Over the last four decades, hundreds of thousands of suburbanites have fled Philadelphia, bidding an enthusiastic farewell to its wage tax.

But now wage taxes have caught up with them.

In 1960, no Philadelphia suburb had a wage tax. Today, 70 percent - 167 communities in the Philadelphia area - do, solidifying Pennsylvania's national ranking as the state with the highest percentage of communities with wage taxes.What's more, though wage taxes have been used to shift some of the tax burden from real estate, they have proved no guarantee against higher property taxes. State data show that, within the last four years, property taxes, even after adjusting for inflation and recent reassessments, have increased in 24 of 31 local school districts that have a wage tax.

The suburban wage tax - known more properly as the earned-income tax - is substantially smaller than Philadelphia's. Along with rising suburban real estate taxes and a menu of other levies, however, it has narrowed some of the tax gap between the city and the suburbs and between the Pennsylvania suburbs and those in New Jersey - with some of the highest property levies in the country but no municipal wage taxes.

"The focus is so much on the city wage tax that people forget that these taxes are in the suburbs, too," said Steven Wray, deputy director of the Pennsylvania Economy League.

The tax has become as much a part of the suburban landscape as cul-de-sacs, corporate campuses, and sport-utility vehicles, spreading so quietly and incrementally that, officials say, most people are unaware just how pervasively it is now levied.

Though it has set off rancorous debate in such communities as Hatfield Township, where it was about as welcome as a rush-hour road project when adopted two years ago, the wage tax has more commonly been a stealth tax, unnoticed by residents already paying it in a town where they work.

Typically, the wage-tax rate is 1 percent, with the town and school district splitting it. Those who live in the suburbs and work in Philadelphia pay the 4.01 percent commuter rate. (Philadelphia residents pay 4.61 percent.)

Under state law, the town of residence has first claims on the wage tax. Residents already paying 1 percent do not have to pay it in the town where they work.

But the law has one exception: Commuters who work in Philadelphia pay the wage tax there, not in the community where they live.

All the criticism of the Philadelphia tax hardly seems to be slowing the momentum in the suburbs. Many of the 30 percent of suburban communities that do not have a wage tax are likely to adopt one, local officials say, thanks to spiraling costs and simple demographics.

In fact, the holdouts in the Philadelphia region, clustered in Delaware and southern Chester Counties, are among the last in Pennsylvania - where 96 percent of the towns have a wage tax.

Wage taxes have spread "like a virus" across the state, says economist Koleman Strumpf, a local-government specialist who is an expert on municipal taxes. It was Strumpf, who works out of the University of North Carolina, who determined that Pennsylvania was the nation's wage-tax capital.

Many suburban residents are like Michael Malin, a lawyer who lives in Hatfield Township who figured that he had exorcised the wage tax when he left Philadelphia. He was not pleased when his township adopted the tax two years ago.

"I never thought that would happen," Malin said. "I really didn't. Neither did anybody else. A lot of them came here to get away from the wage tax."

Malin called his sympathy to the township's need for revenue limited.

"I consider myself a liberal Democrat, and I'm in favor of government doing what it can for people," he said, "but not at this level. I just don't like the idea of watching fiscal irresponsibility."

Malin fought the tax, unsuccessfully, but the dispute led to the ouster of one commissioner and the near-toppling of another via a write-in vote.

More recently, Hatfield Township doubled the rate - to 1 percent.

Political opposition has been more effective elsewhere. For example, in cash-strapped New Hope, which has some of the lowest property-tax rates in the region, an entire slate of council candidates recently won election on a promise to block any attempt to institute a wage tax.

The Bensalem School District has tried for a wage tax twice in the last two years, only to be voted down by the school board both times.

That vote ensured that David Fiedler, a holdout who lives in Bensalem Township and works in Lower Merion, would remain among the relatively few Pennsylvanians who pay no wage tax.

Fiedler, 53, works for HBO and pays about $3,200 in school taxes annually. He said he wouldn't mind a wage tax if it were to come with a guaranteed cut in property taxes.

