If we want more Accessory Dwelling Units, we need to make it easier to build them

Accessory Dwelling Units (also known as Secondary Dwelling Units, Granny Flats, Mother-in-Law Units, Garage Apartments, or Backyard Cottages), are smaller homes that share a lot (and sometimes even a building!) with a detached, single family home.  ADU’s  can range in size from Tiny Homes  (250 square feet or less)o to units large enough for  a single family (800-1000 square feet.)  Accessory Dwelling Units are primarily used either as housing for extended family or as rental units.

Some common forms of ADU’s  include:

  • Attached or Interior Accessory Dwellings: These ADU’s are part of the primary home. They might be located in a basement, or a garage, or an upper floor. They often have a separate entrance, but share a wall and roof with the main house. Unlike a “room to rent”, an ADU has its own kitchen and bathroom facilities.

  • Backyard Cottages: These are separate homes, typically located in the yard They are usually studio or one (perhaps two) bedroom units, and are basically just a smaller version of a traditional home.

  • Garage Apartments: These are apartments incorporated into a separate building on the property that also serves another use--for example, a detached garage with an apartment above it.

Besides providing needed housing, ADU’s offer several advantages to property owners.  These include:

  • Extra income from a rental property.

  • Adaptability to Family Needs—For instance, an ADU can provide housing for adult children just starting out in the world, or aging parents who wish to be close but maintain independence

  • Security—a “built-in neighbor” can offer assistance to an aging or single homeowner in case of trouble.

  • Flexibility—Older adults looking to downsize might simply move from their main home into the ADU, while young adults might move from the ADU into the main house when they start a family.

For tenants, ADU’s make many of the advantages of a single-family home available to those who either can’t afford or don’t want to own one.  These might include a location in a desired neighborhood, access to good schools and parks, and a small yard or garden space

Because they make use of land already bought and paid for, new ADUs can sometime provide less expensive housing than other new construction.  While the rent for a new ADU would have to include the cost of system development charges, permitting and fees, financing charges, and construction or renovation costs, they are a prime way for “incremental” development.  This means individual, local property owners are adding small amounts of housing for the benefits of themselves and their neighbors.

Current Conditions involving ADU’s in Eugene:

  • ADUs are allowed in Eugene’s low-density (R-1), but face restrictions. There are additional restrictions in a few specific neighborhoods (Amazon, Fairmount and South University). A homeowner must determine which restrictions apply to his/her particular location, and then design an ADU that complies with the relevant restrictions.

  • The homeowner must sign a deed restriction indicating that they will live in one of the units, and then apply for a building permit.

  • Beyond the cost of materials and construction, the homeowner faces numerous additional costs (system development charges, permitting fees, design work to ensure compliance with the various restrictions, financing charges, etc.) that significantly increase the cost of building an ADUs

Roadblocks to ADU Construction

The nearly five-pages of code restrictions on ADU’s are complicated and arcane--but in general:

  • Accessory Dwelling Units are prohibited on lots that are less than 6,100 square feet in size—even if those SDU’s simply re-purpose existing space (such as a basement, garage or upstairs bedrooms).

  • Accessory Dwelling Units are limited to 10% of the lot area, or 800 square feet, whichever is smaller. Even if a home is located on a very large lot, the homeowner cannot build an ADU that would be large enough for most small families.

  • ADUs have very specific height and roof slope restrictions. On many sites, these restrictions make it nearly impossible to build an ADU that is two stories tall, on the second floor of an existing house, or above a garage.

  • The requirement of a deed restriction to assure that the owner lives in on of the two units may be an obstacle to the owner’s selling the property in the future. This requirement thus costs the owner money and time while also reducing the property’s value.

  • There are additional hurdles for ADU’s in the Amazon, Fairmount, and South University Neighborhoods. In these neighborhoods, the minimum lot size on which ADU’s are allowed is larger (7,500 square feet), the maximum size of an ADU is smaller (600 square feet on lots under 9000 square feet), and the maximum number of bedrooms and occupants in the ADU is limited by the number of bedrooms in the main house. (For instance, the owner of a four-bedroom home could not rent an ADU to a couple with a baby).

How do we fix this?

Eugene should remove roadblocks to building ADU’s throughout the city. Among the needed changes are:

  • Remove special restrictions on ADUs in particular neighborhoods or areas of Eugene. Anyone who has a single family home should be able to build an ADU.

  • Reduce or remove lot-size requirements.

  • Remove restrictions that apply only to ADUs, but not to other buildings on a lot-- if the building is legally constructed, it should be able to be used as an ADU.

  • Review all of the code regarding ADU’s, with the goal of minimizing the obstacles to ADU construction

What would this do?

  • Allow Eugene homeowners to increase Eugene’s housing supply in a way that is compatible with existing neighborhoods

  • Help both owners and renters deal with the high cost of housing in Eugene.

Get Involved!

Want to see more ADUs in Eugene?  Get involved!