Short answer: Across Travis County, some ZIP codes have far more over-assessed homes than others. Our analysis of public TCAD appraisal data found the highest rates in downtown Austin (78701, about 25% of homes) and West Austin, where homes are most often valued above truly comparable nearby properties. In these areas, roughly one in five homes may have grounds for an equal-and-uniform protest.
- 78701 (Downtown Austin) has the highest over-assessment rate at ~25%.
- West Austin ZIPs — 78703 and 78746 — carry the largest dollar gaps.
- Even in lower-ranked ZIPs, thousands of individual homes are over-assessed.
- Over-assessment is measured against comparable homes, not the whole market.
- The only way to know about your home is to check it directly.
Which Travis County ZIP codes are most over-assessed?
We analyzed Travis Central Appraisal District (TCAD) records for hundreds of thousands of Travis County homes and compared each one to truly similar neighboring properties — the same neighborhood, property class, and era of construction. Homes valued more than 10% above the median of their peer group were flagged as likely over-assessed, the same equal-and-uniform standard used in a Texas protest.
The table below shows the ZIP codes with the highest share of over-assessed homes, along with the average estimated gap for the flagged homes in each area.
How we measured over-assessment
Texas law says your home should not be appraised higher than comparable homes around it (Texas Tax Code §41.43(b)(3)). We applied that principle at scale:
- We grouped every residential parcel with truly comparable homes — matched on TCAD neighborhood code, property class, and decade built.
- Within each group, we found the median improvement value per square foot — the market’s read on a fair rate.
- Any home more than 10% above its group’s median was flagged as likely over-assessed, and we estimated its gap.
These are estimates from public data, not official determinations — but they mirror the exact evidence an appraisal review board weighs in a protest.
Why downtown and West Austin top the list
The leading ZIPs share a trait: they contain a wide mix of home values. When a neighborhood packs together older and newer, smaller and larger, or renovated and original homes, TCAD’s mass-appraisal models struggle to value each one fairly — so more homes end up above their comparable median.
That’s why high-value areas like 78703 (Clarksville/Tarrytown) and 78746 (West Lake Hills) not only rank high, but also carry the largest dollar gaps — six figures on average for the flagged homes. In pricier ZIPs, even a modest percentage over-assessment is a lot of money.
What this means for your home
A high ZIP-level rate does not mean your home is over-assessed — and a low rate does not mean it isn’t. Every ZIP on this list has thousands of homes; even the lower-ranked areas contain many over-assessed properties. Over-assessment is decided home-by-home, against your specific comparables.
The only way to know is to check your own address. If your home is valued above its comparable neighbors, that gap is money you may be overpaying in property taxes every year — and it’s the basis for a protest.
Travis County ZIP codes by over-assessment rate (2026)
| ZIP | Area | Homes analyzed | % over-assessed | Avg. estimated gap |
|---|---|---|---|---|
| 78701 | Downtown Austin | 2,657 | 25.1% | $367,000 |
| 78747 | SE Austin / Onion Creek | 6,928 | 21.4% | $45,000 |
| 78703 | West Austin / Clarksville | 5,729 | 18.8% | $191,000 |
| 78746 | West Lake Hills | 8,671 | 17.7% | $299,000 |
| 78739 | Circle C Ranch | 6,670 | 17.1% | $83,000 |
| 78731 | Northwest Hills | 7,848 | 17.0% | $141,000 |
| 78744 | SE Austin / McKinney | 9,953 | 16.7% | $39,000 |
| 78733 | Bee Cave / Cuernavaca | 3,026 | 16.7% | $154,000 |
| 78617 | Del Valle | 4,136 | 16.0% | $29,000 |
| 78759 | NW Austin / Balcones | 9,487 | 15.8% | $63,000 |
- ↑Complete guide: Using County Appraisal Data to Lower Your Property Taxes
- ›Understanding Your Travis County Property Appraisal: Key Factors That Influence Your Home's Value
- ›How Texas Appraisal Districts Calculate Your Home's Value
- ›How to Access TCAD Appraisal Data for Your Travis County Property Tax Protest
Check your home in minutes
Tax Gaps TX has a free home check at app.taxgapstx.com/check — enter your address and, in about a minute, see your estimated over-assessment gap for Travis (TCAD) or Dallas (DCAD) county, based on public appraisal data and comparable homes assessed for less than yours. A specialist can then walk you through the evidence and whether it's worth protesting.
Frequently asked questions
Does a high ZIP-code rate mean my home is over-assessed?
No. Over-assessment is decided home-by-home against your specific comparable properties. A high-ranked ZIP just means a larger share of homes there are over-assessed — your home could be fine, or a home in a low-ranked ZIP could be significantly over-assessed.
What does 'over-assessed' mean here?
We flagged a home as likely over-assessed if its improvement value per square foot was more than 10% above the median of truly comparable homes — same neighborhood, class, and decade built. That's the equal-and-uniform standard used in a Texas protest.
How do I check whether my own home is over-assessed?
Enter your address at app.taxgapstx.com/check. We pull your county's appraisal data, find comparable homes assessed for less, and show your estimated gap — the evidence you'd use to protest.
Is this an official TCAD determination?
No. These are estimates built from public TCAD data for informational purposes. Confirm any figures with the Travis Central Appraisal District before filing a protest.
Tax Gaps TX provides general information, not legal, tax, or financial advice. Deadlines and exemption amounts change; confirm current figures with your county appraisal district or the Texas Comptroller.