A second living space can add real rent to a property. Whether a lender counts that rent toward your DSCR depends on permits, zoning and what the appraiser can support.
In short: LendingStreet finances rental properties with an ADU, in-law suite or garage apartment through our DSCR programs, with up to 80% LTV on purchases and a 620 minimum credit score. Whether the ADU's rent counts toward the ratio varies by program. It is most often counted when the unit is legal and permitted and the appraisal supports its rent with comparable data. If the ADU is unpermitted or the appraiser cannot support it, expect the loan to be sized on the main house rent alone. Some properties with a second unit are treated as a 2-unit property instead.
An accessory dwelling unit is a second, smaller living space on the same lot as a main house. It may be attached, like a basement apartment or in-law suite, or detached, like a backyard cottage or apartment over a garage.
Lenders generally look for a complete living unit: its own entrance, a kitchen, a bathroom and a sleeping area. A finished basement with a wet bar is usually just more living space in the main house, not an ADU.
Programs differ, so treat these as common patterns rather than fixed rules. The more of these boxes you can check, the more likely the ADU income counts.
Many in-law suites and garage apartments were added without permits. An appraiser will often note an unpermitted unit, and many programs will then give it no rent credit. Some will not lend on the property at all if the unpermitted space raises safety or zoning concerns.
Before you buy, ask the seller for permit records, or check with the local building department. If the ADU was never permitted, ask what it would take to legalize it. That cost and timeline belong in your deal analysis.
A property can look like a house with an ADU but be recorded or zoned as a duplex. Or a local rule may treat a second full unit as a separate dwelling. When that happens, the appraiser may complete a 2-to-4-unit report and the loan is reviewed as a 2-unit property.
That is not necessarily worse. On a 2-unit, both units' rents are normally part of the qualifying income. The appraisal and the zoning will decide which category applies, and our 2-to-4 unit DSCR page covers that side.
| Setup | Usual review | Second-unit rent in DSCR |
|---|---|---|
| Permitted ADU on a single-family lot | Single-family with ADU | Often, if the appraisal supports it |
| Unpermitted in-law suite or garage apartment | Single-family | Often not counted; varies by program |
| Property zoned or recorded as two units | 2-unit property | Normally yes |
This example is illustrative and not a quote. An investor buys a house with a permitted detached garage apartment for $420,000. The appraisal shows market rent of $2,300 for the main house and $1,100 for the ADU.
At 75% LTV, the loan is $315,000. At a sample rate of 7.5% on 30-year amortization, principal and interest is about $2,203. Adding $550 a month for taxes and insurance brings the payment to about $2,753.
If the ADU rent counts, qualifying rent is $3,400 and DSCR is about 1.24x. If only the main house rent counts, DSCR is about 0.84x, below the 1.0x standard minimum. On that version, the investor would need a larger down payment or a sub-1.0 DSCR program. This is why the permit question matters before you make an offer.
If you are building an ADU on an existing rental, the new rent usually is not counted until the unit is finished, permitted and supported by an appraisal. Many investors fund the build with cash or short-term financing, then do a DSCR refinance once the unit is complete and leased.
Ground-up construction financing is available for larger projects, and our construction-to-DSCR guide explains the build-then-refinance path.
Along with entity documents, bank statements for reserves and leases, gather the records that prove the ADU is legal and rentable. Our financing team can review them before you commit and come back with 2–3 options if the file qualifies.
It varies by program. ADU rent is most often counted when the unit is permitted, zoning allows it to be rented and the appraisal supports its market rent. Otherwise the loan is usually sized on the main house rent.
Often yes, but the in-law suite's rent will likely not count, and the appraiser may give it little or no value. Some programs decline properties where the unpermitted space raises safety or zoning issues.
Not always. It depends on zoning and how the property is recorded. If it is legally two units, it is usually reviewed as a 2-unit property, and both rents normally count.
Not with a DSCR loan. LendingStreet finances non-owner-occupied investment property only. If you will live in any part of the property, you would need a consumer mortgage lender.
Not necessarily. A separate address or meter can help show it operates as its own unit, but requirements vary by program and by city.
Yes, in many cases. Once the ADU is finished, permitted and leased, a DSCR refinance may count its rent if the new appraisal supports it.
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