1. Your appraised value is NOT based on an individual property assessment.
Instead, the proposed value of your home was probably determined by mass appraisal. Appraisal districts usually don’t have adequate staffing or time to check every home individually. This means that even though your home was built and has depreciated uniquely, it is valued based on other properties.
2. The current economic value of properties has either grown or declined.
When the larger economy grows, appraisal districts increase values, however when the economy is in decline it is incredibly unlikely that these values will be reduced. More importantly, your property taxes remain high.
3. Your property value has decreased, but your tax (millage) rate was increased.
Local governments rely on taxation to meet their annual budget. However, government budgets will rarely, if ever, be reduced. This means that when your property value has decreased, such as when materials have depreciated, you could be paying more in taxes if the millage rate increased by a small fraction.
4. Foreclosure homes can be used as comparrisons to reduce your property value.
As of January 1st, 2010, the appraisal district may not exclude a residence homestead when used as a comparable property for helping to determine the market value, if the property was sold in foreclosure in any of the three years preceding the tax year your home is being valued.