Some of metro Atlanta’s biggest counties mailed hundreds of thousands of property tax assessments this week, and they’re bracing for a wave of appeals despite lowered values and bills for many homeowners.

Under a new state law that took effect Jan. 1, notices this year must go to all property owners even if values stay the same. The law, passed in 2010, aimed to simplify the appeals process for homeowners following complaints that values remained fixed far above market values in the wake of the real estate bust.

Fulton County sent out 332,835 assessment notices on Thursday and Friday, Chief Appraiser Burt Manning said. More than half -- 173,960 -- showed values dropping, and close to half -- 155,994 -- had values staying the same.

Cobb County mailed about 230,000 notices on Friday, 90,000 of them showing reductions, officials said. DeKalb County will send 235,000 notices around the third week of May, Chief Appraiser Calvin Hicks said, and he hasn’t yet tabulated how many will show decreases.

Gwinnett, which mailed out 256,000 residential notices on April 15, may provide a preview of what to expect. About 100,000 of the notices reported decreases, but Chief Appraiser Steve Pruitt said he’s already had 5,000 appeals filed, more than double the number at this time last year.

He expects an avalanche in the two weeks before the end of the 45-day appeal deadline.

“Everything’s different this year,” Pruitt said. “Fulton County, in my opinion, should be prepared for about twice what they’re regularly expecting.”

In Fulton, the state’s largest county and a cradle of taxpayer unrest, the decreases might not be enough for many homeowners. With everyone getting a letter, many taxpayers who might have let appealing slip their minds in years past will be spurred into action, county officials predict.

A notice also gives everyone the right to appeal. In years past, if values stayed the same and no notice was sent, a homeowner lost that option if they didn’t file a return -- an official statement contesting the county’s assigned value -- before April 1.

Still more appeals may be filed for strategic reasons. Through an older law, anyone who appeals and takes their case to the Board of Equalization, or anyone who settles in writing with the Board of Assessors, can get their value locked in until 2014, so long as they don’t make major improvements or contest their value again.

That’s what Sandy Springs homeowner Ashley Jones plans to do. Last year, he was caught off guard after he bought his two-story stucco home with an indoor pool for $325,000 in a 2009 short sale, only to find out the county kept the value at $408,400. Busy with a new job after being out of work for six months, he missed the deadline to file a return.

This year he’s ready, having filed a return in January declaring that the house is worth what he paid for it. If granted, the value would lower his $5,150 in county and city tax bills by more than $1,000.

“One of the things I was worried about is, they may give it to me this year, but then come back and raise it next year,” Jones said. “I’ll be appealing no matter what the values are.”

Georgia Property Taxpayers Committee president R.J. Morris recommends the tactic to any property owner looking to freeze their value. The new law requiring annual assessment notices also requires that any house bought in 2010 be assessed at no more than the sale price in 2011. But a county could always raise the value in 2012, Morris said.

“This is the year for homeowners to protect themselves,” Morris said.

The new law, Senate Bill 346, was sponsored by Senate Majority Leader Chip Rogers, R-Woodstock. It followed an Atlanta Journal-Constitution investigation showing that thousands of metro-area properties were overvalued for tax purposes. The newspaper concluded that county appraisers either ignored, or failed to keep pace with, the real estate market collapse. Follow-up investigations published last year found some counties have made improvements, but still lag behind ever-plummeting values.

Manning said he can't predict how many appeals Fulton residents will file this year.

“If we get 10,000 a week, we’ll handle it,” Manning said. “If it’s 1,000 a week, we’ll be smiling.”