside the calculation. Whether ADU rent counts toward the ratio depends on the program’s guidelines and on how the unit is documented, so confirm before you build the plan around it.
The cash-out ceiling matters on the way out as well. Cash-out refinances on standard rentals top out around 75% LTV across most of the network, with about six months of seasoning as the common expectation. Short-term rental collateral runs lower, with cash-out at 70%. Terms vary by lender guidelines, property type, leverage, credit profile, and full file review.
Is This Route Right for You?
It tends to fit when most of these are true:
- You have a clean, documentable window of earned deposits.
- You own the home in your own name or a revocable living trust.
- Your first mortgage is worth keeping, and your equity covers the budget plus contingency.
- You can carry the interest on the drawn balance until the unit rents.
- You plan a refinance exit and have tested the appraisal risk.
It tends to fit poorly when your deposits are tangled together, when title sits in an LLC, when the budget outruns current equity, or when your plan depends on post-build value to fund the build.
If you are weighing other documentation paths, Lendmire’s overview of the bank statement HELOC explains how deposit-based qualification works for self-employed borrowers.
Frequently Asked Questions
Can I use a bank statement HELOC on a rental property to build an ADU?
Sometimes. On an investment property, the network ceiling is 70% CLTV with a 700 minimum credit profile and a maximum line of $500,000. Title must be held by you or a revocable living trust, subject to lender guidelines. Many owners find the primary-residence version easier to fit.
Does the line count future ADU rent as income?
No. During construction the unit produces no rent, and the line is reviewed on your documented deposit income. After the unit is leased, whether its rent counts for a DSCR refinance depends on that program’s guidelines.
How much of the line do I have to draw at closing?
At least 75% on both wholesale programs. That means you should size the line close to the real budget rather than borrowing a large cushion you will not use.
What credit score do I need?
It depends on occupancy. Primary residences start at 600, second homes at 640, and investment properties at 700. The 90% CLTV tier requires 720 or better, and most borrowers sit in a middle tier with a lower ceiling.
What happens when the draw period ends?
Payments move from interest only to full amortization, so the monthly payment steps up. Pricing floats throughout and never converts to fixed. Plan for the step-up, or plan a refinance, before it arrives.
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. Lendmire is a broker, and every figure here is subject to lender guidelines and full file review, not a commitment to lend.
An ADU is one of the few improvements where the financing has to be planned in the order the cash arrives, and that order is why current equity decides this decision more than anything else.
About Lendmire
Lendmire (NMLS# 2371349) is a mortgage broker. Home equity lines of credit — on a primary residence, a second home or an investment property — are arranged through wholesale lenders in Lendmire’s 16 full-service states, and every line is underwritten by the lender under its program guidelines. Scotsman Guide named Lendmire a Top Mortgage Workplace in both 2025 and 2026.
Get Started
Ready to find the right loan for you?
See your offer in seconds. No credit pull, no obligation.
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. BiggerPockets: ADU build financing
3. Experian: What is a HELOC draw period
4. BiggerPockets: Leveraging equity to finance an STR house hack ADU
5. BiggerPockets: HELOC for ADU exit strategy
This article is part of Lendmire’s bank statement HELOC program — full qualification details, guidelines, and scenarios live on the program page.
Related reading: Can You Get a Bank Statement HELOC When Your Income Is Hard to Document? · 5 Bank Statement HELOC Options to Buy Another Home · Where to Get a Bank Statement HELOC on a Home That Is Paid Off
Brandon Miller
Founder & CEO, Mortgage Loan Originator, Lendmire LLC
- Mortgage Loan Originator · NMLS# 1129696 · Verify on NMLS Consumer Access
- North Carolina Real Estate Broker · License# 343312 · Verify on NCREC
- North Carolina Insurance Producer · License# 19053198 · Property, Casualty, Life, Health · Verify on NAIC SBS
- Lendmire LLC · Firm NMLS# 2371349 · Verify firm licensure
Disclosures. The information presented in this article is general market commentary, not financial, legal, or tax advice. Lendmire is a mortgage brokerage (NMLS# 2371349) — not a direct lender or depository institution — and loan placement is subject to lender underwriting. Nothing in this content represents a commitment to lend. Loan terms, pricing, and program availability vary based on borrower qualifications, property characteristics, and state of subject property, and are subject to change at any time. Lendmire complies with Equal Housing Opportunity requirements. Consumer access: nmlsconsumeraccess.org.