The standard residential spec around Austin is 5-inch gutter with 2×3 downspouts. It fits most homes fine. But "most homes" is doing some work in that sentence, and the newer neighborhoods around the metro are full of houses it doesn't fit.
What actually decides it
A gutter's job is to catch everything a roof plane sheds in a hard storm and move it to a downspout before it goes over the edge. Three things set how much water that is:
- Roof area draining into the run. Not the footprint of the house — the actual square footage of roof feeding each specific gutter run.
- Pitch. Steeper roofs shed water faster, so the gutter has to swallow the same volume in less time.
- Downspout capacity. A gutter is only as good as its exits. A 3×4 downspout moves roughly twice the water of a 2×3.
Central Texas rain arrives in bursts — an inch can come down in well under an hour. A gutter that handles a gentle all-day rain can still sheet over the front edge in a May storm cell.
Why newer homes push the number up
The newer sections around Leander, Georgetown, Kyle, and the rest tend toward two-story homes with big, steep, consolidated roof planes. One long back run might drain more roof than an entire older single-story house. That's 6-inch, 3×4-downspout territory — not as an upsell, as arithmetic.
How you find out
You measure. At the estimate we walk the roofline, measure what drains into each run, and spec each one. Sometimes that means 6-inch on the back and 5-inch everywhere else — the house gets what each plane needs, not a blanket answer.
If someone quotes your gutters over the phone without knowing your roof, they're guessing about exactly this. More on that in why we don't do phone ballparks. To get your roof actually measured, book the free estimate.