Accessory Dwelling Units (ADUs)


ADUs - Extra Space, Extra Cash - Property Management ...

Accessory Dwelling Units (ADUs) are becoming increasingly popular as a way for communities to create more affordable living options. Here are a few resources to get you started in thinking about buying, building your own!

The County defines an ADU as, “an additional dwelling unit either in or added to an existing single family detached dwelling, or in a separate accessory structure on the same lot as the main structure, for use as a complete, independent living facility with provisions within the accessory dwelling unit for cooking, eating, sanitation and sleeping.”

The City of Port Townsend allows both the primary residence and ADU to be rented out, whereas everywhere else in Jefferson County, if you are building an ADU on a lot with an existing home, the owner of the single family home must occupy either the primary unit or the ADU if you plan to rent one out.

Learn more about design, permitting, and other ADU guidelines for the City of Port Townsend and Jefferson County.

Build Options


Traditional on-site construction using dimensional lumber.

Commercial Examples

  • Most homes in Jefferson County!


Whole units are built off-site, then delivered and installed. Site work and permitting is still required, as is the interior finish work.

Commercial Examples


Building materials are cut and packaged off-site, and delivered with assembly instructions.

Commercial Examples

Local Advocacy Opportunities

  • ‘Pre-approved ADUs’ are units that have been accepted as well-designed and are permit-able by a municipaltities. This can expedite the ADU process for builders. Jefferson County and the City of Port Townsend are both considering following pre-approved models from Clallam County and the City of Seattle. 
  • The County is considering an update to its ADU policy that would allow for more small units per parcel. Contact Planning Commissioner Matt Sircely at to learn more.