According to recent data, the cost of renting a home is rising across the country. Some of the gains can be attributed to the rise in home values over the past couple of years, and some can be the result of the reluctance or inability of people to buy homes.

However, the national rise in rent doesn't tell the whole story. There is tremendous diversity between real estate markets all over the U.S., and just because landlords are doing well in one area doesn't mean they're doing well everywhere. In fact, there are several states where it's getting more expensive to buy a rental property, but rent isn't rising nearly as quickly.

For example, in Maryland, home values have risen by a healthy 5% over the past year. However, rental prices have remained flat, meaning that it costs more to buy a house while landlords aren't making any more money.

And if home prices are rising faster than the cost of rent, it may not make good financial sense to buy a home to rent out. Here are the five places in the U.S. whose home values are soaring, but rent prices just aren't keeping up.

5. Arkansas

Source: Wikipedia.

Arkansas' home values have made nice gains recently, just like most of the United States. The average home in Arkansas is worth about 7% more than it was at this time last year. However, unlike much of the country, the rental market in Arkansas has barely budged, with the cost of rent increasing by less than 1% over the past year.

Still, there may be home for would-be landlords in Arkansas. According to the most recent data, home prices are beginning to decline in Arkansas, with the average sale price dropping by 2% in July alone.

4. California

Source: Wikipedia.

California's real estate market has been on a tear recently. In fact, California's home values have grown by almost 13% over the past year and are projected to increase by another 9% over the next year, the highest projected increase in the nation. Plus, according to Zillow's "market health" data, five of the six healthiest metropolitan real estate markets in the U.S. are located in California.

And, while rents are on the rise in California (up more than 5% in the past year), it's nothing compared with the massive gains in home values. It's just getting very expensive to be a property owner, and it looks like it could get even pricier.

3. Hawaii

Want to move to Hawaii? You may be better off renting, as it looks like home prices are catching up to the high cost of renting. Over the past year, rental prices in Hawaii have risen by less than 2% while home values have grown by nearly 10%. Hawaii is and always has been an extremely expensive rental market, so it's entirely possible that prices just don't have much more room to the upside.

And landlords in Hawaii may have certain expenses to worry about that aren't a factor in other states, such as flood insurance, which is increasing at a rapid rate because of the scaling back of government subsidies.

2. Washington, D.C.

Source: Wikipedia.

The District of Columbia has seen some of the sharpest home value gains in the nation, with the average home worth over 10% more than it was a year ago. When combined with the average rent increase of just 1.3%, becoming a landlord in the nation's capital has become much more costly over the past year.

Some of the lack of rental increases could be due to the increased supply of rentals on the market. According to DC Insider, there were nearly 14,000 rental listings during the month of August, an increase over 30% since the beginning of the year.

1. Nevada

Source: Wikipedia.

People who bought homes in Nevada since the recession hit are certainly happy. Home values in the state's major markets are up more than 60% since bottoming in early 2012, and are up nearly 18% in the past year alone.

However, rent hasn't kept up. Despite the impressive gains in home values, the cost of renting in Nevada has barely budged, up less than 2% year over year. Although Nevada homes are still much cheaper than their pre-crisis peak, it looks like the days of incredible deals on investment properties may be over.

Of course, these are just general trends and statistics, and with the correct due diligence, it is possible to find excellent deals on investment properties anywhere. It's just not as easy to do in these places as it is in others.

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