Rental numbers for ZIP 21791 (Union Bridge, MD)
Negative cash flow at any interest rate with 25% down: the rent does not cover operating costs and principal.
- Gross yield
- 4.0%
- rent x 12 / price
- Est. cap rate
- 1.1%
- NOI / price
- Cash flow
- -$1,986/mo
- at 7.78%, 25% down
- Typical price
- $447,000
- Zillow ZHVI, Aug 2026
- HUD Fair Market Rent
- $1,490/mo
- HUD Fair Market Rent, 2 bedroom, FY2026
The pro forma
Typical home, default assumptions
| Operator | Line | Amount | Source |
|---|---|---|---|
| Gross rent | $17,880 | ||
| Vacancy | $894 | ||
| Management | $1,359 | ||
| Property tax | $4,204 | ||
| Insurance | $1,894 | ||
| Maintenance | $4,468 | ||
| Net operating income | $5,062 | ||
| Loan payments | $28,889 | ||
| Cash flow | -$23,827 |
| Operator | Line | Amount | Source |
|---|---|---|---|
| Typical price | $446,754 | ||
| Down payment (25%) | $111,689 | ||
| Loan | $335,066 | ||
| Rate | 7.78% | ||
| Monthly payment | $2,407 | ||
| Cash in | $125,091 | ||
| Cash-on-cash return | -19.0% | ||
| DSCR | 0.18 | ||
| 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$1,894 a year
- NAIC 2023 average homeowners (HO-3) premium for Maryland, $1,578, 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
- +1.0%
- Rent, 12 months
- n/a
- no Zillow rent series here
- Rent minus price growth
- n/a
- positive means yields are improving
Show the numbers
| Month | Typical value |
|---|---|
| Aug 2021 | $376,435 |
| Aug 2022 | $401,206 |
| Aug 2023 | $408,906 |
| Aug 2024 | $429,963 |
| Aug 2025 | $442,489 |
| Aug 2026 | $446,754 |
Rent references
Two sources, never blended
| Source | Studio | 1 bed | 2 bed | 3 bed | 4 bed |
|---|---|---|---|---|---|
| HUD Small Area FMR, FY2026 | $1,190 | $1,270 | $1,490 | $1,890 | $2,150 |
| Zillow observed rent, Aug 2026 | not published for this ZIP | ||||
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: Baltimore-Columbia-Towson, MD MSA.
Property tax
- Effective rate
- 0.94%
- ZIP area, ACS
- At the typical price
- $4,204/yr
Median real estate taxes paid divided by median home value, Census ACS 2020 to 2024. Frederick County: 0.99%. Actual bills depend on the assessment, exemptions and any non-homestead rate.
Supply
- Permits per 1,000 households
- 10.3
- Frederick County, last 12 months
- National percentile
- 72th
- among US counties
1,074 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 |
|---|---|---|---|---|---|
| 21762Union Bridge | 4.8 mi | $327,000 | $1,590* | 5.8% | -$1,069 |
| 21776New Windsor | 4.9 mi | $487,000 | $1,540* | 3.8% | -$2,206 |
| 21757Keymar | 5.6 mi | $458,000 | $1,480* | 3.9% | -$2,052 |
| 21798Woodsboro | 5.7 mi | $507,000 | $1,260* | 3.0% | -$2,595 |
| 21793Walkersville | 8.8 mi | $466,000 | $2,000 | 5.1% | -$1,678 |
| 21778Rocky Ridge | 9.4 mi | $442,000 | $1,310* | 3.6% | -$2,095 |
| 21774New Market | 9.6 mi | $598,000 | $2,779 | 5.6% | -$1,894 |
| 21771Mount Airy | 9.7 mi | $634,000 | $2,220* | 4.2% | -$2,631 |
* 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 21791Questions
- Is 21791 good for rental property?
- On the typical home here, priced at $447,000 and renting for $1,490 a month (HUD Fair Market Rent, 2 bedroom, FY2026), the gross yield is 4.0% and the estimated cap rate is 1.1%. At a 7.78% investor rate with 25% down, estimated cash flow is -$1,986 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 21791?
- Zillow does not publish a rent index for 21791. HUD's FY2026 Small Area Fair Market Rent for a 2-bedroom here is $1,490, the 40th percentile of gross rents and the basis for Section 8 payment standards.
- What is the property tax rate in 21791?
- The effective property tax rate is about 0.94% of value (median taxes paid divided by median home value, Census ACS 2020 to 2024). On the typical $447,000 home that is about $4,204 a year. Your bill depends on the assessment and local exemptions.
- What interest rate makes a rental in 21791 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 21791?
- Over the 12 months to August 2026, the typical home value changed +1.0%.
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.
- 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.