Although interest rates for 30-year fixed-rate mortgages are expected to reach nearly 4% during the second half of this year, rates would have to be nearly 7% before a U.S. median-priced home would become unaffordable for a median-income family.

According to Freddie Mac's June 2013 U.S. Economic and Housing Market Outlook, this is true for most parts of the country, though some metro areas—such as Los Angeles and New York City—already have housing costs that are out of reach for many families. A map of the country created by Freddie Mac shows that most large metropolitan areas of Texas remain affordable even at 6%-7% interest rates.

Interest rates for 30-year fixed-rate mortgages have increased .5 percentage points over the past month or so, and Freddie Mac predicts a sharp decline in refinancing volume later this year as rates gradually increase.