Bay Area ADU Loan Calculator
The Bay Area has the highest ADU build costs in the country and some of the highest achievable rents. Use this calculator to compare HELOC, construction-perm, and cash-out refi monthly payments on a realistic Bay Area build.
Enter your project details
Loan amount: $288,000
HELOC
Variable rate, interest-only draw option
Flexible line of credit. Only pay interest on what you draw.
Construction-Perm
Draws during build, converts to mortgage
Funds disbursed by milestone. Permanent loan activates at completion.
Cash-Out Refi
Replaces your current mortgage
Combines existing mortgage + ADU cost into one new 30-year loan.
Rent-coverage estimate
Typical ADU rent in the West Coast region runs about $2,600/mo. That covers roughly 112% of the featured HELOC monthly payment shown above.
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Active ADU financing programs in California
Local City ADU Incentives
waiverMany California cities (Los Angeles, San Diego, San Jose, Oakland) waive or reduce impact fees, school fees, or utility connection fees for ADUs. Check your municipality's ADU program for current offers. Note: the statewide CalHFA ADU Grant Program closed to new applications in December 2023 after all funds were allocated.
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ADU loan product comparison
| Product | Typical rate | Term | Best for |
|---|---|---|---|
| HELOC | 7.5–10.5% variable | 10 draw + 20 repay | Homeowners with 20%+ equity who want flexibility |
| Home Equity Loan | 7.3–10.3% fixed | 10–30 yr | Borrowers who want a fixed monthly payment |
| Cash-Out Refi | 7.5–8.5% fixed | 30 yr | Current mortgage rate already near market |
| Construction-Perm | 8.0–12.0% | 12–18 mo then 30 yr | Ground-up builds over $200K |
| DSCR | 8.5–12.0% | 30 yr | Investors qualifying on rent |
| RenoFi | 8.0–11.0% | 10–20 yr | Limited current equity, new-build ADUs |
Frequently asked questions
How do I get an ADU loan in the Bay Area?
Start by pulling a recent appraisal to confirm your usable equity. Then get quotes from 2–3 lenders — local credit unions often beat national banks on HELOC rates, while a national construction lender may be the only option for a ground-up build. Use the calculator above to compare a HELOC, cash-out refi, and construction-perm payment on the same build cost.
What does an ADU cost in the Bay Area?
the Bay Area ADU builds typically run $250,000–$550,000 all-in. Detached units with full kitchens and utility hookups fall in the upper half of that range, while garage conversions and attached units come in lower.
Will the Bay Area ADU rent cover the loan payment?
Detached ADUs in the Bay Area typically rent for $2,800–$3,600 per month. Against a $200,000 HELOC at current rates, that rent covers 80–110% of the monthly payment in most configurations — meaning the unit usually cash-flows or comes close.
What ADU lenders serve the Bay Area?
National lenders (Figure, RenoFi, LightStream) lend in every state. Local California credit unions and community banks often offer the lowest HELOC rates for the Bay Area homeowners. The lender-match CTA on this page connects you with three California lenders that specialize in ADU financing.
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