How to Finance an ADU in California: Loans, HELOCs, and State Programs

Building an ADU costs $60,000–$300,000. These are the most practical financing options available to California homeowners in 2025 — including programs most people don't know about.

One of the most common questions we get after homeowners decide they want an ADU is: "How do I pay for it?" Construction costs are real, but so is the return on investment. The good news is that California has more ADU financing options than most states, and home equity in the Central Valley has grown significantly over the past few years.

1. Home Equity Line of Credit (HELOC)

A HELOC lets you borrow against the equity in your home up to a set limit, drawing funds as needed during construction. It's the most flexible option — you only pay interest on what you draw.

• Best for: Homeowners with 30%+ equity and good credit (720+)
• Typical rate: Prime + 0.5% to 2% (variable)
• Draw period: Usually 5–10 years
• Repayment: Interest-only during draw period, then principal + interest
• Advantage: Flexibility — draw what you need as construction progresses

2. Cash-Out Refinance

Replace your existing mortgage with a larger one and take the difference in cash. Works well if your current rate is already competitive or if you need a large lump sum upfront.

• Best for: Homeowners who need the full ADU budget upfront and have significant equity
• Consideration: You'll reset your mortgage term and potentially your rate
• Advantage: One monthly payment, fixed rate available

3. Construction Loan

A short-term loan specifically for building. Funds are released in draws as construction milestones are completed, then converted to a permanent mortgage (construction-to-permanent loan).

• Best for: Larger detached ADU projects where you want dedicated construction financing
• Typical term: 12–18 months construction, then converts to 30-year mortgage
• Lender requirement: Usually requires licensed contractor with fixed-price contract

4. CalHFA ADU Grant Program

The California Housing Finance Agency (CalHFA) has offered pre-development grants of up to $40,000 to cover ADU predevelopment costs: architectural plans, permits, soil reports, and other soft costs. Funds have been limited and competitive — check CalHFA.ca.gov for current availability.

5. Local and County ADU Loan Programs

Several California counties and cities offer low-interest ADU construction loans, often targeting moderate-income homeowners. Programs vary by location and availability. In the Central Valley, check with your county's housing authority for current programs.

6. Personal/Unsecured Loans

For smaller projects like JADUs or garage conversions under $80,000, some homeowners use personal loans. Rates are higher (8–20%) but approval is faster and doesn't require home equity. Works best for shorter payoff timelines.

The ROI Case: Why ADU Financing Often Makes Sense

The math often works in the homeowner's favor — especially with garage conversions in the Central Valley where rental demand is strong. Contact C Hernandez Construction for a free estimate on your ADU project and we can help you understand the real numbers before you talk to a lender.