What people mean by “casita” in Austin
The Spanish word casita literally translates to “little house,” and that's a reasonable working definition. In practice, when someone in Austin says casita, they usually mean a second small dwelling on the same lot as their main house. Sometimes detached, occasionally attached, sometimes above a garage. From the Travis County Appraisal District's perspective, every one of those is an ADU. The terms are interchangeable here.
The casita name often carries a connotation — a guest house, a backyard retreat, something modest and architecturally distinct from the main house. That's an aesthetic decision, not a regulatory one. The city of Austin doesn't treat “casita” and “ADU” differently. The same HOME amendment rules, the same impervious-cover caps, the same setback math.
