Vashon’s property values fell 8.4 percent this year, while countywide they’ve dropped around 14 percent, the first countywide decline in property values in nearly 20 years, according to County Assessor Lynn Gering.

Pockets of the county have stayed flat or even fallen over the past two decades, she said. But the county’s overall decline in property values is the first it has recorded since the early 1990s.

“This is somewhat unprecedented,” Gering said in an interview Friday.

The declines varied across the county. In Normandy Park, for instance, assessed values fell 21 percent decline; Mercer Island’s values fell 17.4 percent; Fauntleroy saw an 18 percent plunge.

The fact that Vashon’s values declined less than other nearby residential areas suggests that either properties on the Island were already assessed lower than those elsewhere or “that some pockets on Vashon held their values better,” Gering said. Some of the areas in the county with the biggest drops, she added, were those that have seen a lot of new construction in recent months.

And even on Vashon, Gering said, there were significant differences. Waterfront homes and those larger than 1,500 square feet “held their values somewhat,” she said, while other properties saw a 12 to 13 percent decline in assessed value.

“We use the same methodology countywide,” she added. “The real estate market is just different than it’s been before.”

The 2009 values, which are being mailed out to Islanders this week, are used to determine residents’ 2010 tax bill, which will be mailed out in February. A lower assessment, however, doesn’t necessarily mean a homeowner’s taxes will go down. Some taxing districts — such as the Vashon Island School District — garner a set amount of money, according to the levies or bonds voters have passed. Once such measures are approved, the levy rate (the amount charged per $1,000 of value) simply goes up if values drop.

“The budgets will be collected regardless. That’s what most taxpayers don’t understand,” Gering said.

But some of the so-called junior taxing districts — such as the Vashon Park District and Vashon Island Fire & Rescue — ask voters to approve rate-based levies. Rather than seeking a fixed-dollar amount to be collected, these measures ask voters to approve a levy rate. The Vashon Park District, for instance, will ask voters in November to approve a levy of 50-cents per $1,000 of assessed value.

With the drop in values, the park district will likely bring in about $100,000 less than it had anticipated, said Wendy Braicks, the park district’s executive director. The district had hoped to garner $1.4 million with a 50-cents levy rate, she said. If voters pass the levy this fall, the decline in values means the district will likely collect $1.3 million.

“We haven’t begun to create our budget. We’ll certainly make it work,” Braicks said.

Real estate agents, meanwhile said they believe Vashon’s market has declined more precipitously than the new values out of the Assessor’s Office suggest.

“We’ve seen people have to drop their prices 20 percent to get a sale,” said Denise Katz, an agent with Vashon’s Windermere office.

Ken Zaglin, who owns the John L. Scott office on the Island, agreed, adding that the county’s numbers often lag behind the actual market.

“The market has had a tremendous drop in value. So that 8 percent drop doesn’t reflect that,” he said.

Because values affect taxes, some Islanders will likely be upset that their assessments did not fall more, he added.

“You’re paying taxes on that assessment. So paying more than your home is actually worth is painful,” he said.