Is an ADU a Good Investment?
By Eric Dexter, Owner & Builder ·
For a lot of Seattle-area homeowners, yes — an ADU is one of the better returns you can get on land you already own. It's not a get-rich-quick move, but between rental income and added property value, a well-built DADU tends to pay for itself over time while giving you flexibility along the way. Here's how to think about the return.
The three returns of an ADU
An ADU pays you back in three ways at once: monthly rental income, a higher property value, and the option to use the space yourself (family, office, aging in place). Even if you never rent it, the added value and flexibility are real.
Rental income
In a high-rent market like Seattle, a detached backyard home can command meaningful monthly rent, and many owners put that rent straight toward the loan they used to build. That's the engine of the ROI — an income stream on a property you already have. Some financing even lets you factor projected rent into what you qualify for; we cover that in how to finance an ADU.
Added property value
A permitted ADU adds legal, independent square footage — which generally raises your home's market value and appraisal. In a market where buyers prize income potential and flexible space, a home with a legal ADU stands out. We go deeper in what an ADU means in real estate.
What's the payback period?
It depends on your build cost and your rent. A DADU in the Seattle area typically runs $375,000–$600,000+ all-in, and rent varies by size and neighborhood — so payback is measured in years, not months, and the added home value counts toward the return from day one. The honest way to size it up is with real numbers: estimate your build with the ADU cost calculator and compare it to local rents.
What shapes your ROI
- Build cost — mostly driven by site difficulty and finish level
- Rent rate — size, location and quality of the unit
- How you use it — full-time rental vs. family use vs. a mix
- Financing terms — your rate and loan structure
Run your own numbers
The best way to know if an ADU pencils out for you is to price a real build on your lot, then weigh it against rent and added value. Start with the calculator, then talk to us — we'll give you honest figures your numbers can stand on.