Every 6 months, the county sends mails property owners a change of value appraisal of their property. Whatever value that card says the tax value of the property is worth, is what the tax value of their property is. Whatever improvements owners have made is not factored in and thus the Real Estate companies make their value decision based upon their independent review of the property on inspection. There can be various conditions that would lower the value of a property that adjacent properties may not have.