Stonehurst, made up mostly of aging rowhouses, and populated by working-class residents of many nationalities and cultures, did quite well after reassessment. Some tax bills there fell by a third.
The reason is simple, county officials say: Actual property values there have been falling for years, but that reality was not reflected in the tax assessments until now.
"We know about the 30 percent of the county that went up in assessments," said William S. Moon, manager of Delaware County's Board of Assessments. "But we're not hearing from the other 70 percent. I think the tax change will be a decent change for the people there in Stonehurst."
The shift of the tax burden from areas such as Stonehurst to areas such as Drexel Hill reflects a pattern of property values falling closer to Philadelphia and rising in roomier suburbs farther west, though exceptions to that rule pepper the county.
What causes a dramatic effect on tax bills is when one area within a single school district is rising in value while another is falling.
Thus, when the local share of the $92.5 million needed to fund Upper Darby's school budget is raised by taxing individual properties, lower tax bills at one end of town mean higher bills somewhere else.
Assessments in Upper Darby overall went down compared with the county average.
Thomas Micozzie, a member of Upper Darby Township Council representing the western edge of the town, said assessments in his neighborhood had risen significantly, and many residents had only a vague idea what that meant to their finances - until their school tax bills arrived this summer.
Cole Layer Trumble, the firm that reassessed all 198,000 properties in Delaware County last year for the first time in more than 50 years, had a goal of making everyone's property value reflect actual market value.