You probably linked here from The Great Pennsylvania Property Tax Calamity Page. If you didn't, and if you're wondering about assessments in Columbia County, or any county in Pennsylvania for that matter, please read what's on that page. On the other hand...

If you already know more than you want to about property assessments, consider what is written on this Columbia County Assessment Office web page.

Columbia County tax assessors give you the impression they are trying to be helpful by asking your question for you: What is "Market Value?" They answer with this: Market Value has been defined by the State Supreme Court as "the price in a competitive market a purchaser, willing but not obligated to buy, would pay an owner, willing but not obligated to sell, taking into consideration all legal uses to which the property can be adapted and might reasonably be applied."

Then, because their idea of fair market value almost certainly isn't what you thought it was, they also ask your obvious next question for you: Isn't "Market Value" what I paid for my property? Their answer is wherein lies a big problem: Not always. Depending on the circumstances involved in a sale, some people may have overpaid for a property. On the other hand, others may have purchased their property at a bargain price. Properties purchased years ago are not reflective of what properties are worth today. The true test is what is your property worth TODAY.

Ignoring the passage of time, assuming you have recently purchased a property in Columbia County, we need not deal with the next to the last sentence of their answer. The Columbia County tax assessors cover themselves with the Depending on the circumstances phrase, but if you're a recent buyer in an above board sale of a property that was on the market a reasonable amount of time, and if you did any negotiating whatsoever with the seller, and you plan to use the property for a legal purpose for which it's generally suited, especially the same purpose the seller was using it for, what you paid is exactly what the Supreme Court of Pennsylvania says "fair market value" is. No more, no less. Is that not precisely what "your property is worth TODAY" to use their words? Any county that tells you otherwise is engaging in classic Big Brother behavior which is integral to the Pennsylvania Property Assessment We-Say-So Merry-Go-Round. In this case, the Columbia County tax assessors are telling you right up front that they don't care what the Supreme Court of Pennsylvania has ruled, they're going to do what they want.