Home values are expected to rise by more than $40 billion in the greater Washington area in 2012, part of the largest nationwide increase in values since 2005, according to Zillow Real Estate Market Reports.

Collective home values in the Washington, D.C., market are projected to rise by $40.5 billion in 2012, or 4.9 percent, after gaining nearly $22 billion the year before, to $872.2 billion.

In Baltimore, home value gains are expected to total $4.3 billion this year after a drop of more than $18 billion in 2011.

“The housing market really turned a corner in 2012, as historic affordability and sustained investor interest helped keep demand at a boil,” said Stan Humphries, Zillow chief economist. “As home values rise, and more homeowners are freed from negative equity, we can expect a continued slow transition to a more normal housing environment.”

The nationwide gain of an estimated 6 percent this year is the first increase since 2006, as values have climbed more than $1.3 trillion to $23.7 trillion. More than 75 percent of the 177 metro areas that were analyzed experienced cumulative home value gains in 2012. Of the 30 largest metros, only Philadelphia failed to record an annual gain.