America's least affordable housing markets all cost big bucks because lots of people want to live there, but oceans or other natural barriers leave little available real estate for additional homes.
"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," says Mike Sante of Interest.com, which recently compared median incomes and home prices in America' 25 largest cities.
Interest.com found that families who make local median incomes in 11 of the 25 areas studied don't make enough to qualify for the mortgages they'd need to buy median-priced homes there.
Sante says America's least affordable cities all combine strong consumer demand with low housing supply due to a lack of open space for added construction.
"Consider San Diego, which is bounded on the west by the Pacific Ocean, on the south by Mexico and on the north by some very, very large military bases," he says. "The only place for San Diego to expand is eastward into the desert -- and that puts a tremendous restriction on development."
By contrast, Sante says that cities Interest.com found have high affordability typically have lots of available land.
"Without getting into a discussion about urban sprawl, the fact is that when can you expand in all directions and have lots of land to build on, that helps hold down local median home prices," he says.
Here's a look at the five cities Interest.com found are the least affordable places for U.S. homebuyers.
The list of housing markets was compiled by calculating how much you'd pay each month for a median-priced home in each city, assuming you put 20 percent down and got a 30-year fixed mortgage that charged the local average interest rate.
Interest.com added median annual local property taxes and homeowners' insurance premiums and looked at whether a family earning a given city's median household income could meet the "28 percent rule." That standard, which lenders have historically used when deciding whether to OK a mortgage, looks at whether a borrower can pay all monthly housing costs using no more than 28 percent of gross income.
All median single-family-home prices listed are as of the second quarter, while 30-year fixed-mortgage rates are as of Sept. 19. Median annual household incomes and property taxes are as of 2011, while average annual homeowners' insurance premiums are as of 2009.
"Above-average" and "below-average" figures refer to the average of all 25 cities analyzed -- $50,502 for incomes, $2,331 for property taxes and $880 for insurance premiums. "Average home prices," though, refer to the $229,516 median found in a larger pool of locations that the National Association of Realtors tracks.
5. Los Angeles
The City of Angels is a real devil when it comes to housing affordability.
Interest.com found that while Los Angeles households enjoy above-average median incomes ($56,653), the metro area's high median home prices ($296,800) and property taxes ($3,985) eat all of that up and more. La-La Land's residents also pay a slightly above-average $922 in median homeowners' insurance premiums.
Add it all up and a typical Los Angeles family makes 12.5 percent too little to qualify for a mortgage on a median-priced L.A. home.
"Los Angeles just has much-higher-than-average home prices," Sante says. "Even though they have slightly higher median incomes, it's not enough to make up for that."
The U.S. housing bust has left Miami's median home prices at a below-average $206,700, but the typical family there also makes a below-average $45,407 income. That trails only Tampa as the nation's lowest median income for any major city.
"Miami's property values have fallen, but they haven't fallen enough to offset the fact there are a lot of 'low-middle-income' households in town," Sante says.
Miami also has above-average median property taxes ($2,600) and homeowners' insurance ($1,460 a year, due to high hurricane risks).
All told, Interest.com found that Miami households make a median income that's 12.6 percent below what they'd need to get a mortgage for median-priced local there.
3. San Diego
"San Diego is a place where lots of people want to move, but the city is very constricted in terms of where it can build," Sante says. "As a result, it has extremely [high] home prices."
Interest.com found that a median San Diego-area house costs $379,100 -- trailing only San Francisco as the nation's priciest housing.
Above-average median property taxes ($3,384) and homeowners' insurance premiums ($922) only add to affordability woes.
True, San Diego does have an above-average median household income ($59,477). But Sante says that's "not nearly enough to make up for the high property taxes and the way-way-way-above-median home prices."
The bottom line: The typical San Diego family makes 26 percent too little to get a mortgage on a median-priced local home.
2. New York
The Big Apple offers consumers little in the way of housing affordability.
New York's $7,183 median property taxes are No. 1 among major U.S. cities, while Gotham's $377,600 median home price trails only San Francisco's as the nation's highest.
New Yorkers also pay a higher-than-average $1,021 a year in median homeowners' insurance premiums.
As a result, Interest.com found that even though New York families enjoy an above-average $62,322 median household income, that's still 29.7 percent below what's needed to qualify for a loan on a median-priced local home.
1. San Francisco
If you're going to San Francisco, be sure to wear some flowers in your hair -- and put lots of money in your wallet.
That's because Interest.com found that the City by the Bay has the absolutely worst housing affordability of any major U.S. metro area.
San Francisco's $71,975 median household income trails only Washington's as the highest among major cities, but it's still 32.8 percent too low to allow a typical family to qualify for a mortgage on a median-priced home.
Sante says that San Francisco is unaffordable mostly because it has the nation's most-expensive properties: $552,600 for a median-priced home.
"Again, it's all due to limited land," he says. "You're hemmed in by the Pacific Ocean and bay, and concerns about earthquakes limit the density of the housing that you can develop."
Interest.com also found that the typical San Francisco homeowner faces an above-average $922 in annual insurance premiums, plus a median $4,991 in property taxes -- second only to New York as the nation's steepest annual bill.
More on TheStreet.com
What's Your Savings Resolution for 2013?
5 Best Car Redesigns for 2013
5 Most Infamous Cars Of 2012