A higher bill or a new assessment notice is unsettling, and the first useful thing to know is that a Philadelphia property tax increase almost always traces back to one of a small number of causes. Your bill is essentially your assessed value times a fixed rate, minus any exemptions — so if the number went up, either the value rose, an exemption or abatement fell away, or the way the bill is computed changed. Here's how to tell which one hit you, and what each one means for whether you should act.
This is the most common reason a bill jumps. The Office of Property Assessment (OPA) periodically re-values properties across the city using mass appraisal, and when your assessed (market) value rises, that increase flows straight into your bill at roughly 1.4% of the new value. Nothing about your home has to have changed — the model simply re-read the market and landed on a higher number. If your notice shows a new, larger market value, a reassessment is almost certainly what you're looking at. Our reassessment guide walks through what a citywide re-valuation is and how to respond to one.
Here's the part worth sitting with: a reassessment done by mass appraisal can overshoot. The model values hundreds of thousands of parcels at once by leaning on groups of similar, recently sold homes, and where your home is unusual, or the comparable data is thin, it has to reach — and reaching is how it lands above what the market would actually pay. A reassessment increase is not automatically correct just because the City issued it. That's exactly what an appeal corrects.
The test is simple in principle: does your new assessed value line up with what genuinely comparable homes near you have actually sold for? If it sits meaningfully above those real sales, you have grounds. Start with our self-check on whether your home is over-assessed, and if the gap looks real, our guide to how the appeal works lays out the steps.
A reassessment increase is a claim about your home's value — not a verdict. If the claim overshoots, an appeal is how you correct it.
The Homestead Exemption reduces the taxable value of a primary residence, so if it drops off your account, the rate is suddenly applied to a larger number and the bill rises — even with no change in your assessed value at all. This happens more often than people expect. The exemption can lapse if it was never reapplied after a change to the property, or if the home changed hands and the new owner hasn't filed for it. Pull up your bill or your OPA record and check whether the exemption is still listed. If it's your primary residence and the exemption is missing, you can apply to restore it — our Homestead Exemption guide explains how, and who qualifies.
If your property carried a tax abatement, that's another common trigger. An abatement exempts the value of improvements — new construction or major renovation — from taxation for up to ten years. While it runs, you're taxed on much less than the full value of the property. When it expires, that previously-exempt improvement value becomes taxable, and the bill steps up to reflect what was always going to come due. A large increase timed to the end of an abatement period is usually this, not an error. Our new-construction abatement guide explains the ten-year arc and what happens when it ends. Even so, it's worth confirming the underlying assessed value is fair — because from here you pay the full rate on it every year.
Finally, the mechanics themselves. Philadelphia's property tax is calculated by taking your assessed (market) value, subtracting any exemptions such as Homestead, and applying an effective rate of about 1.4% — 1.3998%, split between the City and the School District. Because that rate is a straight percentage of value, even a modest rise in your assessment produces a proportional rise in the bill, and the loss of an exemption shows up the same way. Understanding the arithmetic is what lets you attribute an increase to the right cause rather than guessing. Our walkthrough of how Philadelphia property taxes are calculated shows the full computation step by step.
Work down the list. If your notice shows a higher market value, it's a reassessment — and the real question becomes whether that new value is fair or whether the model overshot. If your value didn't change but the bill still rose, check your Homestead Exemption and whether an abatement just ended; those explain increases without a value change. If none of that fits, re-check the record itself for a plain error — an overstated square footage, a wrong room count, a feature that isn't there — because a factual error in the OPA record is one of the cleanest grounds for a reduction.
The one cause you can actually push back on with an appeal is an assessment that came in too high. If your increase is a reassessment that overshot, an appeal is the remedy — and a free check tells you in minutes whether yours is worth filing.
Yes. A reassessment is not final, and disagreeing with the new market value is exactly what the appeal process exists for. You can request a First Level Review using the form and deadline on your notice, or file a formal appeal to the Board of Revision of Taxes, whose deadline is generally the first Monday in October of the year before the tax year — confirm the current-year date on your notice or at phila.gov. If the new value overshoots what comparable homes actually sold for, that gap is your case.
Several things can split two neighboring bills. A reassessment can move one home's value more than another if the model read them differently. One of you may still hold the Homestead Exemption while the other lost it. One property's abatement may have expired while the other's is still running, or never had one. And record differences — square footage, condition, an added feature — feed different values into the same rate. The bill is value times rate, so any of those inputs changing yours and not theirs produces exactly this.
It's worth checking, because losing it raises the taxable value the rate is applied to. The exemption is for a primary residence and can drop off if it was never reapplied after a change, or if the property changed hands and the new owner hasn't filed. Look at your bill or your OPA record to see whether the exemption is still listed. If it's a primary residence and the exemption is missing, you can apply to have it restored.
Very possibly. A tax abatement exempts the value of improvements for up to ten years, so while it runs you're taxed on far less. When it expires, that previously-exempt improvement value becomes taxable, and the bill steps up to reflect it. A jump timed to the end of an abatement period is usually this and not an error — but it's still worth confirming the underlying assessed value is fair, since you'll now pay the full rate on it every year.
Compare your new assessed (market) value against what genuinely comparable homes near you have actually sold for. If your value sits meaningfully above those real sales, a mass-appraisal model likely overshot, and that gap is the basis for an appeal. A free check against the City's own recorded sales tells you in minutes whether the increase reflects a fair value or an over-assessment worth filing on.
TaxAssessmentIQ gives you a free, honest verdict from the City's own recorded sales — just enter your address, no sign-up and no account. If your home looks over-assessed, you can get a ready-to-file appeal packet for a flat, one-time price, backed by a money-back guarantee. If it isn't worth filing, we tell you that too — for free, before you pay anything.