It Didn't Sell at $839,000, So the Owner Rented It Out. Here's the Math

In July 2025, a 3 bedroom, 1,316 square foot townhouse in San Marcos (92078) went on the market at $839,000. After 250 days it came off the market unsold. In January 2026, with the sale listing still up, the owner listed it for rent as well, and a tenant signed at $3,500 a month after 23 days.

This owner is one of 128 San Diego homeowners we tracked in the last 8 months who couldn't sell and rented instead, the people Zillow calls accidental landlords. Here is that choice in public numbers.

What renting it pays

At our default costs, the $3,500 rent nets about $710 a month, or $8,516 a year. Property tax on the county's $590,706 taxable value is about $591 a month, the HOA is $454, insurance is $244 and upkeep is $697. Vacancy, management and a reserve for repairs take another $805.

What selling would have paid

Four townhouses with the same floor plan on the same street sold for $800,000 to $840,000 between October 2025 and May 2026, a median of $836,000. A sale at that price would have netted about $785,840 after 6% in selling costs.

Keep or sell

The rent's $8,516 a year is about 1.1% on that $785,840. A 10 year Treasury paid 5.22% on October 8, 2026, about $41,021 a year on the same money. For keeping to come out ahead, the home has to gain about 3.9% in value every year.

Keeping has advantages the table doesn't show. The owner's property tax is figured on $590,706, while a buyer at $836,000 would pay about $2,944 more a year. Selling can also trigger capital gains tax, which a CPA can figure for a specific owner.

If there is still a mortgage

Working the county's value back to the 2016 deed with the Prop 13 caps suggests a price of about $489,208. With 20% down at 2016's 3.65% average rate, about $302,951 would still be owed. With that loan, the owner would pay in about $2,554 a year after interest, while a sale would pay it off and leave about $482,889, worth $25,207 a year in Treasuries. Keeping would need about 3.3% a year in appreciation instead of 3.9%, since a loan cheaper than Treasuries helps the owner who keeps.

What it means if you own one

Most accidental landlords are not cashflow investors. They are owners waiting out a slow market, and that works as long as the home keeps gaining value. Our keep or sell tool runs the same math with your loan, your tax bill and your rent, and you can see how San Marcos compares as a rental market.

Figures use our default assumptions: property tax at 1.2% of the county's taxable value, insurance at 0.35% and upkeep at 1% of the home's value a year, 8% vacancy, 10% management and 5% of rent for repairs. The real mortgage isn't public, so the loan above is an illustration.