Table of Contents:
Key Takeaways
- ADUs are attached to the primary home while DADUs are detached, freestanding structures.
- Both can support multigenerational living, guest space, and/or rental units.
- A well-designed ADU or DADU can adapt to your needs as they change
- Washington State law (House Bill 1337) has eased permitting barriers for ADUs and DADUs statewide.
- Casali handles the entire permitting process on your behalf.
Fairhaven is one of Bellingham’s most sought-after neighborhoods. But with relatively limited lot sizes and high home prices, finding room for a growing family can be challenging. That’s part of why so many homeowners here are looking at their backyards as potential space for an ADU. These additions can add flexibility to a home that’s otherwise landlocked by Fairhaven’s tight housing market.
What’s the Difference Between an ADU and a DADU?
An ADU, or accessory dwelling unit, is any secondary living space on a property that already has a primary home. It’s fully independent from the main house with its own kitchen, bathroom, and sleeping area. There are two common types – an attached ADU, commonly referred to as an ADU, and a detached ADU, or DADU.
An attached ADU shares a wall with the primary home. For example, a converted basement or an addition with its own entrance. A detached ADU is a separate, free-standing structure on the same lot, often built as its own small backyard home or above a detached garage. Both provide valuable additional living space, with the only difference being their location.
Why Are So Many Bellingham Homeowners Interested in an ADU?
Homeowners choose to add an ADU or DADU for a variety of reasons, from creating space for family members to generating rental income. A DADU might give an adult child a way to remain in the community or provide aging parents with a way to live close by, making it easier to assist with caretaking needs while still giving them their privacy and independence. In a place like Fairhaven, where housing options are limited and buying another home nearby may not be realistic, an ADU or DADU can allow family members to live on the same property while still having their own space.
For other homeowners, the unit can provide rental income, making better use of the property they already own and adding another housing option to the community.
Does an ADU or DADU Affect Your Property’s Value?
An ADU or DADU can add value to a property by increasing its usable space and giving the lot an additional, fully functional living area. Depending on how the unit is used, it may also provide rental income or make the property more appealing to future buyers who value having a secondary living space.
The potential benefit depends on various factors, including the lot, neighborhood, design, size, and quality of the finished unit. There’s no one-size-fits-all formula for how much an ADU or DADU will increase a property’s value, but a thoughtfully designed unit can make the property more functional and potentially more marketable.
Can an ADU or DADU Adapt as Your Life Changes?
An ADU or DADU doesn’t have to serve the same purpose forever. A space built as a guest suite could later become a home for an adult child, a private living space for an aging parent, or a home office or studio. If your needs change again, the unit could eventually be used as a rental.
That flexibility is one of the biggest advantages of an accessory dwelling unit. By planning for multiple potential uses from the start, homeowners can create a space that continues to work for them as their circumstances change.
How Has Washington State Made It Easier to Build an Accessory Dwelling Unit?
In 2023, Washington passed House Bill 1337, a state law aimed at expanding housing options by easing the barriers that used to make ADUs and DADUs harder to build. The legislation pushed cities across the state, including Bellingham, to update their local rules. In most cases, this meant scaling back regulations like owner-occupancy requirements and off-street parking minimums that previously made it difficult to build.
In Bellingham today, owner-occupancy is no longer required to build or rent out an ADU or DADU, and most projects don’t need any additional off-street parking. It’s a meaningful shift from just a few years ago, and a big part of why ADUs and DADUs have become a more popular option in the Fairhaven area.
What Does the ADU Permitting Process Look Like in Bellingham?
Most ADUs and DADUs in Bellingham go through what the city calls a Type 1 permit process. Projects generally need both a land use permit and a building permit. Although this is the most streamlined review path available, it’s not always straightforward for a first-time applicant. This is exactly why Casali navigates it all on our client’s behalf – from the initial application through the final inspection. The City of Bellingham also publishes a helpful program overview, a homeowner’s handbook, and the full regulations if you’d like to read up on the details yourself.
Is an ADU or DADU right for your Fairhaven property?
If you’re weighing an ADU or DADU for your Fairhaven property, our team can walk you through what’s possible on your lot and what the permitting process will look like, or contact us directly to start the conversation.
Frequently Asked Questions About ADUs and DADUs in Bellingham
Can you rent out an ADU or DADU in Bellingham?
Yes. Bellingham homeowners can generally rent out an ADU or DADU as a separate dwelling unit, and owner-occupancy is no longer required under the city’s current regulations. Local rental, building, and occupancy requirements still apply, so it’s important to confirm that your specific project meets all applicable rules.
How much space can an ADU or DADU have in Bellingham?
The maximum size of an ADU or DADU depends on factors such as the property, zoning requirements, and the size and configuration of the primary home. Because allowable dimensions can vary by site, homeowners should evaluate their specific lot before settling on a design.
Can a small Fairhaven lot accommodate a DADU?
Possibly. A smaller lot does not automatically rule out a DADU, but available building area, setbacks, lot coverage, access, utilities, and other site-specific requirements all need to be considered. A property assessment can help determine whether a detached unit is feasible before you invest in a design.
Do you need a separate utility connection for an ADU or DADU?
Not necessarily. An ADU or DADU can often share utilities with the primary residence, although the requirements and feasibility depend on the property and the specific project. Plumbing, electrical, water, sewer, and stormwater considerations should all be evaluated during the planning process.
