Housing production in Boulder, CO, USA

While on vacation in Boulder, Colorado, I recalled that in 1976, Boulder adopted residential growth limits known as the Danish Plan (based on the last name of its author), capping the number of new dwelling units annually to control the growth rate. This measure, modeled after an ordinance in Petaluma, California, was one of the first and most widely emulated early community growth management plans in the country.

I used artificial intelligence (AI) as a research and writing tool to explore and document how Boulder’s half-century experience with growth management has affected housing production. Other than light editing by me, this post was prepared by Copilot, an AI bot developed by Microsoft (in collaboration with OpenAI).

Boulder’s housing production history is a fascinating blend of growth management, affordability efforts, and citizen activism and resistance. Here’s an overview of key milestones and trends.

Early Growth & Citizen Pushback (1950s–1970s)

• 1950–1970: Boulder’s population tripled, sparking concerns about overdevelopment.

• 1959 Blue Line: Voters approved a municipal charter limit on extending water service above 5,750 ft elevation to curb hillside development.

• 1967 Open Space Tax: First voter-approved sales tax for open space, creating a greenbelt to contain sprawl.

• 1970 Growth Initiative: A failed ballot measure aimed to cap population at 100,000, but it led to significant shifts in city council and scaled-back growth projections.

Formal Growth Management & Affordable Housing (1970s–1990s)

• 1976 Residential Growth Management System (RGMS): Capped residential building permits at 2% annual growth, with incentives for affordable housing.

• 1982 ADU Ordinance: Allowed accessory dwelling units in low-density zones to diversify housing options.

• 1985 Moderate Income Housing Program (MIHP): Required 15% of units in new developments to be sold to moderate-income households, with resale restrictions.

Inclusionary Zoning & Affordability Challenges (2000s–Present)

• Ongoing Zoning Constraints: Strict land use regulations have limited housing supply, contributing to rising costs.

• Shift Toward Exclusivity: Once-affordable neighborhoods like Martin Acres and Newlands have become less accessible to service workers and middle-income families.

• Recent Proposals: City leaders are considering reserving a percentage of units for essential workers to maintain community diversity.

Boulder’s housing story is one of balancing environmental preservation, community character, and affordability—often with tension between these goals. In recent years, Boulder has taken steps to allow more apartments and mixed-use development, though always within the city’s carefully managed growth framework.

Recent Mixed-Use & Apartment Projects

Diagonal Plaza Redevelopment

This long-blighted site is being transformed into a vibrant mixed-use area. It includes:

• 207 market-rate units across four buildings

• 73 affordable apartments developed by Boulder Housing Partners, with rents targeted for households earning 30–60% of AMI

• Shared amenities like a community park, solar arrays, and transit access.

S’PARK District

A major redevelopment of a former lumberyard into a 434,000 sq ft mixed-use community:

• Includes 142 apartments, 38 affordable units, and 8 townhomes

• Features coworking spaces, retail, courtyards, and a woonerf-style plaza

• Designed to promote walkability and transit connectivity C

Broader Policy Shifts

• Boulder has been incrementally updating zoning to support higher-density infill, especially near transit corridors like 28th and 30th Streets

• Inclusionary housing requirements have led developers to partner with affordable housing providers or dedicate land for subsidized units

• The city is also exploring form-based codes and overlay districts to encourage mixed-use nodes while preserving neighborhood character.

So, while Boulder’s growth management legacy still shapes development patterns, there’s a clear pivot toward more integrated, higher-density housing—especially in underutilized commercial zones. Want to see how these projects fit into the city’s broader land use map or compare them to earlier phases of development?

Boulder housing production metrics over the decades since 1970

1970s

This decade saw Boulder’s shift from post-war sprawl into more consciously managed growth. The 1976 passage of the Residential Growth Management System (RGMS) capped annual housing approvals, which started reducing unit counts toward the end of the decade.

1980s

The RGMS’s regulatory friction became more pronounced here, with annual quotas constraining not only volume but typology diversity. Multifamily proposals faced greater scrutiny, leading to a lopsided supply and rising price burdens.

 1990s 

This decade marked Boulder’s hesitant pivot toward diversification. There was increased pressure to address affordability, especially as regional commuters grew and job centers expanded along US 36. Yet RGMS remained intact, meaning growth was shaped more by negotiation than momentum.

 2000s

Boulder’s growth this decade was more focused on infill than expansion—recycling land via mixed-use planning, downtown upzoning, and transit-oriented development. Yet neighborhood resistance kept the housing mix relatively static. Multifamily growth edged forward, but not enough to meaningfully alter affordability trajectories.

2010s

During this decade, Boulder began grappling in earnest with the regional housing crisis. While RGMS remained formally active, the council introduced strategic density incentives, streamlined accessory dwelling unit (ADU) approvals, and explored “gentle density” solutions. Yet opposition to scale and intensity continued to shape what was feasible.

 2020s (as of mid-decade)

 Boulder’s been negotiating a complicated balance between its compact urban footprint, progressive climate goals, and rising regional housing pressures. Inclusionary zoning has expanded, there's been movement toward middle housing overlays, and the city’s Comprehensive Plan updates have pushed for transit-aligned growth—but political consensus remains elusive.

 The housing affordability ratio in Boulder is among the highest of comparable college towns in the West. It reflects Boulder’s constrained land supply, strong demand, and planning limits on dense growth. Compared to cities like Eugene and Fort Collins, Boulder’s affordability has worsened in recent years.

 Boulder compared to other university towns

Boulder’s housing trajectory shares some DNA with other progressive, university-adjacent towns—but it also stands out for how early and aggressively it embraced growth management.

 Here are a few comparisons:

Fort Collins, CO

·       Growth Controls: Boulder introduced its Residential Growth Management System in 1976 to limit yearly housing expansion. Fort Collins later adopted comparable measures but with greater flexibility.

·       Affordability: Both cities face affordability challenges, but Boulder’s median home prices are significantly higher, hovering around $935K in 2025.

·       Zoning & Density: Boulder has historically resisted upzoning, while Fort Collins has been more open to mixed-use and higher-density infill.

Eugene, OR

·       University Influence: Both are shaped by large universities (CU Boulder and the University of Oregon), but Eugene has allowed more student-oriented housing near campus.

·       Preservation vs. Expansion: Boulder’s open space program created a hard edge to growth, while Eugene has expanded more freely into surrounding areas.

Berkeley, CA

• Activism & Policy: Both cities have strong citizen engagement and progressive values, but Berkeley has pushed harder on tenant protections and rent control.

• Housing Stock: Berkeley’s older housing stock and denser urban form contrast with Boulder’s suburban-style neighborhoods and strict height limits.

 Housing Data Comparison (2025 Estimates)

Here’s a comparative snapshot of key housing metrics for Boulder, Fort Collins, Eugene, Ashland, Bend, and Berkeley based on the most recent available data:[1]

[1] The housing affordability ratios are approximations based on 2025 data and assume median household incomes of ~$96K (Boulder), ~$93K (Fort Collins), ~$73K (Eugene), and ~$97K (Berkeley). They reflect the growing challenge of affordability, especially in high-cost markets like Berkeley and Boulder.