How to Finance an ADU in California — All 7 Options Compared
Most California homeowners don't have $250K cash sitting around to build an ADU. The good news: ADUs unlock several financing structures that don't exist for general home improvements, because lenders treat them as appraisable income-producing additions. Here are the seven real options, what they actually cost, and which one fits your situation.
HELOC rate (2026): ~8.5–9.5%
Construction loan: ~9–10.5%
CalHFA grant: Up to $40K
Typical down: 0–20%
What this guide covers
Each section below answers one part of the question in plain language, with 2026 Sacramento-region numbers rather than national averages.
1. HELOC (home equity line of credit) — The most common ADU financing tool.
2. Cash-out refinance — Refinance your existing mortgage for a higher amount and take the difference in cash.
3. Construction-to-permanent loan — A single loan that funds construction in draws and converts to a long-term mortgage when the ADU is complete.
4. CalHFA ADU Grant — $40,000 free money — California's CalHFA Grant covers up to $40,000 in soft costs (design, permits, impact fees, utility connections) for qualifying homeowners.
5. Renovation loans (Fannie Mae HomeStyle, FHA 203k) — Government-backed renovation loans roll the cost of the ADU into a single mortgage based on as-completed value.
Frequently asked: How to Finance an ADU in California (2026)
The questions homeowners ask most about this topic, answered by a CSLB-licensed Sacramento builder.
Can I get a loan to build an ADU? Yes. The most common options are a HELOC against your existing home equity, a construction-to-permanent loan that funds the build and converts to a mortgage, a renovation loan like Fannie Mae HomeStyle, or a cash-out refinance. Specialty ADU lenders like RenoFi also write loans against the ADU's projected appraised value.
What is the best way to finance an ADU in California? For most homeowners with equity, a HELOC offers the lowest cost and most flexibility. If you have limited equity but strong income, a construction-to-permanent loan based on the as-completed appraised value is usually the better choice. If your household income is at or below 80% AMI, stack the CalHFA $40K grant against either.
Do banks loan money for ADUs? Yes. Most large banks (Chase, Wells Fargo, U.S. Bank) offer HELOCs that can fund ADUs. Local credit unions like Golden 1 and SchoolsFirst Federal Credit Union are often more competitive on construction-to-permanent loans. Specialty lenders (RenoFi, Acorn) focus specifically on renovation and ADU financing.
How much equity do I need to finance an ADU? For a HELOC, you typically need at least 20% equity remaining after the line is drawn. For a $250K ADU on a property with a $500K mortgage and $900K value, that means a HELOC up to ~$220K is feasible. Construction-to-permanent loans let you borrow against the projected as-completed value, so less current equity is required.
How we deliver How to Finance an ADU in California (2026)
Every project runs through the same five-stage process, so you know what happens next and what it costs before construction starts. We handle design, engineering, jurisdictional plan check and construction under one contract, which keeps the schedule and the budget with a single accountable team.
Stage 1 — Site walk and feasibility: setbacks, utilities, easements and lot coverage reviewed on site
Stage 2 — Fixed-scope proposal: line-item pricing with permits, utility connections and finishes included
Stage 3 — Design and engineering: architectural plans, Title 24 energy calcs and structural engineering
Stage 4 — Permitting and plan check: submittal, corrections and approvals handled by our office
Stage 5 — Construction and closeout: weekly updates, final inspection, certificate of occupancy and warranty
Why homeowners choose A1 for How to Finance an ADU in California (2026)
A1 Building Contractors LLC is a veteran-owned, CSLB-licensed general contractor based in Roseville, CA. We design, permit and build ADUs, garage conversions, home additions and custom homes across the Sacramento region, with transparent line-item pricing and a single point of contact from first site walk to final inspection.
CSLB #1094366 General Contractor · DRE #00898265 Broker
Serving Sacramento, Placer, El Dorado, Yolo and Sutter counties
In-house design, permitting, plan check and construction
4010 Foothills Blvd Ste 103-155, Roseville, CA 95747