Your Guide to Accessory Dwelling Units (aka ADUs or DADUs)

Have you been considering an "in-law" apartment or backyard cottage? This type of dwelling is technically referred to an accessory dwelling unit aka "attached dwelling unit" (ADU) or detached dwelling unit (DADU).

An ADU is a smaller living space on the same lot as a single-family home. It must be a habitable living unit including space for sleeping, cooking and a bathroom with it's own entrance (independent of the primary residence). An ADU could be an apartment over the garage; in the basement of the primary residence; a detached home in the back yard; or even a manufactured home.

Recent changes to zoning laws in Washington state allows more homes to have an ADU. In many areas, regulations for ADUs have been eased to help promote the addition of accessory dwelling units in the spirt of creating more affordable housing.

Adding an ADU to your home can provide a lot of options, including increase value by adding more living space. An ADU also provides additional space for when family or friends come to visit; or if you need housing for a parent or adult children. They can also provide additional income as an investment property or short-term-rental. Rental income may be factored for qualifying purposes.

There are several options available for financing an ADU/DADU, including:

  • Conventional Home Renovation
  • FHA
  • FHA 203(K)
  • VA
  • One-Time Close Construction Loan
  • Home equity lines of credit or fixed rate second mortgages.
  • Reverse Mortgage

Financing is available for purchases or refinances.

Different down payment (home equity) requirements are based on the occupancy (primary, second home or investment property). Some programs, like FHA, have minimum down payment options.

The property must meet zoning requirements. Some cities actually have pre-approved DADU plans to help make the permit process more efficient, including:

Here are guides from other cities information regarding ADUs:

If you are considering adding an ADU/DADU to your home or finding a new home with the potential to add an apartment, please reach out to me! I am happy to review possible options with you.


"Communication was exemplary! She went above and beyond to help make sure this was a successful transaction for all parties involved. Looking forward to many more transactions with Rhonda!"

deanna f

"Process was very smooth and very informative throughout, which I appreciate greatly as I had a ton of questions!"

vincent r

"To begin, we were moving across country with short notice and the seller required a 30-day closing. I haven’t experienced getting a mortgage in over 30-years…OMG it’s changed a lot! I am not even exaggerating when I say that we would not have accomplished this without the exceptional experience that Rhonda brought! After we signed and locked the 2023 high interest rate, days later there was a significant dip in the rates and Rhonda relocked us at the lower rate! What an unexpected gift. I don’t know anyone else who would go out of their way to do that for a client. Not only is she a Pro, but she’s a joy to work with and also guided us through with lots of patience. 5-STARS all the way!"

mark fernandez