Back to Blog Casita / ADU ADU vs Casita vs Guest House: What San Antonio Homeowners Need to Know
Mark WhiteJune 17, 20267 min read Same Structure, Different Names
If you've been researching building a secondary structure on your San Antonio property, you've probably come across a confusing mix of terms: ADU, casita, guest house, granny flat, in-law suite, mother-in-law suite, backyard cottage, accessory apartment. The good news? In San Antonio, they all refer to essentially the same thing.
An ADU (Accessory Dwelling Unit) is the official planning and zoning term used across the country. A casita is the local San Antonio term used by the City's incentive program. Guest house, granny flat, in-law suite, and backyard cottage are informal names that describe the same type of structure. All of them are small, self-contained homes built on the same lot as your primary residence, with their own kitchen, bathroom, living space, and entrance.
What San Antonio Calls Them: The Casita Program
In San Antonio, the City government uses the term 'casita' for its incentive program. The City of San Antonio Casita Incentives Pilot Program offers up to $35,000 in forgivable loans to help homeowners build these units on their property.
Whether you call it an ADU, a casita, a guest house, or a granny flat, the City's program applies. The key requirement is that it's an accessory dwelling unit on your existing residential lot. Legacy Home Improvements is on the City's official Casita Contractor List and uses both terms interchangeably with our clients.
Types of ADUs / Casitas You Can Build in San Antonio
San Antonio zoning allows several configurations for your accessory dwelling unit:
- Detached casita: A standalone structure in your backyard, separated from the main house. This is the most common type and what most people picture when they think of a casita or guest house.
- Attached casita: A unit built as an addition to your main house with its own separate entrance, kitchen, and bathroom. Shares a wall with the primary residence.
- Garage conversion: Converting an existing garage into a living unit. This can be cost-effective if the structure is already sound.
- Above-garage unit: Building living space above an existing or new garage. Great for maximizing lot space.
San Antonio Casita / ADU Zoning Rules
San Antonio allows casitas in most residential zoning districts. Key rules to know:
The maximum size is 800 square feet or 50% of the primary home's living area, whichever is less. The property must be owner-occupied (you live on the lot). One ADU is allowed per residential lot. The casita must meet setback requirements for your zoning district. A separate utility connection may be required for detached units.
Zoning can get complicated. Legacy helps you verify your property's eligibility during our free consultation. We check your zoning, lot size, setbacks, and any HOA restrictions before you invest any money.
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Book Your Free Inspection →Why San Antonio Homeowners Are Building Casitas
The casita/ADU trend is booming across San Antonio for several good reasons:
- Rental income: A casita can generate $800 to $1,500+ per month in rental income, depending on size and location.
- Family housing: Provide independent living space for aging parents, adult children returning home, or extended family.
- Property value: Adding a casita typically increases your property value by 20-30% of the construction cost.
- Affordability: With up to $35,000 in City incentives, the barrier to entry is lower than ever.
- Flexibility: Use it as a home office, art studio, or guest suite today, and convert to a rental later.
How to Get Started With Your San Antonio Casita or ADU
Ready to build? Here's the simplest path forward:
Start with a free consultation from Legacy Home Improvements. We'll visit your property, check zoning and eligibility, walk through the City's incentive program, and provide a instant roof estimate. As a contractor on the City of San Antonio's official Casita Contractor List with over 25 years of local experience, we handle everything from plan selection to keys.
Call (210) 272-7272 or visit our Casita Program page to schedule your free consultation. Whether you call it a casita, ADU, guest house, or granny flat, Legacy is here to build it.
MW Mark White
Owner, Legacy Home Improvements · San Antonio since 1999
Mark has been in the roofing business for over 25 years. He personally inspects homes, works with insurance adjusters, and answers every email at mwhite@legacytx.com.
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