Washington state legislators in the House and Senate are sponsoring a bill (HB 1797 / SB 5812), giving homeowners more freedom and flexibility across the state to add Accessory Dwelling Units (ADUs)—backyard cottages, granny flats, basement apartments, and mother-in-law suites.
In cities of 2,500 people or more, and within urban growth areas, the bill would permit:
- Two ADUs wherever there is a single, detached house, duplex, triplex, or townhome;
- Eliminate off-street parking, owner-occupancy, and minimum lot size requirements;
- Cap impact fees at 50 percent of rates for single-family homes;
- Set utility connection fees and capacity charges in proportion to ADU’s burden; and
- Increase design flexibility via more generous setback, height, and size limits.
This kind of ADU solution delivers flexibility, affordability, sustainability, expanded economic opportunity and housing stability to households across the state.
How ADUs benefit our communities:
Affordability: Modest, convenient homes
High rent and home prices are driving people out of Washington communities. Adding modest, affordable homes to existing neighborhoods is an important tool to protect communities where all kinds of families, of all incomes, can afford to live.
Shared opportunity and foundations for equity
Where we live shapes our lives and our long-term success—from the length and cost of our commute, where we shop for groceries, and our children’s schools. Modestly priced housing options can provide more equitable access to jobs, schools, transit, and parks.
Flexibility for all stages of life
Backyard or basement apartments give homeowners more flexibility to age in community, care for family members, earn income from a small rental, or support a young adult just starting out.
Economic and housing stability
Workforce housing near places people work builds economic security and housing stability for middle- and low-income families and access to jobs and amenities helps families and businesses thrive.
Sustainability: A solution for pollution, sprawl, traffic, long commutes, and climate damage
Small apartments that are convenient for transit, jobs, schools, and amenities are an important tool in the fight against climate change. Adding housing choices in existing neighborhoods near these amenities prevents sprawl, cuts traffic and commute times, and tames infrastructure needs. ADUs are also compact, making them remarkably energy efficient, cutting lifetime CO2 emissions by as much as 40 percent compared with a typical detached home.
Washington be a model for greener, more affordable communities
This is the most progressive accessory dwelling unit proposal legislators from any state have ever had the opportunity to vote on. Washington legislators can take leadership to give all jurisdictions the chance to pitch in and do their part to create more green and affordable housing options that work for families across the state.
Download a PDF of our ADU policy explainer and tips for communicating the multiple community benefits of ADUs: