When I put your values into this calculator (https://tax-office.traviscountytx.gov/properties/property-tax-basics https://tax-office.traviscountytx.gov/properti

When I put your values into this calculator (https://tax-office.traviscountytx.gov/properties/property-tax-basics https://tax-office.traviscountytx.gov/properties/property-ta...), I found that the house in Rollingwood would have about 2K in City of Rollingwood taxes (just as you said), but the house in Austin would only have about 4K in City of Austin taxes, not 20-30K. All other property taxes were the same between the two properties. The overall property tax burden in Austin (adding county, school, etc taxes) for a million dollar house would be 20,298, while in Rollingwood (with the same additional tax categories), it would be 18,388. Certainly the taxes in Rollingwood are lower, but with hardly as big of a gap as you wrote. How did you get your numbers?