Detached ADUs (DADU) Are Now Allowed in Bellevue!!

City of Bellevue – Ordinance No. 6851 – Effective July 1, 2025

Overview

In response to Washington State’s HB 1110 (Middle Housing) and HB 1337 (Accessory Dwelling Units), the Bellevue City Council adopted Ordinance No. 6851 on June 24th, 2025. These landmark state bills required cities to open up traditional single-family neighborhoods to a broader range of housing options, and Bellevue’s ordinance enthusiastically embraces that vision.

What the Ordinance Does

The ordinance updates Bellevue’s Land Use Code to allow a variety of “middle housing” types citywide, including duplexes, triplexes, fourplexes, fiveplexes, sixplexes, townhouses, stacked flats, courtyard apartments, and cottage housing.

It also expands Accessory Dwelling Unit (ADU) rules:

• Effective July 1, 2025, ADUs are no longer required to be attached to the main home.

• Some properties can now have two detached ADUs (DADUs).

• Parking requirements are eased near frequent transit.

• Flexibility is provided for converting existing garages or other outbuildings into ADUs.

  
  

Why It Matters

• Opportunities for Homeowners: Property owners can create new income streams or multi-generational living spaces—potentially with two DADUs—without selling their property.

• Opportunities for Developers: Expanded density allowances and flexible design options mean more efficient use of land and greater potential returns on investment.

• Alleviating Housing Burdens: By making it easier to build more homes in more places, the ordinance helps address Bellevue’s housing shortage, diversify housing stock, and reduce upward pressure on prices.

• Affordable Housing Incentives: Density bonuses, relaxed dimensional standards, and other benefits are available for projects that include affordable units.

  
  

The Exciting Shift

This is more than a zoning change—it’s a transformational step toward a more inclusive and dynamic Bellevue. The city is combining state directives with local goals to create an environment where new housing types can flourish. The result: stronger neighborhoods, more housing choices, and economic opportunities for residents and builders.

Next Steps for Owners & Developers

The opportunities vary by property. Homeowners and developers should review the ordinance carefully (https://bellevue.municipal.codes/enactments/Ord6851) and consult with a professional architect to understand exactly what’s possible for their site.

Disclaimer: This is a general summary, not legal advice. Always confirm details with the City of Bellevue or a qualified professional before acting.