Each county in the state of Pennsylvania will determine its own appeal deadline.  

The Allegheny County 2026 property tax assessment appeal deadline is September 2, 2025.

For a list of deadlines in other counties, click here.

Every county has a “base year” for tax assessment purposes. Property assessments are supposed to reflect a base year valuation.

The base year for Allegheny County is 2012. The CLR is a ratio which is intended to convert present day market values into base year assessed values.

The CLR in each county is adjusted annually based on sales data selected in their county.

For example, in 2026, Allegheny County’s CLR will drop to 50.1%.  Five years ago, Allegheny County properties were assessed at 86.2% of market value.  At that time, a property worth $1,000,000 was assessed at $862,000.  Today a $1,000,000 property should be assessed at $501,000.

Yes, CLR applies to commercial, industrial, and income producing properties.

When it works to their benefit, taxing authorities chase new sales and seek an increase in assessed value. In doing so, the taxing authorities are essentially asking that a new “snapshot” of market value be taken and the current CLR applied to the purchase price of the property. 

No, you must file a tax assessment appeal to get the benefit of the reduced CLR ratio. If you do not file an appeal, no one will file an appeal for you and you will not benefit from the reduced CLR. Taxing authorities only file tax appeals on properties where they believe they can increase the property’s assessed value, resulting in higher property taxes.

Property taxes are based on assessed value. Assessed values are taxed at the millage rates set by your County, school district, and local municipality. Assuming no change in millage rates, a lower assessed value means lower property taxes. Taxing authorities may increase their millage rates to avoid a large drop in tax revenue resulting from fewer assessed dollars. If millage rates increase, each assessed dollar will be taxed more. In a rising millage rate environment, property owners will see tax increases unless they can reduce their assessed value via a tax assessment appeal.

The answer to this question will vary based on each property’s use, market value, current assessed value, improvements made to the property, and the strategies available to obtain a reduction for that property. The attorneys in Meyer, Unkovic & Scott’s Real Estate Group have substantial experience representing property owners with property tax assessment appeals throughout Pennsylvania.