"I don't have any problem with paying my fair share," Fiedler said, "but I feel I'm paying my fair share. [The wage tax] is a pretty unpopular idea here in Bensalem."

"No new tax is popular," said Edward Stack, school board president of the Neshaminy School District, which was looking at a $10 million shortfall last month.

What's more, the district stands to lose $660,000 if the legislature passes a bill cutting an amusement tax collected from the popular Sesame Place theme park.

Stack's solution: An earned-income tax of 0.5 percent that would raise about $6 million a year. The board, however, would have no part of it. Last month, Neshaminy approved a trimmed $113.8 million budget that called for a 9 percent increase in the real estate tax.

"We'll have a property-tax increase," Stack said, "and a significant one. I think that's regrettable."

In Delaware County, Thomas J. Bannar, Haverford Township's business manager, has been trying to sell the supervisors on adopting a wage tax for 15 years - to no avail.

"It just doesn't fly," Bannar said. "Politically, they're not going to vote for it, because they know it's the kiss of death."

Yet, he said, the town needs to find more money. Built-out Haverford is bleeding every last nickel from its real estate taxes, he said, and the overall property-tax base isn't going to increase, a common complaint, particularly in the older suburbs.

Experts cite several reasons for the proliferation of wage taxes in the Pennsylvania suburbs, including rapidly expanding school systems and the growing unpopularity of the state's property-tax system.

Though property taxes are hitting a ceiling, the cost of education and municipal services for growing populations - for police, trash collection, sewers, new school buildings - is steadily increasing.

"You get people moving out to new places where they didn't have big governments," said Wray of the Pennsylvania Economy League. "Now they do."

Perhaps the biggest boon to the wage-tax movement is Philadelphia's weakening gravitational pull on the regional workforce. Job growth has exploded in the suburbs and flattened in the city.

"The people went there, and the jobs followed them," said Thomas Walker, a transportation specialist with the Delaware Valley Regional Planning Commission.

Thanks to the Sterling Act, passed by the state legislature during the worst of the Great Depression, Philadelphia became the first city in the nation to enact a wage tax, in 1939. Even at a modest rate of 1.5 percent - a third of what it is today - it proved a gold mine for the job-rich city, according to David Thornburgh, executive director of the economy league.

Foreshadowing the tensions, however, neighboring communities fought to repeal the Sterling Act.

They failed.

In 1947, the legislature did pass a suburban version of the Sterling Act but with important differences. Unlike the city rate, which had no limit, the law capped the suburban rate at 1 percent. It also exempted all workers who were paying the Philadelphia tax, which ruled out half the workforce of some suburban towns.

Richlandtown in Bucks County enacted the first wage tax in the Philadelphia suburbs in 1962. It was quickly followed by nearby Quakertown, Riegelsville and Milford.

The law was written in such a way that it virtually guaranteed the spread of the wage tax, said Strumpf, the North Carolina economist.

It gave the towns of residence the first claim on wage taxes. Thus, someone who lived in Milford but worked in Quakertown would pay the tax to Milford.

"If your neighbor [town] has a tax, then your residents who work there will have to pay taxes there unless you have one," Strumpf said.

By 1970, more than 40 suburban municipalities had wage taxes, including such older towns as Phoenixville and Chester. The rate of spread slowed in the 1980s but picked up steam in the '90s with the additions of such towns as Warminster and Warrington in Bucks County, Kennett Township in Chester County, Darby in Delaware County, and Hatfield.

The wage tax has its administrative advantages over the property tax. Keeping up with property values requires expensive mass appraisals, and they quickly become obsolete as property values shift. Wage taxes are adjusted automatically. Plus, with a tax on wages, the elderly and others on fixed incomes get built-in tax breaks.

But the wage tax is flawed. By definition, "earned income" targets only wages, not investment income. A flat tax, it is not based on ability to pay but it is subject to economic conditions, thus volatile.

Finally, though widespread, it remains immensely unpopular in some areas.

"If I were to move now," said Marilyn Larson, who lives in Newtown Township and who is a former Council Rock board member, "I would not stay in this school district."