More Homes, More Choices: Tucson’s Missing Middle Goes to Council

Valerie Lane
Dec 3, 2025
3 min read

From Backyard Dreams to Citywide Change

A grassroots path to abundance in Tucson

Dear UIP Community,

A major housing policy update is coming before the Mayor and Council on December 16, 2025, and it could shape the next decade of small-scale housing development, ADUs, and micro-communities in Tucson. As many of you know, UIP has now helped more than 30 Tucson families design and move forward with ADUs—proof that our local, homegrown infill ecosystem is not only possible, but thriving.

Below is a breakdown of what’s happening, why it matters, and how UIP is preparing for the shift to the 2024 City and County building codes on January 1, 2026.

We would also appreciate your support for these changes; please consider sharing your thoughts with the Mayor and Council. They need to hear directly from Tucson Residents who have built an ADU and are positively benefiting from the flexibility an extra little house can offer!

Below is a breakdown of what’s happening, why it matters, and how UIP is preparing for the shift to the 2024 City and County building codes on January 1, 2026.

Upcoming Vote: Missing Middle Housing Bill

On December 16, the City of Tucson will discuss and vote on a set of zoning tools that affect:

Minimum lot sizes
How many units can be built on a parcel
Whether homeowners can subdivide “parent lots” into smaller “unit lots” to promote homeownership
How accessible small-scale development will be scaled for Tucson families—not just large developers

These changes directly support the kind of local, homeowner-driven infill development that UIP was created to empower.

Why This Matters to You

If passed as recommended:

Most residential lots could be split into four smaller unit lots—each eligible for one home.
- R1: 6,000 sf → four 1,500 sf unit lots
- R2/R3: 4,000 sf → four 1,000 sf unit lots
All development stays at a residential scale (no commercial civil engineering or commercial parking requirements).
Homeowners can sell units individually, making construction dramatically more accessible and reducing long-term reliance on rental portfolios.
This opens the door for micro-communities, intergenerational living, and local wealth-building through housing—the exact outcomes Tucson families repeatedly tell us they want.

What UIP Advocates For

As a Ward 5 Planning Commissioner, I (Valerie) moved to approve the Missing Middle Housing proposal with two additions that I believe make the policy stronger and more equitable:

No physical boundary limiting where the bill applies. Instead of creating an exclusionary “allowed zone,” the Commission recommended a citywide, two-year review. This ensures transparency, fairness, and meaningful data.
Lot subdivision based on unit count, not just minimum lot size. This is the most powerful part: it lets homeowners and small builders subdivide without triggering commercial requirements—something impossible under the current zoning model.

Together, these tools form the foundation of a local small-scale development industry driven by residents, families, small builders, and neighborhood-based investment.

For all the details, see our Full Letter to Mayor & Council:

UIP Plan Updates: Transition to the 2024 Building Codes

Both the City of Tucson and Pima County will adopt the 2024 International Residential Building Codes on January 1, 2026.

UIP is already in the middle of updating our entire ADU plan library to meet these new requirements.

What This Means for You

Plans submitted before January 1 can still use the older code set.
Plans submitted after January 1 must conform to the new 2024 codes.

We are also developing a new pre-approved two-story Duplex - this will be available on our website in early 2026

If you are planning to submit your ADU in early 2026, please reach out—we can help you schedule a smooth transition.

What We’re Seeing on the Ground: A Growing Local ADU Ecosystem

30 ADUs sold to date! → more families building intergenerational living options
Increasing demand for small-scale ownership options instead of rental-only development
More interest in micro-communities, casitas for aging parents, and flexible multigenerational solutions

UIP’s mission remains the same: to make Tucson’s housing ecosystem more predictable, attainable, and resident-driven.

Calls to Action:

Attend the December 16 Mayor & Council Meeting

Email Mayor & Council (Citycleark@tucsonaz.gov)
Reach out to UIP with questions about how the proposed tools could apply to your property or your neighborhood

This is a big moment for Tucson—and your voice matters.

