Shock and disbelief greeted Colin Heydt when he opened DeKalb County’s tax assessment notice on his Candler Park home. Across the county in Stone Mountain, Jan Dunaway had the same reaction.

Unlike residents in Gwinnett or Fulton, who have flooded their counties with appeals for lower assessments, many DeKalb property owners insist their home values are far too low.

In order to maintain services, such as police and libraries, residents say they’d prefer to see higher home assessments -- which means higher taxes regardless of rate -- instead of what they think are unrealistically low assessments. The drop in home values has the county thinking of raising taxes up to 4.5 mills, which would increase taxes about $93 a year on the average home, which this year is assessed at $155,700.

“If you are going to take one of the better off neighborhoods and give people 60 percent off their taxes for no apparent reason, something is dramatically wrong,” Heydt, a philosophy professor whose four-bedroom home, with a separate carriage house, plunged 57 percent from an assessment of $440,700 to $189,960.

“I’d be happy to pay more in taxes than what I’m currently scheduled to, because it’s only fair,” Heydt added. “Without an adjustment, you’re talking about the potential for millions of dollars in lost revenue.”

DeKalb’s chief appraiser Calvin Hicks couldn’t believe his ears when calls complaining about values too low started coming in. He defended the county’s assessments but admits the numbers could be off in some areas, including the Candler Park neighborhood.

“It’s as accurate as we can make it, given the confines we’re working with,” Hicks said. “Really, it’s been an unusual year.”

He attributes the plunging values mostly to a new state law that requires distressed sales be included when calculating the market value. Because DeKalb has the third highest number of foreclosures in the state — with 7,645 foreclosures announced between January and May — those sales are pushing down values countywide.

The resulting 13 percent drop in value, down to $20.8 billion, is the worst among metro Atlanta counties. The drop is felt more acutely by homeowners because DeKalb is 65 percent residential and lacks the industrial and commercial properties that have helped prop up values in neighboring Fulton and Gwinnett counties.

Gwinnett, for instance, saw a decline of about 9 percent to its digest while Cobb county’s values fell about 7 percent. Reports show Fulton County may be estimating a decrease of about 8 percent, though official figures were not available.

Compounding the problem was the loss of six experienced appraisers last year to better paying jobs in Fulton, Hicks said. Those workers, who have not been replaced, had the institutional knowledge to question whether a 60 or 70 percent drop really reflected the neighborhoods.

“We’re human,” Hicks said. “If we made an error, we will review that and correct it.”

So far, his office has agreed to re-examine five neighborhoods where property owners think the values are depressed, including parts of Candler Park, areas in and around Avondale Estates and North Druid Hills. If more calls come in, Hicks said his office will review those complaints, too.

Those reviews won’t be done before next week, though, when the county commission is expected to join other metro counties that have raised their tax rates to offset the losses the sour economy has had on property values.

A new state law required every property receive its assessed value this year. The law also makes it easier to appeal that assessment, with many counties offering an online link from their appraiser’s office that will generate a review from the local Board of Equalization.

So far, commissioners have tried to battle the shrinking property tax base with budget cuts. Any movement to boost values would seem to help keep any increase as low as possible.

“I’m concerned because the projections we have on revenue may not include any glitches, so we’ve got to go back and look at these assessments,” said Commissioner Kathie Gannon. “This doesn’t even look like it’s following a formula.”

Commissioner Lee May, who heads the commission’s budget committee, said he believes Hicks’ office is getting a grip on any problems.

“We had a huge increase in previous years and now it’s falling, and it’s complicated to provide an accurate assessment with all of that movement,” May said.

In the meantime, stories abound of neighborhoods where some property values plunged while others barely saw a change.

For instance, homes in Rammel Oaks, a newer subdivision outside of Avondale Estates, held their exact value from 2010, according to county tax records. Undeveloped lots dropped between 55 and 70 percent, including one now valued at $22,320 despite selling in foreclosure in November for $216,000.

In the Fells Ridge subdivision where Dunaway lives, most values shriveled 60 percent. A nurse, Dunaway was stunned to see that her three-bedroom, two-bath home is assessed at just $44,500.

But what had her scratching her head was learning that values of 16 of the 80 homes in the subdivision dipped just 27 percent.

“They’re going to make us poor and charge us more,” Dunaway said of the assessments. “We’re going to pay our taxes one way or another, but for goodness’ sake, don’t raise the millage rates unless that’s what you need to do.”