Why do buildable lots feel scarce in Tigard and across Portland’s Westside? If you have been watching inventory or pricing, you have likely felt the squeeze. The region’s Urban Growth Boundary is a big part of the story. In this guide, you will learn what the boundary is, how it shifts where and what gets built, and what that means for your next move. Let’s dive in.
What the Urban Growth Boundary Is
Why Oregon uses a UGB
Oregon uses a regional Urban Growth Boundary (UGB) to direct urban development to specific areas while keeping other land in rural or agricultural use. The intent is to curb sprawl, protect farms and natural resources, and target infrastructure investment where it serves the most people. Inside the boundary, land is eligible for urban services and higher-density zoning. Outside, rural uses are protected.
Who manages Portland’s UGB
The Portland area’s UGB is managed by Metro, the regional government. Oregon’s statewide land use system, created in the 1970s, provides the rules and oversight through the state’s land conservation department. Cities and counties, including Washington County and the City of Tigard, apply local plans and zoning within the boundary to shape what can be built on each parcel.
How changes happen
UGB expansions are possible, but they are formal, infrequent, and based on need. Metro reviews population and jobs forecasts, buildable land inventories, and infrastructure capacity before considering any expansion. Local governments must also show how they will add housing inside the boundary through rezoning, infill, and redevelopment before asking for more land.
How the UGB Shapes Lot Supply
Finite greenfields inside the boundary
By setting a firm edge for urban services, the UGB limits long-run greenfield land supply. Over time, fewer large tracts remain for traditional single-family subdivisions. This scarcity pushes development toward smaller lots, infill parcels, and attached homes.
Infill, redevelopment, and ADUs
When large tracts are scarce, builders shift to lot splits, small-lot single-family projects, townhomes, and apartments. You also see more accessory dwelling units (ADUs) added in existing neighborhoods. Underused commercial sites may transition to mixed-use housing where local plans allow it.
Infrastructure sets the pace
Even inside the UGB, timing depends on sewer, water, and roads. Parcels without nearby infrastructure are slower and more costly to bring online. Builders often prioritize sites with existing capacity because that improves feasibility.
Westside Patterns: Tigard, Beaverton, Hillsboro
Tigard: infill near transit corridors
Tigard is more built out in many neighborhoods, so most new housing comes from infill, lot splits, and corridor-area redevelopment. Areas near transit and main streets draw more attached housing and mixed-use projects where zoning allows. Small-lot single-family options appear in pockets where infrastructure supports them.
Beaverton and Hillsboro: evolving mix
Beaverton and Hillsboro historically had more greenfield options, but those have tightened over the years. New supply has shifted toward higher-density homes, townhomes, and apartments, often near jobs and services. Large single-family subdivisions are less common and more expensive to deliver.
Zoning and transit guide where density goes
Zoning, neighborhood plans, and transit access shape project types across the Westside. Corridors served by MAX or WES, or set for future upgrades, tend to see more multi-family and mixed-use development. This pattern helps add units without expanding the boundary.
What It Means for Prices and Value
Scarcity lifts land values
Limiting where urban development can occur increases competition for sites inside the UGB. That scarcity puts upward pressure on land prices, which influences the cost of new homes. The effect is strongest for large parcels suited to single-family subdivisions.
Densification helps but changes the mix
Allowing more units per acre can produce more homes without expanding the boundary. That can help moderate per-unit prices. Still, apartments and townhomes are not perfect substitutes for detached homes with yards, so single-family homes may command a premium.
Local factors that move the needle
- Employment hubs on the Westside increase demand close to work.
- Access to major corridors and frequent transit boosts land values.
- Infrastructure costs and timing affect how fast lots can be created.
- Zoning that enables ADUs, duplexes, and small-lot single-family adds capacity without boundary changes.
Practical Moves for Buyers and Sellers
For buyers: reading the market
- Expect fewer large new subdivisions and more small-lot or attached options.
- Consider townhomes and ADU-ready lots if a detached home is out of reach in your target area.
- Watch where infrastructure and transit investments are headed, as those areas often add new choices.
For sellers: positioning for today
- Highlight features that are scarce under the UGB, such as larger yards or flexible spaces for multigenerational living.
- If your property allows an ADU or has potential for a lot split, document that zoning path to expand your buyer pool.
- Prepare for appraisal and buyer questions about nearby development and access to services.
Indicators you can monitor
- Buildable land and housing capacity reports from regional and local planners.
- Building permits by type to see whether single-family or multi-family is growing.
- New-lot listings and small subdivision announcements to gauge pipeline supply.
- Zoning map updates and corridor plans in Tigard, Beaverton, and Hillsboro.
- Infrastructure and transit project timelines that can unlock development.
Policy Levers to Watch
Local zoning and code updates
Cities can adjust minimum lot sizes, allow narrow-lot homes, and streamline ADUs to add capacity. Incentives and faster permitting can encourage infill and transit-oriented projects. These choices influence what gets built in the near term.
Metro UGB cycles and housing analyses
Metro periodically reviews housing needs and land supply to decide if UGB adjustments are warranted. Expansion requests are rare and require proof that internal capacity and infrastructure will not meet projected needs. Tracking these cycles helps you anticipate where new supply might emerge.
Transit and infrastructure projects
Sewer, water, and road improvements often determine which parcels come online next. Corridor upgrades and transit investments can both increase demand and enable higher-density housing that relieves pressure elsewhere.
The bottom line
The Urban Growth Boundary shapes housing across Tigard and the Westside by limiting outward expansion and steering growth to infill, redevelopment, and higher-density options. That structure can support long-term value, especially for single-family homes on scarce lots, while also encouraging a broader mix of housing types. If you are planning a move, read local zoning updates, follow infrastructure projects, and align your strategy with where supply is likely to arrive next.
Ready to navigate Westside inventory with a local advisor who understands how the UGB affects value street by street? Connect with Tracy Brophy to Request a Market Consultation or Free Home Valuation.
FAQs
What is Portland’s Urban Growth Boundary and who manages it?
- The UGB is a regional line that directs urban development and protects rural land, managed by Metro under Oregon’s statewide land use system, with cities and counties applying local zoning inside it.
How does the UGB affect single-family lot supply in Tigard?
- It limits large greenfield subdivisions over time, so new lots tend to come from infill, lot splits, and small projects rather than big tracts.
Does the UGB make homes more expensive on the Westside?
- It increases competition for developable land, which can push prices up, though added density and different housing types can moderate per-unit costs.
Can the UGB expand near Tigard, and how often does it happen?
- Expansions are possible but infrequent and require Metro to find that internal capacity and infrastructure cannot meet projected needs.
Where is new construction happening in Tigard, Beaverton, and Hillsboro?
- You will see more infill, townhomes, and apartments near transit and corridors, with fewer large new single-family subdivisions than in the past.
What should Tigard sellers watch if they plan to list?
- Monitor local zoning updates, nearby infrastructure plans, and new project announcements, and showcase any ADU or lot-split potential to widen your buyer pool.
