Why do I file my Pennsylvania assessment appeal the year before the tax year?

Unlike states where you appeal the bill you just received, Pennsylvania's annual appeal is forward-looking. The deadline set in 53 Pa.C.S. §8844(c) — on or before September 1, or a county-designated date no earlier than August 1 — governs the assessment used for the following tax year. An appeal filed in the late summer of 2025 sets your assessed value for the 2026 county, municipal, and school taxes.

Why it works this way. Counties certify assessment rolls before the tax year begins so that every taxing body — county, municipality, and school district — can set its millage rate against a final number. The statute requires appeals to be heard by October 31 and decisions mailed by November 15, leaving time for the certified roll to feed into the next year's bills.

What this means for you. Even if your current bill already looks too high, the relief from a successful annual appeal generally applies going forward, not retroactively to the bill in hand. To fix the current year you usually need a different path — an interim or special appeal tied to a specific notice (new construction, a catastrophic loss, or a correction), which carries its own short deadline.

County variations:

• Allegheny County sets a specific annual-appeal window each year (July 1 through early September for the 2026 tax year), administered by BPAAR. Confirm the current window at Allegheny County.
• Philadelphia requires a Board of Revision of Taxes market-value appeal by the first Monday in October of the year preceding the tax year.

Because the filing year and the tax year differ, mark next year's deadline as soon as you receive any change-of-value notice — waiting for the actual bill is usually too late.