The deadline is the most common reason people lose their appeal
Property tax appeal windows are short, staggered by township, and absolutely unforgiving. How the calendar works in Illinois and Connecticut, and how to never miss it again.
Of all the ways to lose a property tax appeal, the most common has nothing to do with the strength of your case. Filing after the window closed ends the matter regardless of what your evidence shows.
Assessment deadlines are statutory. Unlike almost everything else in this process, there is no discretion, no appeal against the refusal, and no good-cause exception. The evidence is simply never read.
Why the calendar is confusing
Three features of the system combine to catch people out.
The window is short. Typically 30 days from the date the assessment notice is published — not from the date you opened the envelope.
It is staggered. In Cook County each of the 38 townships opens and closes on its own schedule across the year. Your neighbour two towns over has a completely different date, and their advice about "when appeals are due" is wrong for you.
There is more than one window. The Assessor and the Board of Review are separate bodies with separate deadlines. Missing the Assessor does not end your year — the Board opens later, and is a genuine second chance most people do not know exists.
Illinois
| Stage | Window | What it costs |
|---|---|---|
| Assessor | ~30 days from township publication | Free; cannot raise your assessment |
| Board of Review | Separate later window, also ~30 days | Free; can raise, though rarely does residentially |
| PTAB / Circuit Court | 30 days from Board decision | Formal; usually worth counsel |
Outside Cook County the townships are fewer but the principle is identical: publication date, thirty days, then the Board.
Connecticut
Connecticut runs on a fixed statutory calendar rather than a staggered one, which is simpler but leaves an even narrower window.
Assessments are published by the end of January. Appeals to the Board of Assessment Appeals must generally be filed by 20 February, with hearings in March. Miss February and the assessment stands for the year — and because Connecticut revalues on a five-year cycle, that assessment may be the basis of your bill for some time.
What the staggering does to you
Cook County's township schedule is the single biggest source of missed deadlines we see, because it defeats every normal way of remembering a date. There is no annual "appeal season" to be aware of. Your township's window may open in March one year and be quite differently placed the next as reassessment groups rotate.
How to never miss it
Find your township. It is on your tax bill and your assessment notice, and it is the only thing that determines your dates. Not your city, not your ZIP code.
Check the assessor's published schedule. Every county office publishes the current year's township calendar. Look it up once a year rather than waiting for post.
Set the reminder for the opening, not the closing. A reminder three days before the deadline is a reminder that you have run out of time. Assembling comparables and requesting a record card takes longer than an evening if any document has to be requested.
Do the analysis before the window opens. Nothing in the preparation depends on the window being open. You can pull comparables, check your record card and confirm your exemptions at any point in the year, and then file on day one.
Note the Board of Review date separately. It is a different deadline for a different body, and it is the safety net if the first one is missed.
If you have already missed it
Two things are still open to you.
The Board of Review, if only the Assessor's window has closed. This is a full hearing on the merits, not a lesser process.
Exemptions and record corrections, which are not appeals and generally do not run on the appeal calendar. An unclaimed homestead exemption can often be applied for outside the appeal window, and several jurisdictions allow retroactive claims for prior years. A factual error in the record card can be raised with the assessor's office at any time — and, being permanent, is worth more than the appeal you missed.
Missing the deadline costs you one year of one argument. It does not cost you the exemption, the correction, or next year.