If you or anyone else is interested, i can explain it. I once was a realestate appraiser.
The tax assessor determines the value of your property, but they are only accurate when it comes to the "land value" portion. When it comes to the "improvement value" (the value of the house or building on the property), they are ALWAYS way below the actual value. The reason for this is because you have to spend at least one day to find "comparison appraisals" (usually 3-4 comparible homes recently sold). Tax assessors dont have the time to do that to every home in the nation, so they make a guess and intentionally make dure that its low, otherwise they would be getting sued by everyone for making them overpay their taxes.