ZIP 78729 falls in Williamson County, Texas, where we hold 110,116 parcels measured as septic county-wide and 176,652 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 78729.
ZCTA 78729 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) |
|---|---|---|---|---|
| Williamson County, Texas | 88% | — | 110,116 | 176,652 |
| Travis County, Texas | 12% | 164,420 | 34,543 | 337,990 |
3 businesses on record with an address in this ZIP: pumping, installation, design, inspection and repair. Not an endorsement, and we take no fee.
| Company | City | Phone | Rating |
|---|---|---|---|
| Allstar Realty Inspections | Austin | (512) 937-7507 | 5.0 (8) |
| RC's Plumbing Company | Austin | (512) 736-8870 | 4.0 (18) |
| Spartan Plumbing | Austin | (512) 888-3636 | — |
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 110,116 parcels measured as septic for Williamson County, Texas as a whole, not broken out by ZIP.
ZIP 78729 spans 2 counties: Williamson County, Texas, Travis County, Texas.