One Property, Two Generations: Why Arizona Homeowners Are Turning to Casitas
For generations, the American housing dream followed a fairly predictable pattern.
You grew up. You moved out. You bought a house. Your parents stayed in theirs. Eventually, your children did the same.
Today, that equation doesn’t work quite as neatly.
Housing costs have risen. Adult children are staying home longer or returning home. Aging parents may need to live closer to family without necessarily wanting to give up their independence. Meanwhile, homeowners throughout Phoenix and Tucson are looking at the unused space on their own properties and asking a surprisingly practical question:
Could we just build another living space here?
Increasingly, the answer may be yes.
Casitas—also known as accessory dwelling units, or ADUs—are becoming an increasingly attractive option for Arizona homeowners looking to accommodate multiple generations while preserving something everybody values: A little privacy.
Multigenerational Living Isn’t a Niche Anymore
The American household has been quietly changing for decades.
According to a 2026 Pew Research Center analysis of U.S. Census data, 22% of Americans lived in multigenerational households in 2024, compared with only 13% in 1970.
That’s roughly one out of every five Americans.
The reasons vary tremendously.
An aging parent may want to be closer to children and grandchildren. An adult child may be saving for a first home. Grandparents may help with childcare. A family member may need temporary assistance after a major life change.
And sometimes it simply makes financial sense to combine resources.
But there’s an important distinction between living together and wanting to spend every waking moment together.
That’s where the casita becomes interesting.
What Exactly Is a Casita?
In Arizona, the term “casita” is commonly used for what building and zoning departments call an Accessory Dwelling Unit (ADU).
Think of it as a smaller, independent residence located on the same property as the primary home.
Depending upon the property, design and local regulations, a casita can include its own bedroom, bathroom, living space and full kitchen. It may be detached from the main residence or incorporated into a larger residential design.
In Phoenix, for example, the city describes ADUs—also commonly called guest houses or casitas—as independent living areas with their own kitchen, bathroom, living area and sleeping quarters.
That’s significantly different from simply putting a bed in a spare bedroom.
You’re creating a home within the property.
Why Casitas Make Sense for Aging Parents
Imagine an aging parent who can still live independently but no longer wants to maintain a large home.
They don’t necessarily need assisted living.
They don’t necessarily want to move into their child’s guest bedroom, either.
A thoughtfully designed casita creates a middle ground.
Mom or Dad can have a private entrance, kitchen, bathroom, bedroom and living area while being only a few steps away from family.
And the design can anticipate future needs.
A curbless shower, wider doorways, minimal thresholds, lever-style handles, appropriate lighting and adequate maneuvering space can make a casita considerably more comfortable as its occupant ages.
Tucson has specifically recognized this benefit. The city’s ADU planning materials identify casitas as a tool that can provide affordable housing options for older adults while supporting aging in place and proximity to family and caregivers.
That’s an important concept: Close enough to help. Separate enough to remain independent.
What About Adult Children?
Now flip the equation.
A recent college graduate lands a good job but isn’t ready to purchase a home. A divorced son or daughter needs somewhere to regroup. A young couple wants to save money before entering the housing market.
Moving back into their childhood bedroom isn’t particularly appealing at 28.
A casita changes the dynamic.
An adult child can have a genuine residence while the family shares the cost and advantages of a single property.
And years later, that same structure might serve an entirely different purpose.
That’s one of the strongest arguments for considering a casita as part of a long-term Arizona home renovation strategy.
Today’s Casita Doesn’t Have to Be Tomorrow’s Casita
Suppose you build one because your 27-year-old daughter needs somewhere to live.
Five years later, she buys her own home.
What happens to the casita?
It could become space for visiting relatives. A private guest suite. An office. Housing for another family member. Eventually, it might provide a place for an aging parent.
And years from now?
Perhaps you live there while the next generation occupies the main house.
That’s why the best casita designs shouldn’t only solve today’s problem.
They should consider what the family may need 10, 20 or even 30 years from now.
Arizona’s Rules Are Changing, Too
This is where homeowners should talk with a knowledgeable contractor and local planning department before assuming that something they saw online can simply be built in their backyard.
Phoenix changed its ADU regulations in late 2024 to comply with changes in Arizona law. Under current Phoenix rules, properties with no more than one detached single-family primary residence can generally have two ADUs, with a third possible under certain circumstances. Size allowances depend upon the main home’s floor area and lot size.
Phoenix is also developing a library of pre-approved standard ADU plans, intended to reduce design barriers and make the permitting process more accessible. Those plans were still listed as being under review on the city’s website as of August 2026.
Tucson also permits casitas on residential properties subject to applicable zoning, size, setback, height and other development requirements.
The important takeaway isn’t that every homeowner can build whatever they want.
It’s that Arizona’s housing environment has become considerably more accommodating to ADUs—and homeowners have more options worth exploring.
Before You Build a Casita, Look at the Entire Property
Here’s where a casita project becomes much more than choosing a floor plan.
Where will it sit?
How will someone access it?
Where will water, sewer and electrical service come from?
What about HVAC?
Does the lot have easements?
How will the new structure affect the backyard, parking, drainage and privacy?
Are there HOA restrictions?
Will the architecture complement the existing house?
And if an aging parent will occupy it, should accessibility features be incorporated now rather than retrofitted later?
Those questions are why a casita builder in Phoenix or Tucson should look at the entire property—not simply the square footage of the proposed structure.
In fact, Phoenix specifically advises homeowners in HOA communities to check their association’s rules regarding accessory structures.
Sometimes You Don’t Need a Separate Building
Here’s another possibility homeowners often overlook.
The answer may already be inside the house.
A garage conversion, addition, reconfigured bedroom wing or underused portion of a large home may sometimes be transformed into a more independent living area.
For families considering multigenerational home remodeling, the first question therefore shouldn’t necessarily be:
“Where should we put the casita?”
It should be:
“How can this property work better for our family?”
The answer might be a detached ADU.
Or an addition.
Or a major interior renovation that creates two comfortable living environments under one roof.
That’s where planning becomes more important than simply building square footage.
Maybe the Home You Need Is the One You Already Own
For families navigating today’s housing economy, the solution isn’t always buying a bigger house.
Sometimes it’s making better use of the property they already have.
A well-designed casita can provide independence for aging parents, breathing room for adult children and flexibility for a family’s changing needs.
And unlike many remodeling projects designed primarily around aesthetics, an ADU can fundamentally change how a family uses its property for decades.
At AZ Construction & Renovation, we help homeowners throughout Phoenix, Tucson and surrounding Arizona communities explore renovation, addition and new-construction solutions designed around the way they actually live.
Because sometimes creating room for the next chapter doesn’t require moving.
It just requires looking at home a little differently.