Journal questions:

What systemic barriers have I witnessed that most clearly prevent everyday Tucsonans from building generational stability?
How would Tucson look and feel if residents—not large developers—were the primary builders of new housing?
What stories from Tucson families resonate most with the vision of micro-communities, multigenerational living, and shared spaces?
How do small-scale housing solutions change the social fabric of a neighborhood?
Feel free to share your answers with us! info@infillproject.com

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Dear UIP Community,

Below is a breakdown of what’s happening, why it matters, and how UIP is preparing for the shift to the 2024 City and County building codes on January 1, 2026.

We would also appreciate your support for these changes; please consider sharing your thoughts with the Mayor and Council. They need to hear directly from Tucson Residents who have built an ADU and are positively benefiting from the flexibility an extra little house can offer!

Below is a breakdown of what’s happening, why it matters, and how UIP is preparing for the shift to the 2024 City and County building codes on January 1, 2026.

On December 16, the City of Tucson will discuss and vote on a set of zoning tools that affect:

Minimum lot sizes

How many units can be built on a parcel

Whether homeowners can subdivide “parent lots” into smaller “unit lots” to promote homeownership

How accessible small-scale development will be scaled for Tucson families—not just large developers

These changes directly support the kind of local, homeowner-driven infill development that UIP was created to empower.

If passed as recommended:

Most residential lots could be split into four smaller unit lots—each eligible for one home.

R1: 6,000 sf → four 1,500 sf unit lots

R2/R3: 4,000 sf → four 1,000 sf unit lots

All development stays at a residential scale (no commercial civil engineering or commercial parking requirements).

Homeowners can sell units individually, making construction dramatically more accessible and reducing long-term reliance on rental portfolios.

This opens the door for micro-communities, intergenerational living, and local wealth-building through housing—the exact outcomes Tucson families repeatedly tell us they want.

As a Ward 5 Planning Commissioner, I (Valerie) moved to approve the Missing Middle Housing proposal with two additions that I believe make the policy stronger and more equitable:

No physical boundary limiting where the bill applies. Instead of creating an exclusionary “allowed zone,” the Commission recommended a citywide, two-year review. This ensures transparency, fairness, and meaningful data.

Lot subdivision based on unit count, not just minimum lot size. This is the most powerful part: it lets homeowners and small builders subdivide without triggering commercial requirements—something impossible under the current zoning model.

Together, these tools form the foundation of a local small-scale development industry driven by residents, families, small builders, and neighborhood-based investment.

For all the details, see our Full Letter to Mayor & Council:

Both the City of Tucson and Pima County will adopt the 2024 International Residential Building Codes on January 1, 2026.

UIP is already in the middle of updating our entire ADU plan library to meet these new requirements.

What This Means for You

Plans submitted before January 1 can still use the older code set.

Plans submitted after January 1 must conform to the new 2024 codes.

If you are planning to submit your ADU in early 2026, please reach out—we can help you schedule a smooth transition.

30 ADUs sold to date! → more families building intergenerational living options

Increasing demand for small-scale ownership options instead of rental-only development

More interest in micro-communities, casitas for aging parents, and flexible multigenerational solutions

UIP’s mission remains the same: to make Tucson’s housing ecosystem more predictable, attainable, and resident-driven.

Calls to Action:

Attend the December 16 Mayor & Council Meeting

Email Mayor & Council (Citycleark@tucsonaz.gov)

Reach out to UIP with questions about how the proposed tools could apply to your property or your neighborhood

This is a big moment for Tucson—and your voice matters.

Journal questions:

What systemic barriers have I witnessed that most clearly prevent everyday Tucsonans from building generational stability?

How would Tucson look and feel if residents—not large developers—were the primary builders of new housing?

What stories from Tucson families resonate most with the vision of micro-communities, multigenerational living, and shared spaces?

How do small-scale housing solutions change the social fabric of a neighborhood?