Maximizing Your Home's Value: What Washington's New Housing Laws (HB 1337, 1110, & 5258) Mean for You.

• Maximum Unit Count : You may now create up to two ADUs per property, in addition to the single-family dwelling if your lot is greater than 20,000 sqft.

• Income & Investment Potential : You can apply for a Unit Lot Subdivision to sell an ADU as a separate unit or condo . This allows you to generate revenue by selling off a portion of your lot to a new owner.

• New Size Limit : Each ADU may not exceed 1,000 square feet of gross floor area, which includes habitable interior space like basements and attics, but excludes garages or storage sheds.

• Parking Requirement : ADUs must provide off-street parking, with minimums of 2 spaces per unit on lots over 6,000 square feet, and 1 space per unit on lots under 6,000 square feet (unless near a major transit stop).
• Separate Identity : Each approved ADU must have a separate numbered address established by the City and must be registered with King County.

• Unlock Hidden Equity: Many homes in our neighborhood can now add a second unit. Find out if your lot qualifies.

What It Is: The Clyde Hill Implementation

HB 1110 is the state law requiring cities to allow "middle housing" (buildings with two or more attached, stacked, or clustered homes) in areas formerly zoned exclusively for detached single-family homes.  The City of Clyde Hill's adopted ordinance does not allow attached duplexes or townhomes; instead, it meets the minimum state mandate by allowing two specific types of units on residential lots:

• Two Cottage Housing Units OR
• One Single-Family Home + up to Two ADUs

• Mandated Density: Allows a minimum of two residential units per lot (single-family homes are still allowed).

• Increased Development Scale: The City limits middle housing to two units total (two cottage homes, or one house + two ADUs).

• Parking Requirements: Cottage Housing units require 2 spaces per unit on lots larger than 6,000 sq ft, and 1 space per unit on lots smaller than 6,000 sq ft.  

• Future Density Alert: The rules are now final: Every residential lot in Clyde Hill can now host at least two cottage homes or a house and up to two ADUs. Find out if your property is large enough to qualify for these new options, or if your HOA rules restrict you from building the new housing types.

What It Is: Clyde Hill's Unit Lot Subdivision (ULS)

Unit Lot Subdivision allows a single property (the parent lot) to be divided into smaller lots, each with its own individual owner, enabling the separate sale of individual units—similar to condominiums . This process can be used to sell ADUs or Cottage Housing units separately.

• Eligibility Restrictions: To be eligible for a Unit Lot Subdivision, the original parent lot must meet the minimum required lot area of 20,000 square feet 

• Shared Area Liability: Portions of the parent lot not included within the individual unit lots must be owned in common by the unit lot owners or by a Homeowner Association (HOA) 

• Flexibility on Zoning: All development within the ULS must still comply with the design and development standards of the original parent lot (setbacks, lot coverage, etc.).

• Utilities Requirement: Each unit lot must be served by its own separate utility meter at the time the subdivision is established .

• Understand Your Property Lines: New fee-simple ADUs and Cottages can now be created and sold next door. If you own a qualifying lot, understand the complexity of the ULS process—it requires recorded agreements for easements, joint use, and maintenance that bind all future owners of the unit lots.

• Disclaimer: For specific requirements, see Chapter 16.12.100 of the Clyde Hill Municipal Code.