What Are Urban Growth Boundaries and Why Do We Need Them?

Our goal at Greenbelt Alliance is to conserve the Bay Area’s natural and agricultural landscapes while promoting smart urban development that creates healthier, thriving communities. One of the most important policy tools that city planners can use to achieve this goal is the urban growth boundary.

What Is An Urban Growth Boundary?

An urban growth boundary (UGB) separates urban areas from the surrounding natural and agricultural lands, or greenbelts. It puts a limit on how far out the city can expand. UGBs are often set for a specified period of time, such as 20 years. Different cities may call these barriers by different names, such as “urban limit lines” or simply “growth boundaries,” but they serve the same purpose of stopping sprawl development and encouraging sustainable growth practices. Greenbelt Alliance led the fight to create the Bay Area’s first urban growth boundaries in 1996 and has been their champion ever since.

Why Do We Need Them?

Urban growth boundaries accomplish two goals:

  1. Safeguarding greenbelts from sprawl development.
  2. Encouraging smart growth which creates more mixed-use, walkable, affordable, and thriving neighborhoods within urban limits.

Compact cities and towns, rather than sprawling development, tend to be less dependent on cars, which is good for the environment as well as the community’s health. It’s easier for residents to walk, bike, or take public transportation, which reduces the city’s carbon footprint while also encouraging exercise and decreasing harmful air pollution. Additionally, a higher-density city uses less water.

Urban Growth Boundaries Are Not the Cause of the Housing Crisis

Some people may argue that urban growth boundaries make the affordable housing crisis worse. Higher-density development, however, is actually less expensive than sprawl development. For example, providing transportation and public services is much less costly in a compact city than in a spread out one. Compact development also supports the local economy by improving accessibility to local businesses. Download our urban growth boundary fact sheet to learn more (PDF).

Urban Growth Boundaries in the Bay Area

Alameda County: Alameda County, Dublin, Fremont, Hayward, Livermore, Pleasanton

Contra Costa County: Antioch, Contra Costa County, Danville, El Cerrito, Hercules, Martinez, Oakley, Orinda, Pinole, Pittsburg, Pleasant Hill, Richmond, San Pablo, San Ramon, Walnut Creek

Marin County: Marin County, Novato

Napa County: American Canyon, Napa, St. Helena, Yountville

San Mateo County: San Mateo County

Santa Clara County: Cupertino, Gilroy, Los Gatos, Milpitas, Morgan Hill, Palo Alto, San Jose

Solano County: Benicia, Fairfield, Rio Vista, Vallejo, Vacaville

Sonoma County: Cloverdale, Cotati, Healdsburg, Petaluma, Rohnert Park, Santa Rosa, Sebastopol, Sonoma, Windsor

See where we’re currently working to establish, uphold, and improve the Bay Area’s UGBs. 

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