Foreclosure filings jumped 79 percent last month in California, with some of the highest rates in local counties, according to a report released Monday by RealtyTrac.

Solano, San Joaquin and Contra Costa counties, where many first-time home buyers enter the housing market, were among 10 California counties with the highest levels of foreclosure activity in February.

Subprime loans were a factor in the higher foreclosure rates, observers say. Many of these loans, which are typically made to borrowers with low credit scores and low incomes, are resetting to much higher monthly payments after a two-year introductory rate.

Solano County ranked first, while San Joaquin County was ninth. Contra Costa County placed 10th, according to the monthly report from RealtyTrac, an online marketplace for foreclosure properties.

Alameda County ranked 14th while San Mateo County ranked 40th among the state's 58 counties.

Foreclosure filing activity can range from getting a default letter from a lender after not paying the mortgage for several months to having the lender take back the property and selling it.

California had 16,273 foreclosure filings in February, up 79 percent from a year ago. Almost 12,000 of the filings were default letters, the first step in the foreclosure process. Nationally, filings rose 12 percent from February 2006 to 130,786.

"Based on our numbers for the first two months of 2007, foreclosure activity is running at a rate that would project a 33 percent increase (nationally) over 2006," said James J. Saccacio, chief executive of RealtyTrac. "It appears that as subprime and FHA loans default at higher than anticipated rates and lenders tighten their underwriting standards, we're going to see a spike in the number of homeowners facing foreclosure."

While San Joaquin County is indeed seeing more foreclosures, the real spike has been in short sales, said Dave Konesky, a Realtor in the Tracy office of Prudential California Realty. A short sale, which requires lender approval, is when the homeowner sells the home for less than the mortgage in order to avoid foreclosure.

Konesky estimated the number of short sales last month were 10 times the number in February 2006.

"That's what I see happening, way more short sales than foreclosures," he said. "A lot of owners out there say, `Bring us an offer, I'm just on the cusp of foreclosure.'"

In February, Solano County had 589 homes in foreclosure, up from 227 a year ago. San Joaquin County had 329 homes in foreclose, compared with 314 a year ago.

Contra Costa County had 558 homes in foreclosure, up from 184 a year ago.

Solano County is definitely seeing an increase in foreclosures, said Jeff Dennis, president of the Solano Association of Realtors, which covers the southern part of Solano County.

"Foreclosures have been on the upswing," Dennis said. "We've seen a little uptick in Vallejo."

He thinks Solano County's lower housing costs in comparison to other parts of the Bay Area are a factor along with the increasing number of subprime borrowers who are seeing their monthly mortgage payment reset to higher payments.

"The affordability factor here is greater," he said. "You have people who are entry-level (home buyers) trying to get a leg up and into a home. ... Part of it is not understanding the nature of some these subprime and adjustable loans."

In Alameda County, 591 homes were in foreclosure in February, up from 254 a year ago. San Mateo County had 118 homes in foreclosure, compared with 77 a year ago.

In California, there was one foreclosure filing for every 751 households, which was 1.2 times the national average.

-Contact Eve Mitchell at (510) 208-6474 or emitchell@angnewspapers.com.