What is the Common Level Ratio (CLR) in Pennsylvania and how do I use it to appeal?

Pennsylvania does not require counties to reassess on a schedule, so most counties tax off an old "base year." The Common Level Ratio (CLR) is the bridge between that stale base-year number and today's market. It is the ratio of assessed value to current market value, calculated each year by the State Tax Equalization Board (STEB) from county sales-ratio studies and certified to county assessors before July 1.

How the CLR controls an appeal. Under 53 Pa.C.S. §8842(b), the board first finds your property's current market value as of the date the appeal was filed, then applies the county's established predetermined ratio to that value — unless the CLR last published by STEB varies by more than 15% from the predetermined ratio, in which case the board must apply the CLR instead. In counties with old base years, the CLR is usually far below the predetermined ratio, so the CLR controls.

Why it wins appeals. If your home would sell for $300,000 and the county CLR is 50%, your assessment should be about $150,000. If the county currently assesses you at $200,000, that implies a market value of $400,000 at the same ratio — clear grounds for a reduction. The CLR converts your evidence of market value into the correct assessed value automatically.

Key 2026 fact: Allegheny County's CLR dropped to 50.14% for 2026 (from 54.5%), per STEB — meaning a homeowner now needs less of a market-value gap to win. Each county has its own CLR; check STEB's annual certification for yours. Bring recent comparable sales or a current appraisal as your market-value evidence, and let the CLR do the rest of the math.