Measured first, the IRS corridor flow from Austin to San Antonio was 6,106 tax-return households, represented by 10,084 exemptions as a people proxy, with $72,680.48 of AGI per return. That is evidence of filed tax-return households changing counties within this market corridor; it does not identify renters, every mover, or future housing demand. It nevertheless gives the direction a firm base: San Antonio received a substantial stream of filing households from Austin, so this is not merely a hypothetical comparison between unrelated metros.
For household housing costs, San Antonio resets the nominal baseline downward. At the end-June Zillow observation, asking rent was $1,416 in San Antonio versus $1,653 in Austin, while home values were $280,370 versus $426,944. Income also changes: the ACS median was $76,213 in San Antonio and $100,431 in Austin. BEA’s housing price parity was 94.575 at the destination versus 120.361 at the origin. These Zillow, ACS, and BEA readings come from different source periods, so they are directional rather than a synchronized household budget. A mover keeping Austin-linked pay faces different arithmetic from someone taking locally priced San Antonio work.
For rental-property underwriting, the destination begins with a higher simple gross-yield screen, 6.06% versus 4.65%, but a weaker recent payroll signal, 0.10% versus 1.39%. That changes the central question from whether San Antonio is cheaper to whether achievable effective rent adequately covers the asset’s full cost structure. The next underwriting question is: after property tax, insurance, including inland-flood exposure, maintenance, vacancy, concessions, management, and financing, what stabilized net operating income and break-even occupancy does the target property and submarket support? Metro averages cannot answer that question or establish a universal winner.

