Washington Takes Statewide Zoning Reform to the Next Level

There’s a healthy competition brewing between states that are taking action for housing abundance. But as of May 2025, Washington leads the pack. Its legislature just passed best-in-the-US bills on both parking and transit-oriented development, along with a half-dozen other policies that address the state’s housing shortage and resulting affordability crisis in several critical ways.  

These wins come on the heels of Washington’s legalization of co-living in 2024, middle housing and ADUs in 2023, and an array of bills passed in both years that make it easier to build the homes Washingtonians need.  

There’s no way to precisely quantify it, but I feel confident making the claim that Washington’s cumulative legislation adds up to the most any rival state has yet done. At least for the moment, as competitors nip at Washington’s heels! 

I gave a preview of Washington’s 2025 housing bills here. Below, I’ll run through highlights that illustrate why, together with the previous years’ wins, the bills passed this year elevate Washington to best in class. But first, a little more context… 

A quick recap of the interstate zoning reform race 

• The move from local to statewide zoning reform started in California more than a decade ago in response to local government intransigence on allowing more housing. The Golden State has had some solid wins—on accessory dwelling units (ADUs, aka “backyard cottages,” in particular)—but messy, high-stakes politics continue to mire progress. 

• Oregon leapt into the spotlight in 2019 by legalizing middle housing, followed in 2022 by  major parking reform.  

• Washington had its “year of housing” in 2023 with a suite of bills headlined by the legalization of middle housing, and then upped the ante in 2024’s “short” session. 

• Also in 2023, the Montana Miracle eliminated numerous barriers to more homes in Big Sky Country, notably for mixed-use apartments and ADUs. The state just pulled a repeat in 2025, passing strong parking reform and more. 

• Other states that have passed zoning reforms of various stripes include Colorado, Massachusetts, Arizona, and Hawaii.  

• If you include north of the border, British Columbia’s 2023 package of reforms took the crown for all of North America and indisputably held it—until now, that is, with Washington perhaps ahead by a nose! BC’s transit-oriented development policy (TOD) is stronger, but its parking reform is weaker. What’s more, it hasn’t yet legalized co-living or ended roommate bans like Washington has. 

Washington’s Housing Billapalooza 2025 

SB 5184 caps and eliminates parking mandates  

Parking policy is housing policy: laws that force the construction of too much parking thwart housing by adding cost and taking up space. Parking politics are gnarly, however, and before now, Oregon was the only state able to enact strong parking reform.  

SB 5184, or the Parking Reform and Modernization Act, works differently than Oregon’s administrative reform, but it’s comparably strong. And we can also add Montana to the list, where the legislature just passed a parking bill modeled closely after Washington’s (more on that here). 

Other states—notably California—have passed incremental reforms, typically tied to transit proximity. In contrast, SB 5184 is based on the reality that parking mandates can be detrimental to housing anywhere and everywhere. As my colleague Catie Gould explains, bill champion Senator Jessica Bateman

flipped the debate from ‘where should mandates apply’ (geographically) to ‘when should mandates apply’ (in what circumstances). It worked. Instead of nitpicking over transit service, the conversation shifted to, for example, whether it’s okay for excessive parking mandates to prevent a new daycare or senior housing development from opening. 

SB 5184 caps minimums for all multifamily buildings—that’s duplexes to skyscrapers, townhomes to small apartment buildings—at 0.5 spaces per home and fully repeals them for homes of 1,200 square feet or less. In practice, this means it ends parking mandates for nearly all apartments. Many middle housing homes and most ADUs also fall below this size threshold to enjoy full parking flexibility.  

 One last feature that makes SB 5184 exceptional: it caps mandates for commercial uses, too. That’s not directly tied to housing, but when parking flexibility unlocks attractive Main Street-style commercial areas, it also supports building more housing options nearby because plenty of people want to live there.  

As originally introduced, SB 5184 applied to all cities regardless of size, but political compromise necessitated exempting cities with populations under 30,000. Still, this means the measure applies to places that are home to about three-quarters of Washingtonians, or about six million people.  

HB 1491 legalizes more homes near transit with funded inclusionary zoning 

Transit-oriented development (TOD) is a fundamental best practice of city planning, yet statewide TOD legislation is rare. Washington has now joined the club that previously had only two members, Massachusetts and Colorado, both of which have passed strong statewide TOD legislation.   

Washington first ran its TOD bill in 2023, but that year, and when essentially the same bill ran again in 2024, it died due to disagreements over inclusionary zoning (IZ), a snag that often stymies statewide apartment-building-scale upzones near public transportation investments. Left-leaning members typically want mandated affordability, while those more toward the center rightly worry that unfunded IZ can backfire and impede homebuilding in the very places it’s needed most. 

