The hidden costs of owning a home in the 16 biggest cities in America

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When you become a homeowner, a mortgage isn't the only expense you're faced with.

The average homeowner in the US spends an additional $9,080 each year covering unexpected or forgotten costs, from insurance to taxes to maintenance, according to a new report from real estate-listing site Zillow.

"Determining how much a home will ultimately cost you each year and what you can afford is one of the most challenging aspects of homebuying, especially for first-time buyers," said Svenja Gudell, Zillow's chief economist.

Indeed, Zillow found in a previous report that nearly 40% of first-time buyers exceed their budget. It's easy to do. Although the standard measure of housing affordability is 30% or less of your pre-tax income, many homebuyers only plan in advance for their mortgage payment, forgetting about the extra expenses that are part of owning a home.

To give shoppers a more accurate idea of affordability, Zillow debuted a new feature earlier this year — the all-in monthly pricing tool — which considers all the monthly homeownership expenses typically omitted by a traditional mortgage calculator.

As part of its latest report, Zillow calculated the hidden costs of homeownership in the country's largest metro areas by population, factoring in property taxes, homeowners insurance, and utilities from Utility Score. They also included estimates for six of the most popular home maintenance-related projects from Thumbtack: carpet cleaning, yard work, gutter cleaning, HVAC maintenance, house cleaning, and pressure washing.

San Francisco homeowners shell out the most money of the metros Zillow analyzed, at just above $16,000 — not surprising considering the area's notoriously high home values and property taxes.

Below, check out how much homeowners spend on the unexpected — but often unavoidable — costs of owning a home in the 16 biggest US cities, from lowest to highest total cost.

The New York City metro area is a unique housing market and was excluded from Zillow's report.