How to read your assessment notice
Four numbers and one date matter. The date is the one that ends your options.
Assessment notices are laid out for the office that produced them. Here is what to find.
The deadline
Look for it before anything else. In Illinois the appeal window generally closes 30 days after the township's assessment list is published — not 30 days after the notice reaches you, and not 30 days after you open it. Missing it costs you the entire year. Write it on a calendar now.
The land / improvement split
Your assessment is reported in two parts: land and improvement (the building). They are argued separately and with different evidence. A lot assessed out of line with neighbouring lots is one of the cleanest cases available, and it is invisible if you only read the total.
Prior year versus this year
The notice shows both. A large jump in a quadrennial year is normal; a large jump outside one deserves a question to the assessor.
The property characteristics
Building square footage, year built, lot size, class code. This is the county telling you what it believes about your house. Read every line. A wrong square footage is the single most common winnable error, and you are the only person who will ever notice it.
What is not on it
Your tax bill. The notice shows the assessment; the rate has not been set yet. An assessment increase does not translate one-for-one into a bill increase.