ADU financing
How to finance an ADU in 2026.
Almost no one pays cash for an ADU. The right product depends on your existing mortgage rate, your equity, and whether you're refinancing simultaneously. Below is each financing path explained, with rate ranges, application processes, and the situations where each one actually wins.
Financing products
ADU HELOC
Prime + 0.5% to 2% variable (Dynamic Quality Builders 2026) — landing roughly 8–10.5% in mid-2025/2026 conditions
Read the guide
ADU Construction Loan
Prime + 1–3% variable during construction (Better Place Design Build 2025) — roughly 8.75–11.5% in current conditions; permanent-phase rate locks at conversion
Read the guide
ADU Renovation Loan
Roughly 7–9.5% in mid-2025/2026 conditions (close to standard mortgage rates) — lower than HELOC and construction-loan rates
Read the guide
ADU Grants
N/A — grants don't carry interest
Read the guide
California ADU Grant Program
N/A — grant, not a loan
Read the guide
FAQ
- What's the best way to finance an ADU?
- It depends on three things: your existing mortgage rate, how much equity you have, and whether you're refinancing simultaneously. HELOC wins when your first mortgage rate is low and you have substantial equity. Renovation loans (FHA 203k or Fannie HomeStyle) win when you're buying or refinancing alongside building. Construction loans win when you don't have HELOC capacity and need staged draws.
- Can I use rental income from my future ADU to qualify for a loan?
- Yes — as of 2024, Fannie Mae and Freddie Mac formally allow lenders to factor projected ADU rental income into loan qualification using a fair-market-rent schedule (1007 form). Ask any lender: 'Do you underwrite ADU rental income on the appraised value?' If yes, you can qualify for a larger loan.
- Are there grants for building an ADU?
- Limited and cycle in and out. California's CalHFA ADU Grant historically offered up to $40,000 — currently paused since December 2023. Washington state has a $25,000 program in some counties. Most California cities waive impact fees on ADUs under 750 sq ft, which functions as a soft grant.
Get sourced ADU financing updates monthly
Rate ranges and grant status change quarterly — we re-validate.