Rental numbers for ZIP 78666 (San Marcos, TX)
Negative cash flow at any interest rate with 25% down: the rent does not cover operating costs and principal.
- Gross yield
- 5.5%
- rent x 12 / price
- Est. cap rate
- 1.3%
- NOI / price
- Cash flow
- -$1,344/mo
- at 7.78%, 25% down
- Typical price
- $312,000
- Zillow ZHVI, Aug 2026
- Typical rent
- $1,414/mo
- Zillow ZORI, Aug 2026
The pro forma
Typical home, default assumptions
| Operator | Line | Amount | Source |
|---|---|---|---|
| Gross rent | $16,968 | ||
| Vacancy | $848 | ||
| Management | $1,290 | ||
| Property tax | $4,259 | ||
| Insurance | $3,437 | ||
| Maintenance | $3,116 | ||
| Net operating income | $4,018 | ||
| Loan payments | $20,147 | ||
| Cash flow | -$16,128 |
| Operator | Line | Amount | Source |
|---|---|---|---|
| Typical price | $311,558 | ||
| Down payment (25%) | $77,890 | ||
| Loan | $233,669 | ||
| Rate | 7.78% | ||
| Monthly payment | $1,679 | ||
| Cash in | $87,236 | ||
| Cash-on-cash return | -18.5% | ||
| DSCR | 0.20 | ||
| Break-even rate | none |
Assumptions
Change them in the calculator- Down payment25%
- A common minimum for investment-property and DSCR loans.
- Interest rate7.78%
- Freddie Mac 30-year 7.03% (week of 2026-09-24) + 0.75 point investor premium.
- Loan term30 years
- Fixed, fully amortising.
- Closing costs3% of price
- Added to cash invested.
- Insurance$3,437 a year
- NAIC 2023 average homeowners (HO-3) premium for Texas, $2,864, x 1.2 for a landlord policy.
- Maintenance1% of price a year
- The 1% rule of thumb; older homes run higher.
- Vacancy5% of rent
- About 18 days empty a year.
- Management8% of collected rent
- A typical full-service fee; zero if you self-manage.
Trends
Five years to August 2026
- Price, 12 months
- -3.3%
- Rent, 12 months
- -0.1%
- Rent minus price growth
- +3.2 pts
- positive means yields are improving
Show the numbers
| Month | Typical value | Rent |
|---|---|---|
| Aug 2021 | $332,201 | $1,337 |
| Aug 2022 | $393,644 | $1,476 |
| Aug 2023 | $356,498 | $1,493 |
| Aug 2024 | $339,463 | $1,499 |
| Aug 2025 | $322,158 | $1,415 |
| Aug 2026 | $311,558 | $1,414 |
Rent references
Two sources, never blended
| Source | Studio | 1 bed | 2 bed | 3 bed | 4 bed |
|---|---|---|---|---|---|
| HUD Small Area FMR, FY2026 | $1,170 | $1,250 | $1,480 | $1,880 | $2,200 |
| Zillow observed rent, Aug 2026 | $1,414 typical, all home types | ||||
HUD's Fair Market Rent is the 40th percentile gross rent (rent plus utilities) for a standard unit, and it is what Section 8 vouchers pay against. Zillow's index tracks asking rents on listed homes. The two measure different things, so they are shown side by side and never averaged. HUD area: Austin-Round Rock-San Marcos, TX MSA.
Property tax
- Effective rate
- 1.37%
- ZIP area, ACS
- At the typical price
- $4,259/yr
Median real estate taxes paid divided by median home value, Census ACS 2020 to 2024. Hays County: 1.66%. Actual bills depend on the assessment, exemptions and any non-homestead rate.
Supply
- Permits per 1,000 households
- 45.7
- Hays County, last 12 months
- National percentile
- 99th
- among US counties
4,562 new housing units permitted in 2025-09 to 2026-08, Census Building Permits Survey. A high figure means more new supply competing for tenants.
