First, contact your local township assessor. He/She is most familiar with your property and the person directly responsible for the assessment of your property. Perhaps you can provide additional information regarding your property that would affect the assessment.
If no adjustment is made here, you will need to file an assessment appeal with the Board of Review. The Board of Review is a three-member panel appointed by the Rock Island County Board to review assessment appeals. The Board of Review examines evidence you have submitted and determines if an accurate and fair value has been placed on the property by the assessor or CCAO. Evidence can be a number of things: a recent appraisal, sales in your area, photographs of the physical conditions, (if your issue is market value) or a chart of comparable property assessments (if your issue is equity).
The next step in the appeal process is the State Property Tax Appeal Board. This is a five-member panel that reviews the local Board of Reviews assessments.
Note: You will not win an appeal because you think your taxes are too high. Assessment officials can only determine assessments, not taxes.