Updated April 18, 2025
What is middle housing?
“Middle housing” or “middle-scale housing” is a term used to refer to residential developments that are more dense than single-family housing and less dense than a typical midrise apartment building, but similar in scale to single-family homes. Middle housing types are determined by the form of the structure and the number of units within the structure and/or development.
Densities included in this definition that describe units per structure include:
- Duplexes
- Triplexes
- Fourplexes
- Sixplexes
Building structure types included in this definition are:
- Townhomes
- Stacked flats
- Cottages
- Courtyard/garden style apartments
Why are we updating the city's codes for middle housing?
In 2023 the Washington State Legislature passed House Bill (HB) 1110, which requires many cities in the state to update their codes to permit middle housing in all residential areas. These changes are required to increase the variety of housing options and overall housing capacity in Bellevue and throughout the state.
Is the city proposing to go beyond the minimum requirements of HB 1110?
Yes. The city is proposing a few components that go beyond the minimum requirements of HB 1110, which include:
- Permit all of the nine types of middle housing, subject to any applicable development regulations.
- Allowing up to six units by-right in certain key areas of the City such as within one-quarter mile walking distance of frequent transit service, and within one-quarter mile walking distance of mixed-use and neighborhood centers. HB 1110 requires that we allow up to six units when two are affordable citywide.
- Exempting Accessory Dwelling Units from the max allowable density and maximum square footage allowed on a lot, which is encouraged by the state’s guidance.
- Allowing for some flexibilities in development standards such as setbacks and lot coverage, which is also encouraged by the state’s guidance.
- Adopt a parking standard of one space per unit for all middle housing rather than for only smaller lots
- Tree retention flexibilities for cottage style developments
Does middle housing include Accessory Dwelling Units and will the city allow them?
The state also approved HB 1337 in 2023, which requires that jurisdictions adopt regulations permitting up to two Accessory Dwelling Units (ADUs) per lot, which can be any combination of an attached and/or detached ADU. The code does not currently allow detached ADUs. However, the Comprehensive Plan was recently amended to permit them. We are updating the zoning regulations to align with the new Comprehensive Plan policies related to ADUs and the HB 1337 requirements. Attached ADUs, such as an ADU in a converted basement space, are currently allowed. Additionally, we are considering an approach for the middle housing code that would allow ADUs in addition to middle housing rather than only an accessory to a single family home. After adoption of the middle housing code update, the city plans to develop a pre-approved ADU design program to help residents construct ADUs on their lots.
When will the new regulations go to into effect?
The city is required to adopt regulations consistent with HB 1110 and 1337 by June 30, 2025.
What does this mean for my lot?
If you own a home in a single-family land use district (R-1 through R-7.5), once the regulations are in effect you may be able to have multiple units on your lot. This could include the addition of one or two ADUs with your primary home, or any other combination of units and structure types that works with the space you have and your needs. If you prefer to keep your property as-is that is also allowed under the new regulations. There is nothing in the bill or the anticipated code changes that would require someone to change their property.
What if my lot has covenants?
The city does not enforce private covenants or Homeowners Association (HOA) requirements. Covenants are private legal agreements—typically recorded in county real property records—that impose restrictions on land use. Many covenants prohibit the construction of any type of dwelling unit besides a single-family dwelling, which is the primary topic of discussion we have heard regarding covenants and middle housing. These covenants are contracts, and both the Washington State Constitution and the United States Constitution limit the extent to which government can interfere with previously executed contracts.
Residents whose homes are subject to HOA requirements should review and understand what HOA rules apply to their property that may restrict some of the development regulations that apply to their lot.
What does "walking distance" mean?
Walking distance is the term used when looking at whether or not a property may qualify for additional middle housing units adjacent to certain geographies, or parking exemptions near transit. Applicants will need to provide visual evidence that it is feasible to walk from a given property to the transit stop or other geography that provides the allowance for extra units or parking exemption.
Is middle housing affordable?
Middle housing is generally less expensive than single-family homes, but often doesn’t meet the affordability criteria used by many jurisdictions. Affordable housing is typically defined as non-market rate units affordable to individuals earning 80% or less of the area median income. However, encouraging middle housing adds valuable housing diversity, providing options for those who cannot afford single-family homes and prefer alternatives to a typical apartment.
Can middle housing be rented or purchased?
