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Blog · Evidence · 2026-08-03 · 2 min read

Documenting a factual error in your property record

The easiest win available, and it needs evidence rather than argument.

If the county's record says something untrue about your house, correcting it is simpler than any valuation argument — you are not disagreeing, you are pointing at a mistake.

Get the record card

Ask the assessor for the property record card. It lists square footage, room counts, basement finish, garage, porches, year built, sometimes a sketch. Read every line against reality.

Common errors worth checking

What proves it

Photographs, dated and captioned. A survey or plat for lot size. Architectural plans. A contractor's letter. A demolition permit. For square footage, a measured sketch with dimensions — measure the exterior footprint per floor and show your working.

Where to take it

The township assessor first. This is precisely the kind of thing they can fix without a hearing.

This is general information about how Illinois assessments and appeals work. It is not legal advice, not an appraisal, and not a prediction about your case. Deadlines and rules differ by county — check yours with your Board of Review.

Check your own assessment free →

More on Evidence

How to find comparable properties for a tax appeal Start from the county's own records, not from what you know about the neighbourhood.What makes a comparable good enough to use Similarity on recorded attributes, proximity, and nothing clever. Four tight ones beat twenty loose.Using your county's parcel search like an assessor would Every Illinois county publishes a searchable roll. Most owners never open theirs.Assessed value per square foot: the number that makes comparisons possible Raw assessments cannot be compared. Rates can.

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