A duplex, triplex, or fourplex is small multifamily: one property, two to four rental units, one loan. A DSCR loan on one of these generally weighs eligible rent from the whole property against a single qualifying PITIA payment, meaning principal, interest, taxes, insurance, and association dues added together each month. The ratio itself is the one you would run on a single-family rental. The evidence under it is what multiplies. Every unit brings its own rent proof, lease status, condition, utility responsibility, and vacancy risk. Confirm the DSCR program accepts the property type before you order the appraisal. An ineligible property still costs you the fee.
Diversified rent is still thin rent at this size. A fourplex stands on four legs, a duplex on two, and losing one leg of a duplex tips the table hard: a single vacancy can take out 25% to 50% of scheduled rent. Run the property-level ratio in the DSCR calculator, then run a separate cash-flow stress test with one unit empty.
Worked duplex example: what one vacancy does
Unit A rents for $1,400, Unit B for $1,300. With both occupied the property collects $2,700 a month against a $2,250 PITIA. Divide $2,700 by $2,250 and you get 1.20x coverage, or $1.20 of rent for every dollar of payment. Now empty Unit B. Collections drop to $1,400, the payment stays $2,250, and coverage falls to 0.62x, which is not even two-thirds of the payment, before a dollar of repairs, utilities, or management.
| Scenario | Unit A rent | Unit B rent | Rent collected | PITIA | Coverage |
|---|---|---|---|---|---|
| Both units occupied | $1,400 | $1,300 | $2,700 | $2,250 | 1.20x |
| Unit B vacant | $1,400 | $0 | $1,400 | $2,250 | 0.62x |
These figures are illustrative. A lender's qualifying method may still count supported market rent on a vacant unit, so the file can qualify while your bank account feels the hole. The lender is underwriting what the property could earn. You are living on what it actually collects. Plan for both.
Document every unit separately
The appraiser and the underwriter assemble the property total out of unit-level facts. Gather them per unit, not per building:
- The current lease and any amendments, with start and end dates, monthly rent, concessions, deposits, and payment history.
- Occupancy status, and the date any vacant unit came open.
- Bed and bath count, square footage, condition, parking, storage, appliances included.
- Which utilities are separately metered, and which bills stay with the owner.
- Whatever legal-unit, permit, zoning, or certificate-of-occupancy paperwork the lender or appraiser asks for.
Your deal
See if your deal qualifies.
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Check my DSCRWhat the appraisal and rent report cover
In Fannie Mae's conventional framework, Form 1025 is the Small Residential Income Property Appraisal Report for two- to four-unit properties, and it carries unit information and an income analysis. A DSCR lender may order Form 1025 or a different appraisal scope, and its eligible-rent calculation may differ from Fannie Mae's conventional 75% treatment. Eligible rent is just the rent the lender agrees to count, which is how one building produces different qualifying numbers at different lenders. Ask what will be ordered, and how vacant, owner-used, or below-market units get handled.
Qualification commonly runs total eligible property rent over the property's qualifying PITIA, with unit-level evidence propping up that total, so use the selected lender's exact formula rather than this one. A tenant in every unit before closing is not always required. The lender may work from leases, supported market rents, or some mix of the two, subject to vacancy and property-condition rules. Confirm how each vacant unit gets treated before you count on its projected rent.
Expenses can differ from a single-family rental
- Common-area electricity, water, sewer, trash, landscaping, snow removal, and pest control can all stay with the owner.
- Insurance and replacement cost move with unit count, property configuration, and local risk.
- Turnover comes around more often, since each unit runs its own lease cycle.
- Shared roofs, foundations, mechanical systems, driveways, and utility lines concentrate the capital spending. One roof covers every unit's income at once.
Do not confuse investment occupancy with house hacking
A business-purpose DSCR loan is meant for non-owner-occupied investment property. Move into one unit and the occupancy facts change, which may point to a consumer mortgage program instead, so state intended occupancy accurately and compare owner-occupied small-multifamily options if house hacking is the plan. A fifth unit ends the conversation: five or more units are generally treated as commercial multifamily rather than one-to-four-unit residential property, with different appraisal, underwriting, and loan structures.
Verify every lease, meter, unit condition, and owner-paid expense on your own deal, then stress one vacancy and one major repair before you decide the building carries the debt. If the deal only works with every unit full and nothing breaking, you have your answer about how fragile it is.
The property-level ratio decides coverage. The unit-level facts decide whether the rent lasts.
The form numbers are mid-transition. Appraisals submitted to the GSE portal on or after November 2, 2026 use a single dynamic URAR that swallows Form 1025, with the market-rent estimate becoming a section inside it. DSCR loans are business-purpose and never touch that portal, so a non-QM lender can go on asking for the legacy form by name past that date while the appraiser it hires has already moved to the new report. Ask both sides what will actually be delivered before ordering. The appraisal article walks through the collision.
One federal definition now splits duplexes from triplexes and fourplexes. The 21st Century ROAD to Housing Act defines a single-family home as a structure with two or fewer dwelling units, so a duplex sits inside its institutional-investor purchase limit while three- and four-unit properties sit outside it. The limit binds only entities controlling 350 or more such homes, which is nobody buying a first small multifamily. It still matters if you are aggregating across affiliates, or counting on an institutional buyer for your exit. The ROAD Act article covers the tests.
- IRS Publication 527: Residential Rental Property →
- How the appraisal rent report works →
- What DSCR is and how it works →
- The insurance premium, coverage, and deductible test →
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