You learn a lot about a house once you live in it for a few months. You hear some creaky sounds; you meet some odd neighbors. And your first bills start to arrive. It turns out that the monthly costs of owning a home can be a lot more complicated than the original math you did months ago. Sure, you took into account mortgage payments, property taxes, and utilities. But new costs in the form of local taxes, insurance rate hikes, or even some other surprise fees can pop up—often for reasons you never saw coming. Here are nine examples of new costs U.S. homeowners are facing—and how you can be sure to factor them into your future home budget.