Nearby ZIP codes
| ZIP | Distance | Typical price | Rent | Gross yield | Cash flow /mo |
|---|---|---|---|---|---|
| 78655Martindale | 10.1 mi | $338,000 | $1,300* | 4.6% | -$1,571 |
| 78656Maxwell | 10.7 mi | $254,000 | $1,868 | 8.8% | -$570 |
| 78640Kyle | 12.5 mi | $293,000 | $1,566 | 6.4% | -$1,176 |
| 78130New Braunfels | 13.9 mi | $304,000 | $1,577 | 6.2% | -$1,127 |
| 78622Luling | 14.1 mi | $235,000 | $1,760* | 9.0% | -$399 |
| 78623Blanco | 14.8 mi | $486,000 | $1,420* | 3.5% | -$2,409 |
| 78132New Braunfels | 15.0 mi | $556,000 | $1,602 | 3.5% | -$2,866 |
| 78676Wimberley | 15.1 mi | $557,000 | $2,023 | 4.4% | -$2,517 |
* HUD Fair Market Rent, 2 bedroom (no Zillow rent index for that ZIP).
Run the numbers on a real listing
The calculator opens with this ZIP's figures. Swap in a listing's price and rent, your rate and your costs.
Open the calculator for 78666Questions
- Is 78666 good for rental property?
- On the typical home here, priced at $312,000 and renting for $1,414 a month (Zillow ZORI, Aug 2026), the gross yield is 5.5% and the estimated cap rate is 1.3%. At a 7.78% investor rate with 25% down, estimated cash flow is -$1,344 a month. The median gross yield across the 8,418 ZIP codes with full Zillow data is 5.6%. These are figures for a typical property, not a judgement on any particular one.
- What is the typical rent in 78666?
- Zillow's observed rent index for 78666 was $1,414 a month in August 2026, across all home types. HUD's FY2026 Small Area Fair Market Rent for a 2-bedroom here is $1,480, the 40th percentile of gross rents and the basis for Section 8 payment standards.
- What is the property tax rate in 78666?
- The effective property tax rate is about 1.37% of value (median taxes paid divided by median home value, Census ACS 2020 to 2024). On the typical $312,000 home that is about $4,259 a year. Your bill depends on the assessment and local exemptions.
- What interest rate makes a rental in 78666 break even?
- With the default assumptions, no interest rate brings cash flow to zero: rent does not cover operating costs plus principal on a 30-year loan with 25% down.
- How fast are prices and rents changing in 78666?
- Over the 12 months to August 2026, the typical home value changed -3.3% and the typical rent changed -0.1%. Rents rising faster than prices pushes yields up.
Sources and method
- Zillow Home Value Index (ZHVI), mid tier, smoothed and seasonally adjusted
Zillow Research. Read: 2026-08.
Typical home value by ZIP, county, metro and state, and the price trend.
- Zillow Observed Rent Index (ZORI), all homes plus multifamily, smoothed
Zillow Research. Read: 2026-08.
Typical market rent by ZIP, county and metro, and the rent trend (tier A pages).
- HUD Small Area Fair Market Rents, FY2026
US Department of Housing and Urban Development. Read: FY2026.
Rent by bedroom count for every ZIP. The rent used on tier B pages, and a reference on all pages. It is the 40th percentile gross rent, so it runs below market.
- American Community Survey 5-year estimates, 2020 to 2024 (B25103 median real estate taxes paid, B25077 median home value, B11001 households)
US Census Bureau. Read: 2020 to 2024.
Effective property tax rate (median taxes paid divided by median value) by ZIP code tabulation area, county and state; households for the permits ratio.
- Freddie Mac Primary Mortgage Market Survey, 30-year fixed (FRED series MORTGAGE30US)
Freddie Mac via the Federal Reserve Bank of St. Louis. Read: 2026-09-24.
The weekly 30-year rate. The site adds a disclosed investor premium to it for the loan payment.
- Building Permits Survey, county monthly files
US Census Bureau. Read: 2025-09 to 2026-08.
New housing units permitted in the last 12 months per 1,000 households, a supply-pressure signal.
- NAIC Homeowners Insurance Report, data for 2023
National Association of Insurance Commissioners. Read: 2023.
Average HO-3 homeowners premium by state, multiplied by 1.2 as a landlord-policy assumption.
Data: Zillow Research (ZHVI, ZORI), HUD, US Census Bureau, Freddie Mac. Every formula is on the methodology page.
Estimates from public data for a typical property. Not investment, tax or legal advice. Your property, financing and costs will differ.