ZIP 78663 falls in Travis County, Texas, where we hold 34,543 parcels measured as septic county-wide and 337,990 on sewer. We do not have a per-ZIP parcel count for this county, so this is the county total, not a count specific to ZIP 78663.
ZCTA 78663 is not entirely inside one county. Land-area share is from the 2020 Census ZCTA-to-county relationship file.
| County | Land in this ZIP | Documents held | On septic (county) | On sewer (county) |
|---|---|---|---|---|
| Travis County, Texas | 4% | 164,420 | 34,543 | 337,990 |
| Hays County, Texas | 2% | 2 | 56,993 | 32,829 |
| Burnet County, Texas | 1% | — | — | — |
Land-area overlap is from the 2020 Census Bureau ZCTA5-to-county relationship file, not an estimate of ours. Parcel and document counts are rows we hold, not a survey of every property in the ZIP. Last verified 2026-09-01.
We hold 34,543 parcels measured as septic for Travis County, Texas as a whole, not broken out by ZIP.
ZIP 78663 spans 3 counties: Travis County, Texas, Hays County, Texas, Burnet County, Texas.