Considering an ADU in Seattle, Bellevue, or Washington State? Here’s What You Need to Know

Accessory Dwelling Units (ADUs) are becoming increasingly popular in the Seattle and Bellevue areas, but many homeowners still wonder if they’re actually able to build one on their property. The good news is that, with the right knowledge and preparation, you can turn this dream into reality. Understanding the local requirements and regulations is key to making it happen.

Detached ADUs vs. Other Types of ADUs

When it comes to ADUs, there are several types to choose from, each catering to different needs and preferences.

Detached ADUs are standalone structures separate from your main home. These offer privacy and independence, making them ideal for renting out, housing adult children, or accommodating aging parents. In the Seattle and Bellevue areas, detached ADUs can be a great solution for increasing living space without compromising your main home's privacy.

Attached ADUs are built directly onto the existing home. While these may not provide as much privacy as detached units, they can help you maximize space efficiently by reducing the required setbacks between the main house and the ADU.

Conversion ADUs, or “junior” ADUs, involve repurposing existing spaces such as basements, attics, or spare rooms into separate living units. This option can be a cost-effective way to create an ADU if you have the right space available.

Who Can Build Detached ADUs?

In the past, building an ADU was a complicated process fraught with regulatory hurdles. However, recent changes in Washington State have made it much easier for homeowners to build detached ADUs. Local regulations are more accommodating than ever, especially in urban areas like Seattle and Bellevue, where the demand for additional housing options is high.

Washington State regulations now support the construction of detached ADUs with fewer restrictions. However, each municipality may have its own set of guidelines that can vary. For detailed, area-specific information, consulting local zoning regulations and city planning departments in Seattle, Bellevue, and other Washington cities will ensure compliance with all requirements.

Where Can You Build Detached ADUs?

While Washington State regulations have become more permissive, there are still specific rules to follow:

  • Setback Requirements: Generally, your detached ADU must be set back at least four feet from the property line. If you’re converting an existing structure, like a garage, the setback rules may be more flexible, provided the structure is legal and permitted.

  • Distance from Existing Home: The ADU must be a certain distance from your primary residence, typically ranging from six to ten feet, depending on local regulations.

How Big Can You Build a Detached ADU?

When planning your detached ADU, it's crucial to be aware of size and height restrictions:

  • Size Limits: In Washington State, detached ADUs can vary in size based on local zoning codes. Typically, they can be up to 800 square feet, but this may vary. For larger properties, some cities may allow ADUs up to 1,000 square feet or more.

  • Height Restrictions: Height limitations generally apply, with many jurisdictions allowing single-story ADUs up to 16 feet tall and possibly higher for two-story units. Check specific local regulations for precise limits.

Can You Build More Than One ADU?

Washington State generally permits homeowners to build one detached ADU along with a junior ADU. If you own a multi-family property, you may be allowed to have two detached ADUs. Consider exploring options like ADU duplexes to maximize space while managing construction costs effectively.

Should You Convert or Build From Scratch?

Deciding between converting an existing structure or building a new detached ADU involves weighing costs and benefits:

  • Conversion: If you have a garage or shed, converting it into an ADU can be more cost-effective and quicker. Ensure the existing structure is in good condition and suitable for conversion.

  • New Construction: Building from scratch offers more design flexibility but may involve higher costs. This option provides an opportunity to create a customized space tailored to your needs.

How To Design the Best Detached ADU

Designing and constructing a detached ADU requires careful planning. Partnering with a specialized ADU company familiar with Seattle and Bellevue regulations can simplify the process. They can guide you through design, permitting, and construction, ensuring that your ADU meets all local codes and your personal needs.

Choosing the Right ADU Designer and Builder

Selecting the right ADU company is crucial for a successful project. Look for a firm with experience in the Seattle and Bellevue areas and a proven track record. Cottage is a reputable custom ADU company that offers comprehensive services from design to construction, ensuring a smooth and hassle-free experience.

Ready to transform your property with an ADU? Contact GENPRO and explore your options and get expert advice tailored to the Seattle, Bellevue, and Washington State areas.

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