In 2025, lawmakers achieved an unprecedented breakthrough on both the policy and politics: funded inclusionary zoning. They amended HB 1491 to grant a property tax abatement to compensate for the cost of providing the affordable units required by IZ. Multifamily developments in station areas must set aside for 50 years either 10 percent of homes affordable to 60 percent of area median income (AMI), or 20 percent at 80 percent AMI. And the value of the residential portion of the building is exempt from all property taxes for 20 years. 

HB 1491 uses the metric of floor area ratio (FAR) to set minimum densities that cities must allow near transit: FAR 3.5 (about five stories) within a half-mile of rail stations and FAR 2.5 (three to four stories) within a quarter-mile of bus-rapid-transit stops. By one estimate, this law will unlock 1.8 billion square feet of new capacity for more homes in the Puget Sound region alone (where most of the state’s transit is located anyway). The bill also completely repeals parking mandates in those station areas. 

The combination of strong upzones, parking reform, and funded IZ makes HB 1491 arguably the strongest TOD legislation yet passed by any US state. 

HB 1096 allows homeowners to split their lots 

It took three tries for Washington to pass a lot splitting bill, a measure that will both create more starter homes and give cash-strapped homeowners a financial option to age in place. In 2023 and again in 2024, the bill passed overwhelmingly in the House but then became a casualty of politics in the Senate.  

The 2025 bill, HB 1096, passed on nearly unanimous votes in both chambers. It requires cities to adopt a special lot split process that’s easier for the typical homeowner to navigate than the “unit lot subdivision” commonly used for townhouse development. The process must be administrative and is not subject to appeal. 

Designed to complement Washington’s middle housing bill (HB 1110, from 2023), HB 1096 likewise allows split-off lots as small as 1,000 square feet in cities larger than 25,000 or that are located within major metros. The bill authorizes only one lot split using the process. It also establishes guardrails to ensure that the split lot can be served by utilities and does not encroach on environmentally sensitive areas. 

SB 5148 strengthens accountability for local governments to add housing 

Passing statewide zoning reform to allow more housing is no guarantee that housing will actually get built. States also need systems for monitoring housing production, for assessing local housing plans and regulations, and for holding cities accountable if they are not allowing their fair share.  

California has had a housing accountability system in place for decades, though unfortunately it was designed in a way that has made it difficult to enforce. As directed by a 2023 bill, Oregon is developing a new, comprehensive system that will set targets, track production, and likely establish automatic upzones for non-compliance. In 2023, British Columbia enacted a system that sets housing production targets for cities, and those that fall short are required to submit planned actions to be taken within two years.  

Compared with these, Washington’s SB 5148 is relatively simple and is likely just the state’s first step toward creating more robust accountability system. The bill grants a state agency new authority to review and reject local housing plans. If a city or county fails to bring its plan into compliance, it triggers a “builder’s remedy” that requires automatic local permitting approval of any residential development, as long as it’s located where zoning allows housing and meets certain affordability requirements.  

HB 1403 reduces risk for small-scale condo development 

Throughout the United States, construction defect liability laws have hindered condo development. These laws can be especially prohibitive for small-scale condos projects, whose builders lack the deep pockets to pay exorbitant legal and insurance costs. Washington’s middle housing legalization heightened the need for reforms to better balance liability and risk, as many communities hope to see more ownership opportunities in the form of middle-housing-scale stacked-flat condos.  

HB 1403 addresses that need by authorizing an alternative to the problematic implied warranty currently mandated by state law. Developers of condos with 12 or fewer units can provide a “2-10” express warranty from a private third party, as is commonly done for detached houses.  

The bill also clarifies language in the condo liability law to reduce spurious claims, and it exempts condo-ized ADUs from envelope inspections normally required for condos. 

HB 1576 prevents landmarking from being abused to block housing 

Granting historic landmark status to buildings can play an important role in preserving buildings that represent important community heritage. Unfortunately, it can also be abused to block construction of much-needed new homes.  

In Washington, about one-fourth of larger cities, including Seattle, allow landmarking without the consent of the property owner. This enables the nomination of buildings with questionable historic value to prevent them from being demolished, precluding redevelopment into housing. 

HB 1576 is the first bill in the United States to set statewide standards for landmarking for the purpose of removing barriers to housing. It requires cities to get owner consent before landmarking any property less than 125 years old. It passed unanimously in the House and 47–2 in the Senate.  

HB 1183 knocks down barriers to innovative housing types 

Many local governments require multifamily buildings to incorporate façade modulation, which means projections in and out across the front of the building, and upper-level setbacks, which are top floor(s) recessed from the main façade.  

