An ADU is a big investment, but you do not have to pay all cash. San Diego homeowners use several ways to finance a backyard home. Here are the most common options and how to think about each.
Common ways to finance an ADU in San Diego
1. Home equity line of credit (HELOC)
A HELOC lets you borrow against the equity in your home as a flexible line of credit. It is popular for ADUs because you draw funds as the project progresses and only pay interest on what you use. Best if you have significant equity and want flexibility.
2. Cash-out refinance
You replace your existing mortgage with a larger one and take the difference in cash to fund the build. This can make sense if current rates are favorable compared to your existing loan. You get a lump sum and a single monthly payment.
3. Home equity loan
A lump-sum loan against your equity with a fixed rate and fixed payments. Predictable and simple, good if you know your total project cost up front.
4. Renovation or construction loans
Renovation loans (such as Fannie Mae HomeStyle or specialized ADU/renovation lenders) base the loan on your home’s projected value after the ADU is built, which can unlock more funds than your current equity alone. Useful if you do not have much existing equity.
5. ADU-specific and contractor financing
Some lenders and builders offer financing designed specifically for ADUs, sometimes with lender-matching built into the build process. Ask each builder what financing partners they work with.
How to choose
- Lots of equity, want flexibility: HELOC.
- Want one fixed payment and a lump sum: home equity loan or cash-out refinance.
- Limited current equity: a renovation loan based on after-built value.
Rates and terms change often, so compare current offers from a few lenders. To estimate how much you need to borrow, start with our San Diego ADU Cost Guide.
Does an ADU pay for itself?
Many San Diego homeowners offset their loan payment with rental income and gain long-term property value. The right financing depends on your equity, the build cost, and your goals.
Get matched with builders who know ADU financing
Several vetted San Diego ADU builders have financing partners and can walk you through your options. Get matched with up to 3 vetted San Diego ADU builders to compare both build costs and financing.
This guide is general information, not financial advice. Confirm current rates and terms with a licensed lender.