TAMPA - Plummeting property values will mean lower tax bills this year for many Hillsborough County homeowners but more pain for cash-strapped local governments.

Figures released Wednesday showed that taxable property values fell 13 percent this year, a decrease county property appraisers called unprecedented. It was the second year in a row property values dropped after years of steady, often double-digit increases.

"We had a 5 percent cut last year, which was fairly monumental," said Tim Wilmath, director of valuation for the property appraiser's office. "This dwarfs that."

As of Jan. 1, taxable property values in the county totaled about $73 billion, down from $83.7 billion the previous year. The drop confirmed the fears of many local government officials that they must cut budgets and reduce services.

The figures are based on transactions in 2008 and include homesteaded and non-homesteaded residential property, commercial property and new construction. Taxable values are the basis for most local governments; lower tax bases mean either less money coming in from property taxes, or higher tax rates.

Factors pulling property values down included a high number of foreclosures, poor home sales, little new construction, and higher vacancy and lower rental rates in commercial properties.

The decline will be a blessing for some homeowners who will see their market values drop below their Save Our Homes cap on assessed value, lowering their property tax bill. Those most likely to benefit bought their homes at the height of the real estate boom in the first six years of this decade and had their property appraised at those higher values.

"They got hit the hardest, and they should benefit the greatest," said Warren Weathers, chief deputy property appraiser.

The amount of money saved depends on when the home was purchased, how much it cost and its assessed value.

Residents who have owned their homes for a decade or more will probably not see a tax break because their assessed values have risen slowly under the Save Our Homes cap.

The decline in property values means local governments and other taxing authorities will have about $200 million less to operate on this year than last. The amount of money each government will lose won't be calculated until Friday, Weathers said.

Hillsborough County Administrator Pat Bean said the county has been basing next year's budget on a 13 percent drop in property values. The county is projecting a revenue loss of about $110 million because of the decline in valuation and lower property tax collections. About 900 county employees face layoffs, Bean said.

"We were concerned when he came out with the number today it would be even worse," she said. "We're really thankful it held at the 13 percent because that's where we've been working."

Hillsborough County commissioners, who in past years have taken strong stands against tax hikes, are unlikely to raise the county millage rate to recover some of the lost valuation.

The Hillsborough County School District did raise tax rates last year when property valuations dropped 5 percent. It was the first time it had done so in years. The district collected $7.77 for every $1,000 of taxable property, up from $7.52 from the previous year. That translated to an increase of $44.45 for the owner of a $200,000 home who qualified for the $25,000 homestead exemption.

Since at least 2003, tax rates had been decreasing, said Gretchen Saunders, the school district's chief business officer. When told of the dip projected countywide, Saunders said, "I've never seen anything like that."

The school district already is facing a loss of about $9.5 million in the next year's state budget.