The problem is, these mandates make construction more expensive, reduce the capacity for housing, and for some types, can make it totally impractical to build at all. While well-intended, their aesthetic benefits are debatable at best, as it is notoriously difficult to enforce good architectural design through regulations.  

HB 1183 is the first state bill in the US to reform rules for facade modulation and upper-level setbacks. It prohibits local governments from requiring either one for passive house, mass timber, modular construction, and affordable housing. It also eliminates parking minimums for those four types. In addition, to boost energy-efficient new construction and retrofits, the bill grants extra setback and height allowances for projects that meet the rigorous passive house energy standard. 

But wait, there’s more  

• In 2023, Washington passed a bill to make it easier to add homes within existing buildings, but it had a critical flaw: it required the new housing to meet the latest energy code—which  may sound like a good idea, but in practice is usually cost-prohibitive. HB 1757 grants a reasonable allowance for added housing without triggering energy updates.  

• SB 5571 prohibits cities and counties from “requiring or excluding exterior cladding materials that are in compliance with the state building code.” The bill was motivated in part by local bans on Hardy panel for aesthetic reasons that don’t justify losing an economical option for housing construction. 

• Follow-up legislation to Washington’s 2023 middle housing bill, SB 5559, refines the process for unit subdivisions to better align with the state’s lot splitting allowances that enable townhome development.   

• SB 5471 gives counties the option to authorize middle housing within urban growth areas (Washington’s 2023 middle housing bill only applies to cities).   

• HB 1108 creates a Housing Cost Driver Task Force to study the factors driving high home construction costs and make recommendations to help bring them down. 

Three bills that died but launched conversations 

Washington’s HB 1443 was the first state-level bill in the United States to propose legalizing mobile dwellings on residential lots, modeled after legislation that Portland, Oregon, passed in 2022. MDUs are small movable homes, including tiny homes on wheels and RVs, and they can be far less expensive and far more rapidly deployed than any other type of housing. The bill passed policy and fiscal committees but never got a floor vote. It’s expected back in the 2026 session. 

Yet another first in the US, Washington’s SB 5156 aimed to legalize smaller elevators in small apartment buildings, which often don’t have elevators at all because code requires them to be so big and expensive. For accessibility, a small elevator is better than no elevator, and that’s why groups including AARP WA and Disability Rights Washington backed the bill. SB 5156 also would have required adoption of global standards for all elevators. It passed the Senate 42–6 but died in committee in the House. Expect to see it again in 2026. 

Finally, copping Oregon state law, SB 5613 would have required all development standards for residential development to be “clear and objective,” to prevent sloppy standards from enabling frivolous legal challenges that needlessly delay homebuilding. It passed the Senate 43–5, and after clearing two House committees, died when session ended before it was put to a floor vote. Its prospects are good for 2026 passage.  

Plus, a good year for protecting renters and funding affordable housing 

Sightline focuses on reforms to boost supply (the longer-game solutions to dig us out of the cost-spiking housing shortage afflicting our communities) but also recognizes the acute, near-term  urgency of the two other legs of the housing policy stool: stability, as by tenant protections, and subsidy, like in subsidized housing. In the 2025 session, Washington had wins on both.  

Most notably, after three years of trying, the legislature passed a rent stabilization bill, ending a decades-old ban on such laws. HB 1217 limits annual rent increases to 7 percent plus inflation, with a hard cap of 10 percent. It allows landlords to raise rent by any amount when a tenant vacates, and it exempts new buildings until they are over 12 years old.  

For funding, Washington’s 2025–2027 capital budget allocates a record $605 million to support subsidized affordable housing projects. The legislature also passed: 

• HB 1494 to refine the multifamily tax exemption, the state’s program that grants property tax abatements on developments that meet certain affordability requirements.  

• HB 1696 to modify 2023’s groundbreaking Covenant Home Ownership Act, the first state program in the US that supports ownership for those historically denied that opportunity.  

A race to the top for more homes  

Washington just had a very good year for legislation to create more homes of all shapes and sizes that will help undo the state’s dire housing shortage. At this point, arguably, it has accomplished more on that front than any other US state.  

But the competition is by no means over. Numerous states continue to take up zoning reforms of all sorts that could raise the bar. Connecticut lawmakers, for example, are currently working on a bill that would completely eliminate all off-street parking mandates. California has a major TOD bill in play. On the other hand, 2025 has also revealed how hard it is to pass strong statewide pro-housing bills. High-profile legislation bit the dust in both Minnesota and Maryland.  

Whatever state may have the lead, though, this is the best kind of competition. Because the real winners, in the end, are all the people who will find the homes they need in the communities they love.