Using ADU Rental Income to Qualify for a Mortgage in California

I’m Michael DiVita (DRE #01372066 | NMLS #241655), owner of DiVita Home Finance (DRE #01818285 | NMLS #323700) in Tiburon, CA. I’ve been in California mortgage lending since 2000 and founded DiVita Home Finance in 2007. I’m known as a creative mortgage broker: when a bank says no, I find the lender and the loan structure that can say yes. ADU rent is one of the most useful — and most misapplied — qualifying tools I see. Call (800) 239-1103.

Yes, you can use rental income from an accessory dwelling unit (ADU) to qualify for a mortgage on a one-unit home you’ll live in. Fannie Mae, Freddie Mac and FHA all allow it, generally on purchases and rate-and-term refinances, with the ADU income capped at 30% of your total qualifying income and only one ADU counted. Lenders typically count about 75% of the rent to allow for vacancy and expenses, so a $2,000-a-month ADU adds roughly $1,500 of qualifying income — enough to support about $100,000 more loan at current rates.

ADU Income Rules by Loan Type (2026)

Before these changes, Fannie Mae allowed ADU income mainly through HomeReady. Now the rules are broader, but not every lender has adopted every option, and lender overlays vary. That’s where shopping lenders helps.

How Much Does ADU Income Help?

Lenders generally count about 75% of the ADU’s rent, based on a lease and/or the appraiser’s market rent schedule. Two examples at a 7% 30-year fixed rate:

• $2,000/month rent → about $1,500 of qualifying income → roughly $97,000–$113,000 more loan, depending on whether your debt-to-income limit is 43% or 50%.
• $2,400/month rent → about $1,800 of qualifying income → roughly $116,000–$135,000 more loan.

The 30% cap matters for lower-income households. If your other qualifying income is $10,000 a month, the most ADU income you can count is about $4,285 a month (30% of the $14,285 total).

The ADU Has to Be the Real Thing

An ADU for lending purposes is a separate living unit with its own kitchen, bathroom and entrance. Lenders and appraisers will look at:

• Permits and zoning. A permitted ADU with a final inspection is the clean case. An unpermitted garage conversion usually can’t be counted for income, and it can complicate the appraisal. Freddie Mac has a narrow exception for some non-conforming ADUs on one-unit properties, but don’t plan around it. Pull the permit history before you write an offer.
• Junior ADUs (JADUs). A JADU inside the main house under California law may or may not meet a lender’s ADU definition, depending on its kitchen, bath and entrance setup. Ask before you count it.
• Completion. Rent from an ADU that isn’t built yet generally can’t be used on a standard purchase loan. FHA’s 203(k) program has the new-construction rule above; renovation and construction financing is covered on my ADU financing page.
• Short-term rentals. ADUs created under California’s by-right rules can’t be rented for 30 days or less, and conventional lenders generally need a documented history before counting short-term rental income.

Buying a Home With an Existing ADU

1. Confirm the ADU is permitted and meets the lender’s definition.
2. Get the current lease and rent history if it’s tenant-occupied, and ask the seller about tenant rights under California law.
3. I’ll order an appraisal with a comparable rent schedule so the market rent is documented.
4. We’ll calculate qualifying income with and without the ADU so you know exactly what it adds.

In expensive markets like Marin and San Francisco, ADU income can be what makes a high-balance conforming loan work instead of a jumbo — see jumbo vs. conforming.

Already Own and Just Built an ADU?

Once the ADU is finished, permitted and rented, a rate-and-term refinance can use its income to help you qualify (Fannie Mae allows limited cash-out refinances; FHA doesn’t allow ADU income on cash-out refinances). If you financed construction with a HELOC or construction loan, that refinance is often the exit.

Self-Employed or Several Rentals?

If your tax returns understate your income because of write-offs, a bank statement loan qualifies you on deposits instead. Investors buying properties with ADUs can use DSCR loans that qualify on rent.

Frequently Asked Questions

Can I use ADU rental income to qualify for a mortgage in California?

Yes. Fannie Mae, Freddie Mac and FHA allow ADU rental income on a one-unit home you’ll live in, capped at 30% of your total qualifying income and limited to one ADU. Lenders typically count about 75% of the rent.

Does the ADU need a tenant for the income to count?

Not always. Rent can be supported by the appraiser’s market rent schedule and/or a lease, depending on the program and lender. FHA counts only 50% of market rent when there’s no rental history. Ask your lender which documentation it requires.

How much more can I borrow with ADU income?

Roughly $100,000 of additional loan for every $1,500 of monthly qualifying income at a 7% rate, depending on your debt-to-income limit. A $2,000-a-month ADU at 75% adds about $1,500 of qualifying income.

Can I count income from an unpermitted ADU?

Generally no. The unit usually needs to be legal and permitted, and an unpermitted unit can create appraisal problems. Check the permit history before relying on the income.

Can I use ADU income on a cash-out refinance?

Not with FHA. Fannie Mae allows ADU income on purchases and limited cash-out refinances, and Freddie Mac on purchases and no-cash-out refinances.