UGB Expansion 101: The “One-Time” 100-Acre Rule and 2026 Affordable Housing

Oregon’s legendary land-use system is evolving to meet the modern housing crisis. Consequently, 2026 has become the year of the “one-time” expansion. Under Senate Bill 1537, qualifying cities across the state can now add up to 100 net acres of residential land to their Urban Growth Boundary (UGB) through an expedited process. This move isn’t just about growing outward; it is a surgical strike aimed at creating deed-restricted, affordable options in a market where they are desperately needed.

Key Takeaways

• Affordability Mandate: Every project built in these expansion areas must dedicate at least 30% of units to affordable housing.

• Streamlined Timelines: The “expedited” path bypasses years of traditional bureaucratic studies and legal appeals.

• Strict Eligibility: Only cities that have developed 75% of previous expansion lands can qualify for this one-time tool.

• Long-Term Protection: Rental units must remain affordable for at least 60 years under new state deed restrictions.

• Diverse Housing Types: The 100-acre rule encourages “middle housing” like townhomes, cottage clusters, and senior living.

What is the One-Time UGB Expansion?

For decades, expanding a city’s boundary in Oregon was a decade-long marathon. However, Senate Bill 1537 changed the math. The law provides a shortcut for cities to bring in up to 100 acres (or 150 acres for larger cities under recent 2026 updates) specifically for residential use. This is a “use it or lose it” opportunity. Once a city utilizes this tool, they must return to the traditional, more rigorous expansion process for any future growth.

The 30% Affordability Requirement

This expansion comes with a major string attached: the 30% rule. To use this expedited path, developers must ensure that nearly one-third of the homes are affordable. For renters, this means units are capped for those making 80% or less of the Area Median Income (AMI). For homeownership, the cap is 130% of the AMI. This ensures that the newly added land serves the workforce—our teachers, nurses, and first responders—rather than just high-end estates.

Why 2026 is the Critical Year

The clock is ticking on these land-use shortcuts. Many cities, including Bend with its Caldera Ranch selection, initiated their processes in late 2024 and 2025. Consequently, 2026 is the year we see these “conceptual plans” turn into actual construction permits. Because the state created a new Housing Accountability and Production Office (HAPO), these projects are moving through the pipeline with unprecedented speed, aiming to bridge Oregon’s 140,000-unit housing deficit.

Protecting Farm and Forest Land

One of the most debated aspects of the expansion is where the land comes from. To protect Oregon’s natural beauty, the law prioritizes “non-resource” land and urban reserves. However, new 2026 legislation (HB 4035) allows some cities surrounded by protected zones to expand slightly onto lower-quality farm or forest land if no other options exist. This “pressure valve” ensures that even geography-locked cities can participate in the affordable housing push.

The Rise of Manufactured and Senior Housing

Not all housing is built with sticks and bricks. Recent 2026 updates like HB 4082 have specifically targeted land for manufactured home parks and senior living (ages 55+). These housing types are often the most affordable “naturally occurring” options in the state. By allowing 100-acre expansions specifically for these communities, the state is helping older Oregonians find “lock-and-leave” stability without the massive price tag of traditional Westside real estate.

Infrastructure and “Complete Communities”

Adding land is only half the battle; you also need pipes and roads. Fortunately, the state has backed these expansions with a $500 million investment package. This funding helps cities build the sewer and water lines necessary to support new neighborhoods. Therefore, these expansion areas aren’t just isolated islands of housing. Instead, they are designed as “complete communities” with trails, small-scale retail, and easy access to existing city services.

Final Thoughts on Oregon’s New Frontier

The one-time 100-acre expansion is a bold experiment in urban planning. By trading a bit of land for a lot of affordability, Oregon is attempting to solve a generational crisis without sacrificing the core of its land-use values. For buyers and renters, this means more options are on the horizon. For the community, it means a more diverse and resilient place to call home.