The property tax value for a registration renewal is based on the January 1 value and your assigned renewal month. January through August renewal months use January 1 value from that period. September through December renewal months use the January 1 value immediately after that period. The owner may file a written appeal of the appraised value with the County Tax Office within 30 days of the due date shown on the front of your vehicle renewal registration. Taxes are to be paid on the motor vehicle when they are due and are subject to a full or partial refund if the appeal is decided in the owner's favor.