Most county jurisdictions raise revenue through Ad Valorem taxation. Ad Valorem literally means "According to value" and it is used to describe a tax system where the basis of the amount of taxes levied on something, such as real estate in the case of property taxes, depends on a valuation of that asset. Many counties also use an ad valorem basis to tax some personal property such as automobiles and boats as well as business assets.
"Tax Value" generally refers to the value of an asset that was determined by the taxing authority of a county or city. This is usually the job of the Tax Assessor's office.
By state law in North Carolina, all parcels in a county's jurisdiction must be revalued by the taxing authority minimally every 4 years but not more than every 8 years in order to update the values to a current "fair market value". Mecklenburg County is in the process of revaluation for the first time since 2003. In Mecklenburg County, the date of the revaluation was as of January 1st, 2011. The Tax Assessor's office has collected and measured available sale and income data from the market from the past few years to use in the revaluation of the county's 365,000 properties.