Record numbers of Sonoma County homeowners are seeing property taxes fall, softening the blow from plummeting values as the housing downturn takes an ever wider toll.

After reducing property tax bills for about 25,000 homeowners last year, the county could add another 15,000 this year. That two-year total would more than double the county's previous high, which occurred during the last housing slump in the mid-1990s, said Bill Rousseau, the county's deputy chief assessor.

It's a staggering total: Nearly four of every 10 houses in the county, he said.

"This is busier than we've ever been," Rousseau said. "We need to see the market bottom out. Until it does that we're going to be in a reduction mode for a while."

Property tax cuts could also further crimp budgets of the county's financially strapped schools, governments and special districts. Little relief is in sight.

Home price declines are showing few signs of bottoming out. Economists who track the county market have said the falloff could flatten during the second half of this year.

The county assessor's staff is expanding its re-assessments to properties purchased during the early years of this decade after initially concentrating on sales around the height of the housing boom in 2005.

Steven James and Judy O'Brien bought their Windsor home in February 2005 for $670,000. While the couple recognized the county's housing boom would eventually end, they didn't think the subsequent decline would be so steep -- the county's median home price is down nearly 50 percent from the market's high.

"I thought there's no way that would happen. We're staring at that in the face right now," James said.

The couple requested a reassessment in 2008 after deciding against it a year earlier. The county lowered the value of the couple's 1,640-square-foot, three-bedroom home to $469,000. Easing the pain was the $2,600 property tax reduction.

"It was wonderful," James said. "Spending $8,000 in taxes on a devaluing asset would have been a little hard to swallow."

Not all homeowners are satisfied, complaining the county doesn't lower values enough on their properties.

The county has cut Berry Pevey's property taxes by $2,700. "It's not bad," Pevey said, but he believes it should be better.

County assessor's staff has lowered the value of Pevey's home each of the past two years, from the $610,000 purchase price to $400,000 now. He contends the Rohnert Park residence is worth $350,000.

"I think they're trying to squeeze every penny they can. I think they're being unrealistic and deliberately so," Pevey said. "We've done that two years in a row and we've gone through the same troublesome process."

Not giving up, Pevey has filed a formal appeal of the reassessment.

Rousseau said the county assessor's staff cooperates with homeowners and has initiated most of the property value reassessments granted the past two years.

"We did the best job we could," he said. "If the taxpayer has better information, we will always take a second look. They may have found better comparable sales or something about the property was unique that we needed to reconsider."

The assessor's staff workload has tripled as it works through a mounting volume of homes with falling values. This is in addition to its typical work adding new homes to the property tax rolls and reassessing existing homes to reflect purchases.

Under state law, the county can temporarily reduce the tax amount when a property is valued at less than its assessed value on the county rolls. The valuation is limited to sales of homes with similar features and comparable locations between Jan. 1 and March 30 of the same year, Rousseau said.

"That's where most of the misunderstandings are," he said.

A particularly contentious issue is when the county sets a home's value for tax purposes above the price paid, ruling the sale does not reflect the property's actual value. That is occurring more often with banks and lenders slashing prices on foreclosed homes in a market crowded with distressed properties.

Homeowners can contest assessments through a formal process with the county's assessment appeal board. Those requests must be filed between July 2 and Nov. 30 each year.

Informal appeals for reassessments can be made to the county assessor throughout the year. Those decisions may not be challenged.

Once adjusted downward, the county is required by state law to review those assessments annually to account for any further change in value -- either up or down. The annual reviews will occur until the property has reached the value -- plus inflation -- it had when it initially was reassessed downward.

More real estate agents and mortgage brokers are helping clients seek reassessments. Some charge fees. Others don't, using it as a marketing tool.

Real estate agent Mandy Galea has helped about 150 homeowners gain lower property values. She doesn't charge, saying the process is simple because the informal appeal requires only a one-page form and three comparable home sales.

"I was really impressed with how quick the county moved. It shows the county's not in denial," Galea said. "You might as well take advantage of that because when the values go up, you know they're going to hit us."