Allegheny County Chief Executive Dan Onorato yesterday rolled out his latest 2006 assessment plan, calling for increases of nearly 6 percent in residential property values.

In a top-to-bottom rewrite of the first countywide reassessment in more than three years, the values assigned to 500,000 residential properties would go up an average of 5.8 percent, a sharp drop from the 19 percent average increase that the county posted online eight months ago.

By Friday, property owners will be able to see the new values on the county's real estate Web site: www2.county.allegheny.pa.us/realestate/search.asp.

About 407,000 residential properties would see at least some increases; and 25,000 would see decreases. About 69,000 would see no change.

But the new values already face at least one hurdle. James C. Clifton, a Franklin Park homeowner, has threatened to sue if County Council approves the chief executive's plan, arguing that the first batch of 2006 numbers met the standards of the International Association of Assessing Officers. He and the Sto-Rox School District successfully blocked Onorato's plan to put a 4 percent cap on those numbers.

Onorato told council last night he is confident that the new values would address the concerns of Common Pleas Judge R. Stanton Wettick Jr., who threw out the 4 percent cap in May and ordered the county to correct problems with its assessment system.

In his decision, Wettick said "an assessment system that is not based on the actual fair market values of all properties within the taxing body is not an accepted assessment standard."

In sending his proposal to council, Onorato said Wettick had made it clear that "doing nothing is not an option."

Onorato also defended his decision to drop the association standards from the county administrative code, saying that state law, the county home rule charter, and Wettick's May decision don't require them.

"Allegheny County is being held to a much higher standard than the counties around us," he said.

Onorato said the reassessment took into account a range of factors, including appeal results from January 2002 to July 2005. Normally, a reassessment discards appeal results.

Under the new figures, the county's 50,000 commercial properties would see a 12 percent increase, and the county as a whole would see an average increase of 7.6 percent.

Council must approve Onorato's plan before the new numbers can be certified and mailed to property owners. The county, school districts and municipalities will use the numbers to set their tax rates for next year.

Two council Republicans who voted against Onorato's cap plan expressed strong doubts about his latest proposal during last night's meeting.

"Your bill lacks any hard standards," Councilman Doug Price, R-Carnegie, told Onorato. "That concerns me."

Councilman Ron Francis, R-Ben Avon, said he didn't think the new assessed values would fare well when compared to actual sales of properties in the county.

"Even though the numbers may be lower, they're less uniform," he said. "That's going to be one of the roadblocks you're going to run into if this goes before Judge Wettick."

Onorato said the number of actual sales was not always large enough to reflect accurately values in the county as a whole. And he argued that his new numbers would still be more accurate than figures generated by other southwestern Pennsylvania counties.

"We're just too heavily taxed right now," Onorato said.

Councilman John DeFazio, D-Shaler, agreed.

"Poor people are saying, 'I want to move to other counties,' " he said. "I don't care what system you eventually use. If, at the end of the day, it's lower and better for the majority of the people, I don't see how we can vote against it."

Council's Special Committee on Property Assessments will consider the chief executive's bill at its meeting Tuesday, said council President Rich Fitzgerald, D-Squirrel Hill.

If council approves the bill at its Oct. 4 meeting, the county's chief assessment officer, Deborah Bunn, would certify the new numbers. Property owners and taxing districts would have until Nov. 18 to appeal.

Robert Strauss, a professor of economics and public policy at Carnegie Mellon University, said commercial property owners may complain that homeowners would receive a bigger break under the new numbers.

"That seems to be saying that the commercial market is stronger than the residential market," he said. "But vacancy rates Downtown don't support that."

Next month, Onorato will present a preliminary 2006 budget to council, and he said yesterday that he plans to reduce the county millage rate to prevent the rising assessment values from leading to tax increases.

"We will call on the municipalities and school districts to do the same thing," he said.