The 2026 19% Delaware County property tax increase has now been in effect for six months. For homeowners who believe the assessed value driving their bill is too high, the annual window to do something about it closes at the end of the month.
The Delaware County Board of Assessment posted 2027 residential, commercial, and exemption appeal application forms on its Board of Assessment page in March. Under Pennsylvania county assessment law, the annual appeal deadline for Delco is Friday, August 1. Appeals must be either hand-delivered or postmarked by that date, and the Board's official notice reminds filers that "facsimiles and electronic filings are not acceptable" and that a hand-cancellation at a Post Office counter is the safest way to guarantee timely mailing.
The math is unforgiving. Because the county assessed all properties in 2021 based on 2019 market values, the Common Level Ratio Delco applies to convert current market value into assessed value has drifted; a home that has appreciated more slowly than the ratio assumes is now over-assessed and over-taxed. Radnor Township is one of the higher-median-value municipalities in the county, which means the arithmetic gap between fair market value and assessed value tends to run in the taxpayer's favor and is worth checking.
Appeals filed by August 1 apply to the 2027 tax year, which spans the January 2027 county bill, the July 2027 township bill, and the summer 2027 school district bill. A modest assessed-value reduction compounds across all three.
How to file
Forms and instructions are at the Board of Assessment page. Mailing address: Board of Assessment and Appeals, Government Center Building, 201 West Front Street, Media, PA 19063. Board staff Jess Wu (610-891-4879) handles appeal information questions.