To ADU or Not to ADU?

Accessory dwelling units (or ADUs for short) are a hot topic in Whatcom County and throughout Washington State. As the trend of tiny houses, she-sheds, man caves, crafting cottages, and separate home offices has taken off, there are more and more home owners utilizing small separate buildings to add to their living space.

An ADU is an extra unit located on the same property as a single-family home. Examples of ADUs iinclude: mother-in-law suites, backyard cottages, garden suites, granny flats and garage apartments. ADUs are often used by homeowners as a source of extra rental income.

The zone in which you live dictates whether you can have an ADU and what kind of ADU is allowed on your property. Your local permit office should be able to how your property is zoned.  Unfortunately, you cannot determine your zoning based on how you see your neighbors using their property.

In several of Whatcom County’s residential zones, ADUs are only allowed with the approval of the County after the property owner has submitted an application.  Bellingham’s single-family residential zone limits ADUs to 800 square feet, and 40% or 50% of the size of the main residence depending on the circumstances. In Lynden and Bellingham single family residential zones, ADUs must be attached to the main home, no detached ADUs are allowed.

In Whatcom County, the owner of the property must live in either the primary residence or the ADU. Bellingham and Ferndale require owners to submit an affidavit every other year confirming that one of units on the property is owner-occupied.

If you are living in a home-owners association, you may face additional restrictions on your ability to build or rent an ADU on your property. Your permit office might not be able to tell you if you are subject to association restrictions, you will need to fully review and understand your CC&Rs before determining if your HOA allows them (or have an attorney do that for you).

This post provides a brief overview of some of the kinds of ADU regulations you might see in Whatcom County. If you have additional questions or concerns the permit office is unable to address, feel free to call Limitless Law PLLC at 360-685-0145 for a free 15-minute phone consultation.