Your evidence packet is the set of documents you gather to show why the assessed value (the dollar figure the county places on your property for tax purposes), the recorded property characteristics, or the classification may be wrong. A short, organized packet can work better than a large pile of unrelated documents, so it helps to start with the notice and then build the packet around the reason for your appeal.
Start with the assessment notice
The assessment (the county's official valuation of your property) is announced to you on an assessment notice, and that notice is where you begin. It gives the value being appealed, the parcel number, the property address, the notice date, and the filing deadline or appeal period. Save the full notice rather than a screenshot of one section, because you will need every one of those details later.
Cook County explains that an appeal is intended to correct the accuracy of the property assessment, and that the assessor (the official who sets your property's assessed value) does not set tax levies, rates, or bills. That distinction matters, because your appeal argument works best when it focuses on value, uniformity, exemption status, or property data.
Add the property record card
The property record card is the county's file on your property, and it shows the data the assessor used. That data may include the land size, building size, property class, age, exterior, improvements, and other characteristics. Use the record card to show the appeal office exactly what information was reviewed and which details may be wrong.
The Illinois Department of Revenue lists a copy of the property record card and a photo of the property under appeal as evidence, and it also lists property record cards and photographs of similar properties in the neighborhood.
Add photos that prove the condition
Photos can support a claim about condition, damage, unfinished space, missing improvements, construction issues, vacancy, water damage, or repairs. Use dated photos when you can, and take both a wide photo that shows the area and a detail photo that shows the specific issue. Label each photo with the property address, the date, and a short description so the reader knows what they are looking at.
Miami-Dade lists date-stamped damage photos, repair estimates, invoices, receipts, and insurance documentation as examples of supporting documents for assessment review.
Add comparable sales or comparable assessments
Comparable sales are recent sale prices of other properties much like yours, and if your appeal is based on market value they can support the value you are requesting. Choose properties that are close in location, similar in size, similar in age, similar in condition, and sold near the valuation date the assessor used. California's State Board of Equalization says comparable sales closest in time are the best indicators of value, and that an appeals board may not consider comparable sales that occurred more than 90 days after the value date set by the county assessor.
If your appeal is based on uniformity, meaning whether your property is assessed evenly with similar ones, comparable assessed values may matter instead. Cook County explains that comparable properties are reviewed to determine whether the assessed value is in line with other similar properties.
Add purchase documents, appraisals, or repair records when relevant
A recent closing statement, purchase contract, appraisal (a professional estimate of your property's value), contractor estimate, insurance record, repair invoice, or inspection report may help when it is directly tied to the value issue. Avoid attaching documents that do not support your appeal reason, because a large packet with unrelated material can make the issue harder to follow. Keep the packet tied to one or two clear points.
Use a clear packet order
A consistent order helps the reader follow your case from the top. Arrange the packet like this:
Packet order:
- Cover page with property address, parcel number, and requested value.
- Assessment notice.
- Property record card.
- Short explanation of the appeal reason.
- Evidence for property data errors.
- Evidence for condition issues.
- Comparable sales or comparable assessments.
- Appraisal, purchase documents, or repair records if relevant.
- Proof of filing or delivery.
Common mistake
The most common mistake is filing your appeal first and collecting proof later. Some appeal offices require evidence by a specific date, and some boards only consider evidence presented at the hearing, so confirm your local evidence rule before you file.
Build your appeal. Check your assessment.
Owedify's Property Tax Appeal Kit turns your answers into an appeal letter and evidence packet, tracks your filing and hearing deadlines, and helps you line up comparable sales in one place. You review, sign, and send everything yourself.
Get the KitDisclaimer: This article is educational self-help information, not legal, financial, or tax advice. Property tax rules and appeal deadlines vary by county and state. Confirm dates from your own assessment notice.