The percentage of Bay Area homeowners who are underwater -- which means their mortgage is higher than the home's value -- edged up from a year ago, as the housing market continues to struggle to get out of its very long slump.

Some 22.8 percent of single-family houses with mortgages were in negative-equity territory during the second quarter, up from 21.1 percent a year ago, said a report released Tuesday by Zillow, a real estate information website.

"Negative equity is growing because you still have foreclosures happening so the housing values are still declining," said Svenja Gudell, senior economist for Zillow. "As home values decline, negative equity will increase."

In Alameda County, 20.2 percent of homes were underwater, up from 17.7 percent, and in Solano County, 55.4 percent of homes were underwater, up from 51.5 percent

Some areas saw improvement. In Contra Costa County, 33.3 percent of homes were underwater, down from 36.6 percent a year ago. And 54.4 percent of homes in San Joaquin were underwater, down from 55.9 percent.

In Santa Clara County, 12 percent of homes were underwater, down from 12.8 percent a year ago. San Mateo County had 13.7 percent of homes with negative equity, up from 10.7 percent.

"Negative equity is still among us. We are still surrounded by it," said Jeff Pereyda, a broker-realtor with Tri-City Real Estate Brokers in Fremont. "Some are in negative equity and don't need to sell. Some are in negative equity and need to sell. We're seeing only the ones that need to sell."

Before the number of underwater homes can decline, homeowners need to increase their income so they can pay down their mortgage and equity line of credit, he said. Home values also have to rise.

Bay Area home values for the second quarter fell 6.2 percent from where they were a year ago, but rose 0.8 percent from the first quarter , said the Zillow report.

"We expect a bumpy road ahead. There will be many ups and downs in home values before this is over, and we continue to expect a true bottom in 2012, at the earliest. There are still hazards in the form of a full foreclosure pipeline, high negative equity and fluctuations in demand," Zillow Chief Economist Stan Humphries said in a statement.

Contact Eve Mitchell at 925-952-2690.

Underwater HOMES
Negative equity has worsened in the Bay Area, although some counties saw minor improvements. The chart lists the percent of single family houses in the region whose value was below the mortgage amount.
Region 2nd quarter 2011
2nd quarter 2010
Bay Area
Alameda County
Contra Costa County
San Mateo
Santa Clara
Solano County
San Joaquin County
22.8%
20.2
33.3
13.7
12
55.4
54.4

21.1%
17.7
36.6
10.7
12.8
51.5
55.9

Source: Zillow