Using Rental Income to Qualify for a Mortgage: A Sacramento Buyer’s Guide
Yes — lenders will often let you use rental income to help you qualify for a mortgage, whether it comes from a multi-unit property, an ADU, a room you rent out, or the home you’re moving out of. But they don’t count all of it. Most loan programs use about 75% of the rent (a 25% “vacancy factor”), and the income usually has to be backed by a lease or an appraiser’s market-rent estimate. Used right, it’s one of the most powerful ways to stretch your buying power in the Sacramento market.
The 75% rule (why lenders “haircut” your rent)
Lenders know rentals aren’t income 100% of the time — there are vacancies, repairs, and the occasional late payment. So instead of counting the full rent, most programs count about 75% of it. If a unit rents for $2,000 a month, the lender typically credits you with $1,500 toward qualifying. That 25% cushion is the single biggest thing buyers get wrong when they run their own numbers.
Four ways to use rental income in Sacramento
1. The multi-unit house hack (2–4 units)
Buy a duplex, triplex, or fourplex, live in one unit, and rent the others. Because you live there, you get owner-occupied financing — as little as 3.5% down on FHA or low-down conventional — and the projected rent from the other units (estimated by the appraiser) can count toward your qualifying income. It’s the classic first step to building a rental portfolio while someone else helps pay your mortgage.
2. ADU income
Sacramento’s ADU boom opened a door: on a single-family home with a permitted accessory dwelling unit (a granny flat or casita), conventional guidelines now allow you to use a portion of that ADU’s rental income to help you qualify — even on a primary residence. If you’re buying a home that already has an ADU, that’s real qualifying power most buyers don’t realize they have.
3. Your departing residence
Moving up but want to keep your current home as a rental? With a signed lease (and sometimes a check on your equity or reserves), lenders can count that rental income so the old mortgage doesn’t sink your ability to qualify for the new one. This is how a lot of Sacramento families turn their starter home into their first rental instead of selling it.
4. Boarder or roommate income
Renting out a room? Certain programs (like HomeReady) let you count boarder income toward qualifying when you can show a history of receiving it. It won’t move the needle as much as a full unit, but for the right buyer it’s the difference between approved and not.
Income source
What you need to document
Roughly how much counts
Multi-unit (2–4) you’ll live in
Appraisal market-rent schedule (Form 1025)
~75% of market rent
ADU on a primary residence
Lease and/or appraiser market rent
Portion of rent per guidelines
Departing residence rental
Signed lease; sometimes equity/reserves
~75% of lease rent
Boarder / roommate
History of payments + documentation
Per program (e.g., HomeReady)
A Sacramento example
Say you buy a duplex in the Sacramento area, live on one side, and the other side rents for $1,900 a month. At the 75% factor, the lender credits you with about $1,425 a month of qualifying income. That added income can lift the loan amount you qualify for by tens of thousands of dollars — while a tenant covers a big chunk of your payment. That’s the house-hack math in one move.
What you’ll need to have ready
• An appraisal with a market-rent estimate (Form 1007 for a single unit, Form 1025 for multi-unit).
• Signed leases for any unit or home that’s already rented.
• Tax returns (Schedule E) if you already own rental property.
• Proof of reserves — some scenarios require a few months’ payments in the bank.
Frequently Asked Questions
How much rental income can I actually use?
Most programs count about 75% of the rent, holding back roughly 25% for vacancy and upkeep.
Can I use rent on a home I haven’t rented out yet?
Often yes — for a property you’ll occupy with extra units or an ADU, an appraiser can estimate market rent that counts toward qualifying, even before a tenant moves in.
Does ADU income really count?
On a primary residence with a permitted ADU, conventional guidelines now allow a portion of that rental income to be used. The exact treatment depends on the program.
Can I keep my current home and rent it out?
Yes. With a signed lease — and sometimes a look at your equity or reserves — lenders can count that income so your existing mortgage doesn’t block the new loan.
Do I need to already be a landlord?
No. For an owner-occupied multi-unit or an ADU purchase, you can use projected rent without any prior landlord history.
Want to see how much a tenant could add to your buying power?
Whether it’s a duplex, a home with an ADU, or keeping your current place as a rental, the numbers are usually better than buyers expect — once you account for the 75% rule the right way. A quick call can map out exactly what you’d qualify for.
Call or text (916) 794-0777 • thechriskennedyteam.com
Chris Kennedy | The Chris Kennedy Team | NMLS #971546
Serving Sacramento, Placer, El Dorado & Yolo Counties