Pennsylvania has no statewide reassessment mandate, so counties value property as of a 'base year' that can be decades old. That sounds like a mess — and it is — but it also creates a clear, formula-based path to a reduction through the Common Level Ratio.
Deadlines vary by county
There is no single statewide appeal deadline. Many counties use an August 1 deadline for annual appeals, others use September 1 or the first Monday in October, and Philadelphia runs its own system through the Board of Revision of Taxes with its own date. The one universal rule is to confirm your specific county's deadline early.
Do not assume a neighbor's or another county's deadline applies to you. Pennsylvania appeal deadlines genuinely differ from county to county, and missing yours ends the appeal for the year.
The Common Level Ratio — Pennsylvania's key tool
Because base-year assessments drift away from current values, the State Tax Equalization Board publishes a Common Level Ratio (CLR) for each county every year — the ratio of assessed values to current market values. To test your assessment, multiply your property's current market value by the county's CLR: that product is roughly what your assessment should be. If your actual assessment is meaningfully higher, you have a CLR-based case for a reduction.
How to appeal
- Confirm your county's deadline and get the appeal form from the county Board of Assessment Appeals.
- Establish your property's current market value with comparable sales or an appraisal.
- Apply the current county CLR to that market value to show your implied fair assessment.
- Present both at your hearing; if unsatisfied, you can appeal to the county Court of Common Pleas.
Evidence that wins
- Recent comparable sales establishing current market value.
- The current-year Common Level Ratio for your county.
- An appraisal for higher-value properties or Common Pleas appeals.
Look up your county's current Common Level Ratio before filing — it converts today's market value into the base-year terms the board uses, and it is often the single most persuasive number in a Pennsylvania appeal.
Sources & currency: Pennsylvania's county-by-county deadlines, the role of the State Tax Equalization Board's Common Level Ratio, and Philadelphia's separate process were reviewed as of July 2026. CLRs are published annually and deadlines vary by county — confirm both with your county before filing.