Nowadays, it’s the mortgage that’s too damn high.

While it’s still cheaper to buy than rent in the 100 biggest cities in America, that may change very soon in some places, according to data released Wednesday from real estate site Trulia. The site looked at the monthly costs of renting and owning if you bought a place today, including rent/mortgage payments, maintenance, insurance and taxes, as well as one-time costs like security deposits and closing costs.

“The financial advantage of buying versus renting has decreased in all of the 100 biggest metros from the same time last year,” the report concluded. This, the researchers found, is “due to the fact that mortgage rates have increased slightly, rent price growth has slowed or hasn’t changed in 93 metros, and home values have increased in all 100 metros.”

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That said, you still get a lot of bang for your buck when you buy in some cities. In Baton Rouge, for example, it’s 50% cheaper to buy than to rent, and in Philadelphia, New Orleans and Columbia S.C. it’s roughly 48% cheaper. Seven of the top 10 spots where buying is still much cheaper than renting are in the South, including West Palm Beach, Birmingham and Charleston S.C.

But in some cities buying is barely a deal anymore, thanks in part to rapidly escalating home prices in the areas. Indeed, for the first time in four years, the margin between renting and buying in San Jose (median rent: $3500), San Francisco ($4100), and Honolulu ($2500) dipped into the single digits.

3 cities where buying outweighs renting by the slimmest margins

Metro area Percent cheaper to buy than to rent, Spring 2017
San Jose, Calif. 3.5% cheaper to buy than to rent
San Francisco 8%
Honolulu 9.9%

To tip the scales towards renting in San Jose, mortgage rates would only need to inch up 0.6 percentage points to 4.7%. And in San Francisco and Honolulu, a 1 percentage point and 1.2 percentage point uptick, respectively, would do it.

And experts say mortgage rates very well may tick up this year. “While rates took a dive last week, it’s not crazy to think that rates will rise this year,” a spokesperson for Trulia tells Moneyish, who thinks a slow and steady rise is most likely. “The Fed has indicated that they intend to raise rates again.” And, in general, rates are climbing: In Freddie Mac’s weekly mortgage rate report, the rates for 30-year fixed rate loans hit 4.02%, up from 3.58% a year ago.

Of course, there are still good reasons to buy a home even if renting is somewhat cheaper each month. And there are more factors to consider when buying than just costs of renting as compared to buying. This helpful calculator can help you figure out when it makes more sense for you to rent or buy.