How to Finance Your ADU in Seattle
Compare rates, find local lenders, and discover local grants to fund your backyard cottage or garage conversion in 2026.
Financing Options Comparison
| Loan Type | Rate | Max Amount | Pros | Cons |
|---|---|---|---|---|
| HELOC | 7.5% - 9.5% | Up to 85% LTV | Flexible draws Interest only period | Variable rates Requires current equity |
| Cash-Out Refi | 6.5% - 7.5% | Up to 80% LTV | Fixed rate Single mortgage | Resets 30yr clock High closing costs |
| Construction Loan | 7.0% - 9.0% | Based on future value | Great for low equity Large loan amounts | Complex draws Higher rates initially |
| Home Equity Investment | No Monthly Pmt | Up to $300k | No monthly payments Easy qualification | Give up future appreciation Expensive long-term |
Local Grants & Incentives in Seattle
Seattle Pre-Approved DADU Plans
Pre-approved designs reduce permit fees and review time, indirectly lowering soft costs.
Value: Faster permits + lower feesKing County Housing Authority Programs
Income-qualified homeowners may access subsidized financing for ADUs dedicated to affordable housing.
Value: Varies by programTop ADU Lenders Operating in Seattle
BECU (Boeing Employees Credit Union)
Pacific NW credit union with competitive HELOCs- Rates: From 7.0%
- Max Loan: Up to 90% LTV
Washington Federal
Local construction loans and ADU financing- Rates: From 7.25%
- Max Loan: Subject to LTV
RenoFi
Renovation Loans based on After-Renovation Value- Rates: From 7.25%
- Max Loan: $500,000
Figure
Fast Online HELOC (5-day funding)- Rates: From 7.75%
- Max Loan: $400,000
Hometap
Home Equity Investment — no monthly payments- Rates: No monthly payment
- Max Loan: Up to $600,000
LightStream
Unsecured Home Improvement Loans- Rates: From 7.49%
- Max Loan: $100,000
Compare Seattle ADU loan rates
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