ADUs in Redmond, WA
A detached ADU in Redmond costs $310,000 to $500,000 all-in, a garage conversion $120,000 to $215,000 and an attached unit $150,000 to $290,000. Many Redmond subdivision lots have deep rear yards suited to backyard cottages, and the city's employment centers create steady demand for rentals.
Redmond ADU costs
| ADU | Typical Redmond range | Redmond factors |
|---|---|---|
| Detached ADU | $310,000 – $500,000 | Yard depth, buffers, utilities |
| Garage conversion | $120,000 – $215,000 | Attached garages need fire separation |
| Attached or basement ADU | $150,000 – $290,000 | Daylight basements in Overlake |
How state ADU law applies in Redmond
Washington law requires Redmond to allow at least two ADUs on most residential lots, with no owner-occupancy requirement and with limits on parking requirements and impact fees. Redmond's code sets size, height and placement standards. Check the current rules for your lot.
What Redmond lots bring to an ADU
Deep yards on Education Hill and in North Redmond can fit a cottage behind the house with room to spare.
Stream and wetland buffers behind many lots can remove the rear yard from use. Check the city's maps before design.
HOAs. Private covenants may still contain restrictions; state law changes what the city can require, not necessarily what a covenant says. Read yours and get legal advice if it appears to bar an ADU.
Utilities. Sewer and water connections are reviewed by the utility; distance and grade affect cost.
Redmond ADU permits
An ADU needs a building permit with drawings, energy compliance and utility plans through MyBuildingPermit, plus trade permits and often tree and stormwater review.
Redmond ADU questions
Can I build a backyard cottage on my subdivision lot?
Often, if setbacks, buffers and utilities allow. Lot depth helps.
Is a garage conversion the cheapest option?
Usually, if the garage is sound. Attached garages need a rated wall to the house.
Will my HOA covenants stop an ADU?
Possibly. Covenants are private agreements; review them with an attorney.
How long does a Redmond ADU take?
Twelve to eighteen months for a detached unit, eight to twelve for a conversion.