Trying to decide whether to rent a home or buy one? Although many people assume that buying a home--if you can--is always smarter than renting one, there are many good reasons why renting can be smarter than buying. Will paying a mortgage be a financial stretch for you? Would you have a hard time handling the kind of unexpected expenses that houses often generate? Are you too busy, or travel too frequently, to look after a house and make sure it's well maintained? Do you anticipate needing to move again within the next five years? If you answered yes to any of these questions, renting might well be the better financial bet.

But even if none of these reasons apply and buying sounds like it might be the right choice, there's one other big question to ask: Will you be buying into a real estate bubble? If housing prices in your hometown are about to plummet, then you're much better off waiting a year or two or more, investing your down payment so that it grows, and then buying later on when it's more of a buyer's market and you can get a better home for less.

Of course, no one can dependably predict what will happen in the housing market or any other market. But there are certain economic indicators that do suggest that a city's housing is overpriced and may be about to take a downturn. Luckily, the folks at the personal finance site GOBankingRates have analyzed three of those factors: percentage of houses "underwater" (i.e., worth less than their mortgages); vacancy rates; and delinquency rates on underwater mortgages, for 54 major American cities.

It makes a lot of sense to look at these metrics. High vacancy rates naturally drive home prices down, and a large proportion of underwater mortgages may mean some homeowners are desperate to sell. And when people stop paying the mortgage on their underwater homes, either because they don't want to or can't, those homes stand a greater chance of winding up in foreclosure and being sold at bargain-basement prices. Which drags down the prices of all homes.

You can find the full list here of cities in danger of a housing downturn. Here are some where the danger is most acute:

1. Newark

This city across the river from New York is the largest municipality in New Jersey and home to one of the New York metro area's three major airports. But at just over 20 percent, it also has the nation's highest delinquency rate on underwater mortgages. And more than 29 percent of the city's homes are underwater.

2. Chicago

The Windy City, like many other non-Silicon Valley towns, has laid claim to being the next tech entrepreneurship hub. But Chicago is the rare urban area whose population is shrinking instead of growing. That's a bad sign, because it suggests people aren't finding attractive opportunities there, and also because the more people leave, the more vacancies there are. Consider that Chicago has more than 71,000 homes that are underwater on their mortgages, and you can see that a housing price drop may be coming.

3. Hartford

Connecticut is a famously wealthy state, where prep-school kids grow up. But Hartford is that rich state's poorest city. The city only has 3,608 homes that are underwater on their mortgages, but they constitute a surprising 43 percent of homes overall, according to GOBankingRates. To add more fear factor, delinquency rates there are high.

4. Jacksonville

This city in Northern Florida has nearly 40 percent of its homes underwater on their mortgages, perhaps because the state in general suffered from inflated housing prices in the run-up to the 2008 crash. Still, it's worth noting that a couple of years ago, Jacksonville was number 9 in the top ten list of cities for venture capital when population size is taken into account. Which means if you want to launch or work in a startup, Jacksonville might be a pretty good place to live. Just be sure you're ready to stay a long while before you buy a home.

5. Baltimore

Baltimore has an unusual combination of high cost of living and relatively low rent, GOBankingRates research found. That can signal trouble for the housing market, because people are less tempted to buy when rents are low, and because everything else is so expensive, many couldn't afford a down payment even if they wanted to buy. There are more than 20,000 homes in Baltimore that are underwater on their mortgages, 22.3 percent of all homes.

6. Cleveland

I visited this town for the first time on a trip across the country, and was completely charmed by the beauty of the city. But lovely as it is, 31 percent of Cleveland homes are underwater on their mortgages. That's just under 14,000 homes, and it could spell trouble for Cleveland home prices in the next few years. Still, the city is home to a bevy of fast-growing companies. So its long-term prospects might be better.

7. Las Vegas

Vegas was infamously overpriced and overbuilt before the housing bubble burst in 2008, and it crashed hard. A few years later, Zappo's CEO Tony Hsieh moved his company there and poured $350 million of his own money (from sale of the company to Amazon) into creating a lively downtown community and startup hub there. But that effort has yielded limited results so far. 

Meantime, Las Vegas has more than 33,000 homes that are underwater on their mortgages, although they make up less than 17 percent of the total. And delinquencies on payments for those underwater mortgages are relatively high as well. Which means it's probably smart to rent and wait out the market if you're going to live in Sin City.

8. Birmingham

In this Southern city, the housing slump is already underway, with prices down more than 13 percent from this time last year, according to GOBankingRates research. Is there more downward momentum to come? Maybe, because Birmingham has the highest rental vacancy rate of all the cities GOBankingRates studied. Higher rental vacancies mean landlords may have to lower their rents or offer incentives to bring tenants in, likely making it considerably more attractive to rent than to buy.