ZIP CODE 78666 // AUSTIN-ROUND ROCK-GEORGETOWN, TX // DATA AS OF 2026-09-30
San Marcos, TX (78666) Rental Property Cap Rate & Cash Flow Report
Located in Hays County (San Marcos, TX), Zip Code 78666 ranks #308 of 500 within this selected sample (39th percentile) with a Zillow ZHVI typical home-value index of $309,421 (-2.9% YoY) and a ZORI observed market rent of $1,418/mo (+0.8% YoY). Requires at least 62.9% down payment at 6.5% interest to reach $0/mo break-even cash flow. This model combines different housing populations; it is not an observed average property return. Costs assume state-average tax, 0.5% annual insurance, 13% reserves and no HOA or management. Figures below follow your edits; this headline describes the original benchmark.
Net Monthly Cash Flow
-$839/mo
Annual: -$10,066/yr
Modeled Cap Rate
2.81%
NOI: $8,709/yr
Cash-on-Cash Return
-14.14%
Cash Needed: $71,167
1% Rule Ratio
0.46%
Gross Yield: 5.50%
Break-Even Rent
$2,382/mo
State Tax: 1.47%/yr
INTERACTIVE PRO-FORMA STATEMENT (ZIP 78666 BENCHMARK)
Edit any value
Purchase Price (ZHVI proxy)
Monthly Gross Rent (ZORI proxy)
Down Payment (%)
Interest Rate (30Y Fixed %)
Annual Property Tax (TX Avg 1.47%)
Annual Home Insurance ($)
Monthly HOA Fee ($)
Monthly Debt Service (P&I)
-$1,565/mo
Monthly Operating Expenses (Tax + Ins + 13% Reserves)
-$692/mo
HISTORICAL ZHVI PRICE VS. ZORI RENT TRAJECTORY (78666)
| Year | ZHVI Value | ZORI Rent | Gross Yield |
|---|---|---|---|
| 2021 | $332,935 | $1,347/mo | 4.86% |
| 2022 | $385,826 | $1,495/mo | 4.65% |
| 2023 | $352,122 | $1,489/mo | 5.07% |
| 2024 | $335,529 | $1,473/mo | 5.27% |
| 2025 | $318,803 | $1,407/mo | 5.30% |
| 2026 | $309,421 | $1,418/mo | 5.50% |
COMPARABLE U.S. RENTAL MARKETS
| Zip / City | Price | Rent | Cap Rate | Cash Flow |
|---|---|---|---|---|
| 77407 Richmond, TX | $372,531 | $1,716/mo | 2.84% | -$1,002/mo |
| 77573 League City, TX | $383,781 | $1,744/mo | 2.77% | -$1,053/mo |
| 77433 Cypress, TX | $422,856 | $1,964/mo | 2.88% | -$1,124/mo |
| 78249 San Antonio, TX | $298,882 | $1,393/mo | 2.90% | -$790/mo |
| 78045 Laredo, TX | $295,277 | $1,381/mo | 2.91% | -$776/mo |
| 75098 Wylie, TX | $417,750 | $1,874/mo | 2.71% | -$1,168/mo |