The Philadelphia Board of Revision of Taxes voted unanimously yesterday to move forward with a plan that could lead to sweeping changes in the way property is taxed in the city.

The BRT will come up with new tax assessments for the city's 450,000 residential and 125,000 commercial properties based on 100 percent of their market values.

Property in Philadelphia is now assessed in a "fractional" system at 32 percent of its market value. The system is flawed, some of the seven BRT members said, because some property owners pay too much or too little compared with taxes on similar properties.

The BRT was eager to ease potential taxpayer fears about rising taxes, saying the new numbers - expected by the end of the year - will not be immediately implemented.

First, City Council and the Legislature must consider the impact of the new assessments and come up with programs and policies to protect some homeowners.

"We can't tell you how it will affect you now," BRT chairwoman Charlesretta Meade said at yesterday's hearing. "This is the first step in the process."

The initiative is not designed to bring in more taxes, although the assessed value of some properties could be increased to be more accurate. City Council is likely to vote to reduce the current property tax rate of 8.264 percent to even out the financial impact.

Mayor Nutter, who supported moving forward with the issue, this week said "simple math" suggests that the tax rate would be reduced. But he could not say by how much because the BRT is still coming up with the new assessment numbers.

The Legislature could also approve homestead exemptions in the city, rebates for senior citizens and rebates for property owners when their taxes exceed a percentage of their income.

The initiative, originally called the "Full Value Project," has been politically contentious since it emerged in 2003 from the city Tax Reform Commission.

City Controller Alan Butkovitz opposed the idea, telling the BRT the change should not become a "back-door" tax increase. "Frankly, I think you're biting off more than it's possible to chew," he warned.

Councilwoman Jannie Blackwell also has opposed the initiative. She warned that past efforts to reform tax collection have led to more problems.

"Every time we touch it, taxes go up," Blackwell told the BRT. "People just can't afford it."

Blackwell urged the BRT to not implement the initiative until the city and state comes up with protections for property owners.

Although the board voted unanimously to move forward, its members didn't always appear on the same page on the issue.

Board member Joe Russo, just before the vote, said he wanted to avoid setting a deadline to implement it. Board member James Dintino agreed with that notion after the vote. Board member Russell Nigro said the BRT has an obligation to treat taxpayers fairly, even if Council and the Legislature don't take action.

"So we would like to have a partnership and work this out and have it come out to be exactly the way everyone would like it to be," he said.

"But we can't drop the ball on our end and do nothing at all." *