TAMPA - For the first time since 1992 the value of taxable property in the city and county has declined.

The city's 3 percent drop and the county's 6 percent drop are largely because of the passage of Amendment 1 in January and are more severe than previously projected declines. The drops are in sharp contrast to the double-digit increases enjoyed by both governments for the past several years.

The property appraiser's office was able on Wednesday to track tax value records to 1974. The 1992 decline was the only other drop during the 34-year time period.

The portability provision of Amendment 1 alone had a $50 million impact on the taxable value of property in the city and a $160 million impact in the county.

Property values have a direct effect on local governments' budgets and residents' pocketbooks because property taxes are the largest funding source for city and county budgets.

The numbers are still estimates, but give governments a sense of how the referendum affects their budgets, said Tim Wilmath, director of valuation for the county property appraiser's office. Firmer estimates should be available in June.

The decline means the city will bring in about $5.8 million less in property taxes next year compared with this year, forcing government officials to continue looking for budget cuts. Layoffs are expected.

"We have spent the past year spending less," Mayor Pam Iorio said. "We just have to be realistic about what's happened to our property tax base."

The value of taxable property in the city was $29.5 billion on Jan. 1, 2007, but declined by $900 million a year later, to $28.6 billion, according to the estimates.

If Amendment 1 had failed, the city tax base would have been $30.2 billion, a $700 million increase.

At the county, the value of taxable property for 2007 was $87.7 billion but dropped to $82.2 billion by Jan. 1, 2008.

The $5.5 billion drop was largely because of property value shielded by Amendment 1; without that tax-cutting measure, the 2008 value would have been about $88.5 billion.

In January, voters overwhelmingly sent a message to government officials: spend less and tax us less. The referendum doubled the homestead exemption from $25,000 to $50,000, though school taxes are exempt, and allowed homeowners to transfer Save Our Homes tax benefits to a new homestead. Businesses can exempt up to $25,000 of tangible property.

Each element has an effect on the city and county's taxable property values.

Increasing the homestead exemption took about $1.3 billion from the city's taxable property base, and about $5.6 billion from the county's.

"That really puts a big hit on the city," Wilmath said.

The tangible property exemption hit the city's tax base to the tune of $198 million and the county saw a $511 million decline.

And the portability component has a $50 million impact on the city and a $160 million impact on the county. The county received about 5,000 applications to transfer a homestead exemption from one property to another.

Eric Johnson, the county's budget director, said he considers the numbers preliminary at best, but if they hold up, "We're in worse shape than we had planned, and we would have to cut further to bring the budget into balance."

The updated numbers mean the city expects to receive about $155.8 million from property taxes in 2009, down from $161.6 million in 2008, said Bonnie Wise, the city's director of revenue and finance.

Meanwhile, other revenue sources are declining as well, Wise said, particularly sales taxes.

The state in June estimated Tampa would get $30.5 million in sales taxes this year, then in December revised its estimate to $29.5 million.

The city later dropped its projections even more, to about $27.9 million. This week, Wise said that number could easily fall another couple hundred thousand dollars.

"It's even worse," Wise said. "The market is deteriorating further."

Reporter Ellen Gedalius can be reached at egedalius@tampatrib.com or (813) 259-7679.