SF-2 zoning in Austin: how it differs from SF-3 (barely)
| Standard | SF-2 | SF-3 |
|---|---|---|
| Minimum lot size | 5,750 sq ft | 5,750 sq ft |
| Minimum lot width | 50 ft | 50 ft |
| Maximum dwelling units | 3 | 3 |
| Maximum height | 35 ft | 35 ft |
| Front setback | 25 ft | 25 ft |
| Street side setback | 15 ft | 15 ft |
| Interior side setback | 5 ft | 5 ft |
| Rear setback | 10 ft | 10 ft |
| Building coverage | 40% | 40% |
| Impervious cover | 45% | 45% |
| Floor-to-area ratio | none | none |
Not an error in the table — the SF-2 and SF-3 columns of §25-2-492 are identical in every row. We checked them cell by cell.
The entire difference was four words
If you are here because you want to know how SF-2 differs from SF-3, the answer is shorter than you expect. The two designations, side by side:
§25-2-56 (SF-2) — "the designation for a moderate density single-family residential use on a lot that is a minimum of 5,750 square feet."
§25-2-57 (SF-3) — "the designation for a moderate density single-family residential use and a duplex use on a lot that is a minimum of 5,750 square feet."
That is it. Same lot size, same everything downstream. SF-3 permitted a duplex; SF-2 did not. Every dimensional standard in §25-2-492 has always been identical between them, and still is.
The designation text has not caught up
Worth knowing if you read the code yourself and get confused. §25-2-56 still describes SF-2 as single-family only — its Source line shows it was last amended by Ordinance 031211-11, which is 2003. HOME did not go back and rewrite the designation sections; it changed the permitted use table in §25-2-491.
So the code now says two things. The designation section describes a single-family-only district. The use table permits duplex, two-unit and three-unit residential in it.
The use table governs. Designation sections describe what a district is for and guide how it gets applied in a rezoning; the permitted use table controls what may be built. But if you have read §25-2-56 and concluded you cannot build a duplex on SF-2, that is where the confusion came from.
What actually varies your SF-2 lot
Since the district tells you so little, these are the things that do:
- Subchapter F — inside the boundary a single dwelling gets a 0.4 floor area cap, 32 ft height rather than 35, and the setback tent.
- Unit count — two or three units moves you to §25-2-773 and a different floor area gradient.
- Overlays — a neighbourhood plan combining district can modify maximum FAR, maximum gross floor area and the minimum front yard setback.
- Watershed — can set an impervious cover limit below 45%.
Does SF-2 vs SF-3 change anything for us?
In design, no. We work the same way on both. The lot dimensions, the Subchapter F question and the watershed set the house; the district letter does not.
Where it still shows up is in older documents and in people's expectations. Sellers and agents sometimes describe SF-3 as "the one that allows two units" — that framing is out of date, and it can affect what someone thinks a lot is worth. If you are buying an SF-2 lot on the assumption you cannot build a second unit, check the current use table before you price it.
Common questions
Working out what you can build?
We build in Central Austin and deal with this code on every project. If you own a lot and want a straight answer about what fits on it, we're happy to take a look.
Talk to us about your lotWe are homebuilders, not the City of Austin. This page explains how we read the code in practice — it is not legal advice and it is not an official determination. Always confirm with Austin Development Services before you rely on it for a project. The authoritative text is the Austin Land Development Code; permitting questions go to Austin Development Services Department.