Two California cities make the list of top three least affordable housing markets, a website that provides financial news and advice, recently released its list of the least affordable housing markets. This information was based on the median price of a home in each U.S. city and whether families earning the area's median income would be able to pay monthly mortgage payments using no more than 28 percent of their gross income. This "28 rule" is a standard that experts often take into consideration when conducting research for the housing industry.

"The fundamental [unaffordability] of these markets hasn't changed despite the fact that home prices are down and we're seeing incredibly low mortgage rates,"'s Mark Sante said of the data.

The top three least affordable housing markets are:

1. San Francisco, California – According to data, a median-priced home in this West Coast city is $552,600. Sante said that this is due to a number of factors, such as limited land in the Bay Area and the above average annual insurance premiums and property taxes that homeowners face.

2. New York City, New York – It shouldn't come as a huge surprise that The Big Apple nears the top of this list, as it's a historically expensive city to inhabit. With median property taxes at $7,183, that makes them the costliest of any U.S. city. A median-priced home in this East Coast metropolitan area is $377,600.

3. San Diego, California – Though many people want to live in this southern California hotspot, Sante said that there are limitations as to where new homes can be built in the city, making the home prices extremely high with a median cost of $379,100.

For people looking to buy property in these expensive U.S. cities, it's important to ensure that they can remain on top of their monthly mortgage payments. As such, lenders may want to invest in loan management software that can help borrowers stay financially responsible.