Real Estate Law · Allegheny County
Allegheny County Property Assessments: The 2012 Base Year, the CLR, and What Triggers a Reassessment
Pennsylvania law permits counties to maintain a base-year assessment system under 53 Pa.C.S. § 8842, which allows property values to remain fixed to a historical baseline until a countywide reassessment occurs. Allegheny County has operated under a 2012 base year since its last countywide reassessment. The Pennsylvania State Tax Equalization Board annually calculates a Common Level Ratio (CLR) to measure the gap between assessed values and current market prices. For 2026, the CLR stands at approximately 50.14 percent, meaning assessed values represent roughly half of current market value countywide.
Related practice areas and resources: For guidance on filing an assessment appeal once reassessment occurs, see our page on Allegheny County Property Assessment Appeals. For questions about real estate transfers and deed recording, see our Real Estate Transactions page.
What Is the Common Level Ratio in Pennsylvania?
The Common Level Ratio is a statistical measure calculated annually by the Pennsylvania State Tax Equalization Board to determine the relationship between assessed property values and actual market prices within a county. In counties using a base-year assessment system, the CLR quantifies how far assessed values have diverged from current market conditions. The calculation reviews recent arm’s-length property sales and compares the sale prices to the assessed values on record. When the CLR is 50 percent, assessed values represent approximately half of what properties would sell for on the open market. Property owners may use the CLR during an assessment appeal to argue that their assessed value should align with the countywide standard. The CLR does not automatically change a property’s assessed value, but it provides the legal benchmark for challenging an assessment that appears disproportionate to market conditions. Pennsylvania law requires the State Tax Equalization Board to publish the CLR annually for each county, making it a publicly available reference point for assessment disputes.
The 2012 Base Year
Pennsylvania law allows counties to use a base year system for property assessments. Under this system, the county establishes a baseline year for valuation and maintains those values until a countywide reassessment occurs. Allegheny County’s base year is 2012.
As a result, many long-term property owners pay taxes based on values that reflect market conditions from more than a decade ago. A home that might sell today for $400,000 may still carry an assessed value closer to its 2012 price. This disparity between assessed value and current market value is the natural outcome of a base-year system operating in a rising real estate market.
How the CLR Affects Property Taxation
Allegheny County’s 2026 CLR is approximately 50.14 percent. In practical terms, this means the county’s assessments represent about half of current market value on average. The CLR operates as a legal mechanism to maintain uniform taxation across properties that were last valued at different points in time.
In an assessment appeal, property owners may use the CLR to argue that the assessed value should reflect the countywide relationship between assessments and market prices. The CLR becomes particularly relevant when a property has been reassessed following a sale or transfer, and the new assessed value appears disproportionately high compared to the countywide standard. A property reassessed at 80 percent of its sale price would be taxed at a higher effective rate than properties still valued under the 2012 base year at 50 percent of current market value.
What Can Trigger Reassessment
While the 2012 base year remains in place for many properties, certain events can bring a property back in front of the assessor. A sale of the property is the most common trigger. When a property sells, the county may reassess it based on the sale price rather than the historic base-year value. This creates a two-tier system where recently sold properties may carry assessed values closer to current market rates while long-held properties remain anchored to 2012 values.
Other recorded transfers can also attract attention. Deeds transferring property between family members, transfers into an LLC, or distributions of real estate through an estate administration may result in the county reviewing the property’s assessed value. Whether a reassessment occurs depends on how the county processes the transaction, but the possibility should always be considered before a deed is recorded. Call 412-351-4422 or schedule a consultation before recording a deed or completing a property transfer.
Two Different CLR Calculations
Allegheny County property owners sometimes encounter two different CLR-related numbers that operate in opposite directions. The appeal CLR, currently about 50.14 percent, is used when challenging an assessment. It reflects the relationship between assessed values and market prices across the county.
A separate factor is used when converting assessed values to estimated market values for certain legal purposes, including realty transfer tax calculations and inheritance tax reporting. That factor may produce a number much closer to current market value. The distinction is important for property transfers and estate administration because the value used for tax reporting may differ significantly from the value shown on a property tax bill.
Potential Changes to the System
State lawmakers have periodically proposed legislation requiring counties to conduct reassessments at regular intervals. If such legislation passes, Allegheny County would eventually move away from the 2012 base year and reassess all properties based on current market conditions. Until that occurs, the base-year system will continue to produce disparities between long-time property owners and more recent buyers.
Pennsylvania property assessment law is governed by Pennsylvania statutes including the General County Assessment Law and supplemental provisions for second-class counties. Procedures for filing appeals and conducting hearings are administered through the Pennsylvania Unified Judicial System.
Questions About Property Assessment or Reassessment
The law sets deadlines. Missing them closes options permanently.
This article provides general information about Pennsylvania property assessment law. It does not constitute legal advice. Assessment appeals and property transfers involve specific deadlines and procedural requirements that vary by jurisdiction and circumstance.
Related Practice Areas: Real Estate Issues · Allegheny County Property Assessment Appeals · Pennsylvania Inheritance Tax · Real Estate Transactions
Stephen H. Lebovitz, Esq. is a third-generation Pittsburgh attorney and the principal of Lebovitz & Lebovitz, P.A., a firm serving Pittsburgh and Western Pennsylvania since 1933. His practice focuses on estate planning and probate, real estate, family law, business law, and personal injury. He handles each matter personally, from initial consultation through resolution. The firm is based in Swissvale, near the Parkway East (Swissvale–Edgewood exit), serving clients throughout Allegheny County and southwestern Pennsylvania.