Does the rent from an ADU count toward my loan?
Yes, within a cap. A house with one legal ADU (a garage apartment, basement unit or backyard cottage) is financed as a one-unit home. FHA and Fannie Mae can count 75 percent of the ADU's rent, up to 30 percent of the total income they count for you.
WHAT MOST PEOPLE ARE NEVER TOLD
The appraiser decides whether a home is a house with an ADU or a duplex, whatever the listing says. That label sets which rent rule applies.
A duplex has no cap like that. A house with an ADU is a one-unit home on paper, and that brings its own rules. From FHA's handbook and Fannie Mae's main guide, read November 2026:
- One ADU: on a conventional loan, Fannie Mae counts rent from one existing ADU only.
- Its own door: for Fannie Mae, an ADU needs its own kitchen and bathroom, and a way in that does not pass through the main house.
- Cash after closing: FHA asks for two months of payments in reserve if you use the ADU's rent. Fannie Mae's software sets no fixed minimum on a one-unit home, though it can still ask for some. On a duplex it asks for six months.
The cap is a share of your income, so the ADU rent that can count rises with what you earn. Under FHA, a duplex plus an ADU is a three-unit home. That brings in FHA's test of whether the rent covers the payment (the self-sufficiency test).
GOOD TO KNOW
Ask the city's permit office whether the ADU was permitted and whether you may rent it, before you count the rent. On an FHA loan the ADU has to fit zoning, and the appraiser gives a rent figure only if it can be legally rented without restrictions.
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WHERE THIS COMES FROM
- HUD Mortgagee Letter 2023-17 (October 16, 2023), Revisions to Rental Income Policies, Property Eligibility, and Appraisal Protocols for Accessory Dwelling Units
- HUD Handbook 4000.1 (revised August 12, 2026): property types, II.A.1.b.iv(B); ADU rent, II.A.4.c.xii(I); reserves, II.A.4.d.i(C); ADU appraisal, II.D.3.b.vii(E)
- Fannie Mae Selling Guide B3-3.8-02, Rental Income from the Subject Property (September 2, 2026)
- Fannie Mae Selling Guide B2-3-04, Special Property Eligibility Considerations: Accessory Dwelling Units (November 4, 2026)
- Fannie Mae Selling Guide B3-4.1-01, Minimum Reserve Requirements
Researched and written by Series Homes. Checked against its sources on . Lending rules change. This page is general information, not a loan offer or legal or tax advice.