ADU requirements

Seattle ADU Requirements

Just like any other type of construction project, having clear floor plans is a vital part of ADU construction. The good news is that we have experienced and talented contractors to work on your Seattle and King County ADU plans. 

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Site visits are required to spec the feasibility, cost, and design of your ADU project. We have to survey, architects drawings and submit to the city for permits approval. Then we can build!

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To utilize your background space properly, you should first have ideas about the requirements. Many Seattle ADU builders are here to guide you through all the requirements. But we, Emerald ADU Builders, work with our clients as if it is our problem.


Besides, you need to have proper ideas about them. In this way, we gain their trust. Without delaying more, let's tell you about the requirements for the ADU backyard:


Seattle ADU Requirements


First, having some basic ideas related to ADU or Accessory Dwelling Unit is essential to understanding the requirements. They are:


ADU Or Accessory Dwelling Unit


An ADU is the extra residential unit with your main building in the backyard of your house. You can build them by attaching them to your main building or detaching them entirely. 


SFD Or Single-Family Dwelling


You can call an SFD a duplex also. Besides, two units will be in the same building as for SFD. In addition, there will be no ADU and JADU here. 

     

JADU Or Junior Accessory Dwelling Unit 


An ADU Seattle with a space of 500 sq feet maximum is called a JADU. A JADU is built, transforming an SFD or a single-family dwelling. 


MFD Or Multi-family Dwelling


For an MFD, there will be three or more three dwelling units in the same building. No ADU and JADU will be there. 

 

Now we will go for the requirements:


  • Limit Of ADU


You can build three ADUs in every residential area. One of them will be JADU, and the other will be detached, a residence for a single-family. 


  • Rental Terms


You can rent them. But the rental period will be 30 days and more than that. Renting them for the vacations probably will not have permission. 


  • Owner Occupancy


Till the year 2025, the cities do not need the owner occupancy. Whenever you have both the ADU and JADU, JADU requires the owner-occupancy according to the law. 


  • A Certificate of Appropriateness 


To build your ADU, you need to have a COA or a Certificate of Appropriateness. Thus, the construction and permission are given for building your ADU to you from the department related to it. 


  • City Approval and Hearing


When you ask for permission to build your ADU, the authority will review it. It will do within two months of your submission. The timeline of two months will start when the city act is done on your SFD/MFD. Only when there is no SFD or MFD in your area. 


  • Individual Entrance


Individual entrance is an essential requirement. You must have one for your ADU.


  • Bedrooms


There is no limitation on the number of bedrooms in your ADU. It is an obstacle to building up your ADU. 


  • Kitchens


To provide all the facilities, an ADU will need to have space for living correctly with all the facilities like sleeping, cooking, etc. May It be for a single or multi-family dwelling. The same is for the JADU too. You will have to share a kitchen or provide there one. 

 

  • Washroom


Every ADU should have a washroom with a shower and sink. It is also called a 3/4 bath. In the case of the JADU, you may keep an individual restroom or share them too. 


  • Fire Sprinklers


Safety facilities cannot be averted for your ADU too. To ensure the protection of the inhabitants, you will have to give them fire sprinklers. A smoke alarm will add another benefit to it. 


  • Minimum Size


The size of the ADU also requires its build-up. The minimum size of it will be 150 sq ft.


  • Construction Rules For ADU


Whatever country or city, an ADU less than 1200 sq ft is allowed everywhere. It may vary according to the plan of the town. Two rules you have to abide by here. Firstly, the limit of a unit will be more than 1000 sq ft or less than 800 sq ft. Secondly, the floor area will be a minimum of 800 sq ft. 


  • Garage Conversions 


You can go for your garage conversion along with barns or sheds. You may build them up by attaching them to your ADU or detaching them from it. 


  • Height Limit for One Storey and Line Setbacks


The maximum height of a single ADU is 16 feet. The rear and side setbacks will be 4 feet. 


  • Height Limit for Two Story and Line Setbacks


The local ordinance will give you an idea about your two-story ADU. The line setback will be determined by them too. 


  • Lot Size Requirements


For a legal lot, the size has not been given any limit. You will have to follow the requirements for the local zones.


  • Fees


You have to pay the development and impact fees of an ADU. But fees for an ADU with 750 sq ft and less than that are not accepted by the law. Only those who are 750 sq and larger have to pay a certain amount as fees. 


  • Permissions Of the HOA (Homeowners Associations)


You must take permission from HOA or Homeowners Associations to start your construction. Otherwise, you can’t start the construction. 


  • Utility Fee 


When you already have a visible structure of an ADU, you don’t have to pay fees for the capacity and connection. For the separate ADU structures, you will have to pay them. 


  • Solar Panel Requirements


You have to provide solar panels for the new and detached ADU. But not for all of them. Which are constructed in the existing space as an additional home, there is no need for solar panels. 


  • Parking


You should arrange for a parking zone for ADUs with specific requirements. Not for each ADU. 


  • Mixed-use Zoned and MFD Properties 


You can build up to two new attached or detached ADU. The non-livable area will add a total dwelling unit of 25 percent. The height will be 16 feet, and the rear and side setbacks will be 4 feet. 


  • Selling Your ADU


You cannot sell your ADU alone from your main building. 


  • Zoning Districts


There are requirements for permissions for both the SFD and MFD. After getting that, you can build your ADUs or JADUs in the zoning districts as a residence. Residential utilization is also allowed in the planned development and mixed-use zoning districts with a different plan. 


Conclusion

As one of the best Seattle ADU Builders, we will let you know all the requirements for building your ADU. So that you can live peacefully in your home, the motto of Emerald ADU Builders is that. Our years of successful experience will not let you down when you trust us for building your ADU!


Call (206) 222-2898 for immediate assistance.

How ADU Construction Process Works

  • 1. Send a request

    First things first - send a request to us to start the process. 

  • 2. Site Walk-through

    We will do a walk-through of your property to scope out the project and look for any issues. 

  • 3. Design & Planning

    Choose a building design and plan to the specifications of your property. 

  • 4. Permitting

    Permits in the city of Seattle are mandatory and we help you along with the process. 

  • 5. Build

    Once everything is approved we will start the building process.

  • 6. Completion

    After the build, we always do quality control and inspection for project completion.

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