Total monthly cost of ownership
Cost to Own a Home in St. Mary's County, Maryland
A $391,000 home here costs
$3,008per month, all in, with 20% down at today's 6.76% 30-year fixed rate. By the 28% rule that takes a household income of about $129,000 a year.
A standard mortgage calculator would have told you $2,031. The real number is $977 higher every month, 48% more than the payment most buyers budget for.
Compare with Charles County · Calvert County · Dorchester County · any county
Where every dollar goes
Only the first line is a mortgage payment. Change any assumption above and every figure below recalculates.
How St. Mary's County compares
St. Mary's County ranks 1,496th of 3,133 US counties by effective property tax rate, meaning property taxes here are lower than in 1,637 counties and higher than in 1,495. Within Maryland it ranks 19th of 24.
Paying the full bill when you don't have to?
Maryland runs property tax relief: homestead, senior, veteran and disability programs, and nearly all of it requires a filing homeowners never make. See what you can claim in Maryland. Buying instead? The state's down payment help is the program lenders forget to mention.
The numbers behind this page
| Measure | St. Mary's County | Source |
|---|---|---|
| Median home value | $390,900 | ACS B25077 |
| Median real estate taxes paid | $3,392 | ACS B25103 |
| Effective property tax rate | 0.868% | Derived |
| Median gross rent | $1,692 | ACS B25064 |
| Occupied housing units | 41,743 | ACS B25003 |
| Population | 114,372 | ACS B01003 |
| Residential electricity price | 21.84¢/kWh | EIA 5.6.A, June 2026 |
| 30-year fixed mortgage rate | 6.76% | Freddie Mac PMMS |
The risk behind the insurance bill
FEMA rates St. Mary's County's overall natural hazard risk Very Low among US counties. Expected annual losses to buildings, people and agriculture here run about $22.5 million a year, county-wide, across every building in it, not per household.
One thing to be clear about: the insurance figure above does not know about any of this. It applies your state's average premium rate to the county's median home value, because published premium data does not exist at county level. Two counties in the same state get the same rate here even when FEMA rates one of them Very High and the other Very Low. So in a high-risk county treat the insurance line as a floor, not an estimate, and get a real quote before you budget.
Ratings are FEMA's own, relative to all US counties. A high drought or heat rating also shows up in the climate figures for St. Mary's County.
Talk to someone who works this market
Every figure on this page is a county average. What your specific house costs, or what it would sell for, comes down to the street, the age of the roof and the condition of the systems. We will connect you with one licensed local agent who works St. Mary's County every week. Free, no obligation, and we never sell your details to a list.
I'm looking to buy in St. Mary's County I already own here and may sell
The weather behind that power bill
St. Mary's County runs an average high of 87.2°F in its hottest month and a low of 30.1°F in its coldest, with 46.32" of precipitation a year and 30% of it falling in a single three-month stretch. That climate is what sets the $203 electricity line above: 1,477 cooling degree days and 3,867 heating degree days a year.
See the full St. Mary's County climate breakdown , month by month temperatures, when the rainy season lands, snowfall, and what the heating and cooling actually cost.
Cities and towns in St. Mary's County
Each has its own median home value and its own effective tax rate, which can differ noticeably from the county average of 0.868%.
Neighbouring counties
Counties sharing a border with St. Mary's County. Crossing a state line can change the tax rate dramatically for an otherwise identical house.
Questions about owning here
What is the property tax rate in St. Mary's County?
The effective property tax rate in St. Mary's County, Maryland is 0.868% of home value per year. On the county's median home value of $390,900, that works out to about $3,392 annually, or $283 per month.
How much does it cost to own a home in St. Mary's County?
A $391,000 home in St. Mary's County, Maryland costs approximately $3,008 per month with 20% down at 6.76%. That breaks down as $2,031 principal and interest, $283 property tax, $98 insurance, $271 utilities and $326 set aside for maintenance.
Why is this higher than the payment my lender quoted?
Lender quotes usually show principal and interest only, and sometimes property tax and insurance. They almost never include electricity, water or a maintenance reserve. Here those add about $597 a month, which is why the real cost is 48% above the mortgage payment alone.
Is it cheaper to rent in St. Mary's County?
Median gross rent in St. Mary's County, Maryland is $1,692 per month, compared with $3,008 a month to own the median home all in. Renting is cheaper month to month, though rent does not build equity and is not fixed for 30 years.
How much is the electric bill in St. Mary's County?
Maryland residential electricity averages 21.84¢ per kWh. At the MD average household usage of 929 kWh per month, that is about $203. Actual bills vary considerably with house size, insulation and climate.
What salary do you need to buy a home in St. Mary's County?
Using the standard 28% rule, housing costs at no more than 28% of gross income, buying the median home in St. Mary's County, Maryland at today's rate takes a household income of roughly $129,000 a year. That covers the full $3,008 monthly cost, not just the mortgage payment.
Sources & methodology
- Median home value, real estate taxes paid, gross rent, occupied units and population, US Census Bureau, American Community Survey ACS 2023 5-Year, tables B25077, B25103, B25064, B25003, B01003.
- Effective property tax rate, median real estate taxes paid divided by median home value.
- Mortgage rate, Freddie Mac PMMS, updated weekly.
- Residential electricity price, US Energy Information Administration, Electric Power Monthly, Table 5.6.A.
- Homeowners insurance, NAIC average premium for Maryland ($1,238/yr), expressed as 0.3% of median home value and applied to the price above. A quote for your specific house will differ with roof age, claims history and coverage.
- Maintenance (1%/yr) and water and sewer ($68/mo) are modelled national estimates, not quoted figures. Every assumption is editable above.