What is a base year in Pennsylvania property assessment?
What is a base year in Pennsylvania property assessment?
A Pennsylvania base year is the year of a county's last countywide reassessment, whose values the county keeps using indefinitely; the Common Level Ratio adjusts those frozen base-year numbers toward current market value for appeals.
Pennsylvania is the only state that does not require periodic countywide reassessments. Instead, 53 Pa.C.S. §8842(a) lets a county adopt a base-year market value — the values established in its most recent countywide reassessment — and continue using them year after year without updating to current market value.
Why base years drift so far from reality. Because there is no reassessment mandate, many counties have base years that are decades old. Reported examples range from counties last reassessed in the 1960s to others reassessed only recently. The longer the gap, the more individual assessments diverge from what homes actually sell for today — which is exactly why appeals work.
How the base year and the CLR interact. Your assessment is stated in base-year dollars, not today's dollars. To make a base-year assessment comparable to a current sale price, the State Tax Equalization Board publishes a Common Level Ratio (CLR) each year. On appeal, the board determines your property's current market value and applies the CLR (when it varies from the predetermined ratio by more than 15%, per §8842(b)) to translate that into the correct base-year assessment.
What this means for your appeal. Don't compare your assessment directly to recent sale prices — they're in different units. Instead, take your current market value, multiply by the county CLR, and compare the result to your assessed value. If your assessment is higher than market value × CLR, you are over-assessed.
Note on spot reassessment. A county may not single out your property for a fresh reassessment outside a countywide program; 53 Pa.C.S. §8843 prohibits "spot reassessment." Routine changes for new construction or improvements are handled separately as interim assessments.