Whether or not a middle housing type of development will be available to rent, or purchase is up to the owner of the property. The city does not regulate whether housing is for sale or for rent regardless of the type of housing.
What is a unit lot subdivision and how do they differ from standard subdivisions?
Unit lot subdivisions is a land division process to create fee simple lots for multifamily projects like townhomes and other middle housing types. The intent is to allow each unit within a development to be placed on its own lot, even though the project was originally developed as a single site.
Under HB 1110, cities must allow any of the middle housing types to use unit lot subdivisions. For example, a cottage housing project could be subdivided so that each cottage sits on its own lot. Unlike standard subdivision processes, unit lot subdivisions do not have a required minimum lot size—instead, the design of the housing project drives the lot layout.
Importantly, unit lot subdivisions differ from standards subdivisions because the resulting lots are categorized as “unit lots,” and the original lot is categorized as a “parent lot,” meaning they are intrinsically tied to each other. This means “unit lots” are not independent buildable sites. Additional development beyond the project proposed through the original unit lot subdivision may be restricted. Within the context of middle housing, this ensures the unit lot subdivision process cannot be used to circumvent minimum lot size standards to create new lots that could then be redeveloped at higher middle housing densities.
How will middle housing impact critical areas and trees?
All development in the city must comply with critical areas and tree code requirements. The city recently updated its tree code requirements in anticipation of middle housing code changes. To ensure these recent code changes are effective, staff plan to evaluate the tree code and make adjustments to support middle housing and minimize impacts of tree code and landscaping requirements.
What are the proposed requirements for detached accessory dwelling units (DADUs)?
DADUs would be subject to the following:
- Maximum size of 1,200 square feet
- Additional 250 square feet for a garage or unheated storage space
- Maximum height of 24 feet, or 28 feet when built above an existing detached structure
What are the proposed requirements for cottage housing?
Cottages would be subject to the following:
- Maximum size of 1,750 square feet
- Additional 250 square feet for a garage or unheated storage space
- Maximum height of 38 feet, which restricts residential structures to three stories
- Lot coverage increase where covered porches are provided up to 25%
- Open space is required at 20% of the site in total, with some of that space dedicated common open space. Common open space is required at 100 square feet per cottage. Smaller cottage developments may utilize driveway access for common open space
- Minimum landscaping and maximum hard surface requirements for open space
What are the proposed requirements for courtyard apartments?
Courtyard buildings would be subject to the following:
- Building shall be in an L- or U-shaped configuration
- There shall be a central courtyard area accessible by all units
- Minimum landscaping and maximum hard surface requirements for courtyard
What is the impact on infrastructure?
Any time a new development application is received by the city, an applicant must show that either the existing infrastructure can support the proposal or show how they are improving infrastructure in order to be able to support the proposal. These improvements made at the time of development can include upgrades to water and sewer mains, frontage improvements that include sidewalks and street trees, undergrounding of any existing overhead utilities like powerlines, and others. While the city does work to upgrade utilities over time, the timing and projects for city funded infrastructure improvements are developed through the utilities planning team. However, this process takes time and occurs in the areas that have been planned for in specific planning windows.
Infrastructure improvements are often very costly, meaning it is likely that many smaller infill projects may not be feasible if extensive infrastructure requirements would be needed in order for the project to be built. These required infrastructure improvements are one of the very likely feasibility limitations on middle housing development that will be seen in the city.
What public engagement has the city done to-date on middle housing?
City staff, along with partner organizations on the Eastside, have conducted extensive engagement on middle housing as part of the broader Comprehensive Plan Periodic Update process. Key engagement work is summarized in publicly available documents, including a middle housing questionnaire from November 2022, a June 2023 engagement report compiled by Eastside Housing for All in collaboration with partner cities and A Regional Coalition for Housing (ARCH), and a statistically valid survey conducted as a part of the June 2023 engagement report. These materials are all available on the Middle Housing Code Amendments project webpage.
How can I provide input on middle housing code updates in Bellevue?
Public input is always welcome. Comments may be submitted directly to Kirsten Mandt, Senior Planner, by email or by phone. Comments can also be shared with the Planning Commission. For the latest schedule of engagement events and Planning Commission meeting dates, please visit our Middle Housing project webpage.
Staff is preparing additional engagement activities related to the more technical aspects of middle housing code, which will be available in December on the project webpage.