Detached casita
A standalone structure in the side or rear yard with its own foundation, roof and utilities. Offers the most privacy and the clearest rental potential, and is the form most cities regulate as a detached ADU.
Detached casita guide
The casita home guide
Casita Homes, explained from the ground up
Small houses. Real square footage. Built for guests, family and rental income.
Casita Homes is an independent resource for anyone researching, planning or building a casita. We cover what a casita home actually is, how much one costs, which floor plans work, what permits you will need, and how detached guest houses compare with attached suites and prefab units.
300 to 1,200Typical square feet
Attached or detachedTwo main layouts
ADU in most citiesHow zoning treats it
A detached backyard casitaThe most common form in Arizona, Texas and California
Definition
What is a casita home?
Casita, from the Spanish for "little house," pronounced kah-SEE-tah.
A casita home is a small, self-contained dwelling that shares a lot with a larger primary residence. It has its own entrance and, in almost every case, its own bathroom. Many include a kitchenette or full kitchen, a sleeping area and a living space, which is what separates a casita from a spare bedroom or a converted garage that still relies on the main house.
The word comes from the Spanish-speaking Southwest, and that is still where casita homes are most common. In Arizona, New Mexico, Nevada, Texas and Southern California, a casita is an ordinary feature of suburban lots, new master-planned communities and older adobe neighbourhoods alike. Builders in these markets often offer a casita as a standard floor plan option rather than a custom addition.
In planning and zoning language, a casita home is usually classified as an accessory dwelling unit, or ADU. The terms overlap but are not identical: ADU describes a legal category that includes garage apartments, basement units and backyard cottages anywhere in the country, while casita describes a regional building tradition and a particular style of small, single-storey living space, often with a courtyard or covered patio connecting it to the main house.
People build casita homes for three practical reasons. They house visiting or ageing family with privacy on both sides. They generate rental income from a long-term tenant or short-term guests where local rules allow. And they add usable, permitted square footage that increases the value of the property without the cost or disruption of a full second-storey addition.
Casita vs guest house
A guest house is any secondary building used for visitors. A casita is a guest house with complete living facilities, so the terms are often used interchangeably in the Southwest.
Casita vs ADU
Every casita is an ADU for permitting purposes, but not every ADU is a casita. ADU is the legal label; casita is the building type.
Casita vs in-law suite
An in-law suite is typically inside or attached to the main house and may share its kitchen. A casita has independent facilities, whether attached or detached.
Casita vs tiny home
A tiny home is usually moveable and built to RV or park-model standards. A casita is a permanent structure built to the residential code on a foundation.
Independence is the defining feature. If a space cannot function on its own for sleeping, bathing and basic cooking, it is a room, not a casita home.
Casita Homes editorial note
Types of casita homes
Three ways a casita is built
The layout you choose affects cost, permits, privacy and resale more than any finish decision. Most projects fall into one of three categories.
Attached casita
Shares a wall, a roofline or a courtyard with the main house but keeps a separate exterior entrance. Common in production homes across Arizona and Texas, where it is sold as a "casita plan" or "next-gen suite."
Attached casita guide
Prefab casita
Factory-built modular or panelised units delivered to the site and set on a prepared foundation. Faster to install and more predictable on price, with a growing number of manufacturers targeting the casita and ADU market.
Prefab casita guide
Why people build them
The case for a casita home
Casita homes have moved from a regional tradition to a national planning conversation. As housing costs rise and families stretch across generations, a small, independent dwelling on an existing lot solves several problems at once.
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Multigenerational living
Parents, adult children or a caregiver can live on the property with a door they control.
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Rental income
Where zoning permits, a casita can carry a long-term lease or short-term bookings and offset a mortgage.
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Property value
Permitted, conditioned square footage with a kitchen and bath is counted by appraisers and sought by buyers.
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Flexible space
Home office, studio, guest quarters or a place to downsize into while renting out the main house.
Cost and permits
What a casita home involves
Every figure on this site is traced to a source: municipal fee schedules, state ADU statutes, builder price sheets and published cost surveys. These are the ranges most projects land in.
$150 to $400Per square foot, site-built
Varies with region, finish level and whether utilities already reach the site.
$80k to $250kTypical all-in project range
From a compact prefab studio to a custom 1,000 sq ft detached casita.
4 to 12 monthsPermit to completion
Prefab units shorten the build; permitting time depends on the city.
5 to 10 ftCommon rear setback
Most Southwest cities allow reduced setbacks for detached ADUs under a height limit.
Ranges are illustrative. Our cost and permit guides break these down by state and city with citations.
Start here
Casita home guides
Reference articles organised the way a project actually unfolds: understand, price, plan, permit, build.
How much does a casita home cost?
Per-square-foot ranges, attached vs detached, prefab vs site-built, and the line items people forget.
Read the cost guideCasita floor plans by size
Studio, one-bedroom and two-bedroom layouts from 300 to 1,200 square feet, with what each size does well.
See the plansCasita permits and zoning
Setbacks, size caps, owner-occupancy rules and ADU statutes in Arizona, Texas, California, Nevada and New Mexico.
Check the rulesPrefab casita homes compared
Manufacturers, base prices, delivery regions and what is and is not included in a quoted price.
Compare units
About this site
Written by people who read the zoning code
Casita Homes is written from a planning and real estate background. We read municipal codes, state statutes and builder specifications directly, draw our own site plans and diagrams, and say plainly when a figure is an estimate rather than a fact.
- Every cost and permit figure links to its source
- Original diagrams for setbacks, plans and lot layouts
- Guides reviewed and updated as city rules change
- Clear disclosure on any product or plan recommendation
