On 10,966 Cook County parcels, the homeowner exemption was on the tax year 2022 record, missing in 2023, and back in 2024. On 10,632 of them, 2023 showed no exemption of any kind.
That one-year hole is the pattern to look for in a past-client book. Sales create holes like it: the seller's line stops renewing, and the buyer's starts only once the buyer applies. Rentals, vacancies and estates create them too, and some were fixed later by a Certificate of Error that this data does not show. But where the owner lived there on January 1, 2023, the missing year can still be claimed. The Certificate of Error window currently runs from tax year 2021 through 2025.
Our guide to what's on your client's PIN shows how to check one property. This is the whole-book version.
Quick Answer
Clean your past-client list down to PINs, check each one against the county's exemption records, and set aside entity-owned, sold and opted-out properties. Look for three patterns: a line missing now, a one-year hole, and a line that dropped while another stayed. Contact the rest with a record-backed, specific reason. Then track flags, applications, approvals and refunds as separate numbers.
What the county record shows
Exemption lines that dropped between tax years 2023 and 2024, and how many of those parcels kept another line:
- Homeowner exemption: 35,852 parcels. Mostly sales; set these aside.
- Senior exemption: 14,187 parcels; 1,723 of them still had the homeowner exemption.
- Senior Freeze: 20,332 parcels; 19,074 still had the senior exemption.
- Persons with Disabilities: 1,535 parcels; 687 still had the homeowner exemption.
- Veterans with Disabilities, $2,500 and $5,000 tiers: 258 parcels; 231 still had the homeowner exemption.
The right-hand column is the useful one. When one line drops but another stays, the home is less likely to have changed hands, because a sale interrupts the homeowner line too. That is a screen, not proof.
The Treasurer sees the same problem from the other side. Its State of the Office report dated October 30, 2026 says about 25,000 seniors could save a total of $19 million by applying for exemptions they did not receive.
Step 1: Build the list
- Every closed transaction for the last several years, buy side and sell side
- Convert each address to its 14-digit PIN
- For condos, list the unit PIN and any parking or storage PINs separately. Exemptions go on the unit PIN only; the Assessor says a parking spot cannot receive one
Step 2: Check the record
For each PIN, look at the exemptions on the most recent bills: homeowner, senior, senior freeze, veteran and disability. Look for three things:
- A line missing now that the client would plausibly qualify for.
- A one-year hole, like the 10,966 above. Check recent buyers first, because their first year in the home counts only if they applied.
- A line that dropped while another stayed, like the freeze that disappeared while the senior exemption remained.
A missing line is a flag, not a fact. The property might be a rental, a second home, a home the client has since sold, or one where the client did not qualify that year.
Step 3: Set aside the wrong records
- Sold properties. If your client no longer owns it, the current owner is not your client. Past-year amounts, if any, belong to whoever was eligible then.
- Entity-owned properties. Records held by an LLC or business entity need a different conversation, and many will not qualify.
- Estates and deceased owners. Handle with care, through the family or estate representative.
- Anyone who opted out of contact from you.
Step 4: Prioritize
Rank the remaining flags by:
- Record-backed dollar amount. The exemption's EAV times the property's tax rate, per year. A missing $10,000 homeowner exemption at an illustrative 9% rate is about $900 a year.
- Number of recoverable years. The Certificate of Error window currently covers tax years 2021 through 2025.
- The oldest year at risk. When the window moves forward, the oldest year drops out. A 2021 gap is the most urgent.
Step 5: Make the call
Keep it short, specific and factual:
"I was reviewing county records for clients I've worked with, and your property doesn't show the homeowner exemption for the last two years. If you've lived there as your main home, that may be fixable, and past years can sometimes be refunded. Want me to send you the details?"
What not to say:
- Do not promise a refund. The county decides.
- Do not guess at eligibility. Share the rules and let the client confirm.
- Do not imply you are filing for them unless your brokerage has set that up.
Step 6: Track what actually happened
Count four numbers separately:
- Flags surfaced
- Applications filed
- Applications approved
- Refunds or corrected bills received
Only the last one is money in a client's pocket. Keeping them apart keeps your own reporting honest.
Fair housing and gifts
Base every outreach on the property's record. Run every client against every line. Do not build lists by age or other protected characteristics, and do not turn the senior and freeze figures above into a seniors-only call list. If a message mentions senior relief, describe every exemption and let clients self-select.
If your brokerage pays for exemption filings as a client gift, check your brokerage's gift and disclosure policies first. See the 2026 reassessment notice your clients will misread for more on gift filings.
Where Censum House fits
Censum House's Found-Money checks a pasted client list against Cook County exemption records and surfaces the gaps and the window to claim them. The Past Client Monitor keeps watching the book, and Your ROI tracks which flags turned into outcomes. Censum files the exemptions, and the broker never handles client money. Veterans filings are free on every plan.
The numbers behind this article
Counts are Censum's tabulation of PIN-level exemption amounts, tax years 2022 through 2024, in PTAXSIM, the Cook County Assessor's Office research database built from Clerk and Treasurer records. They count parcels. The Assessor describes PTAXSIM results as not official, and corrections made after the bill may not show.
FAQ
Can my client really get money back?
Sometimes. If they were eligible and the exemption was missing, a Certificate of Error can produce a refund or corrected bill. Approval and payment are separate steps.
What does a one-year hole in the record mean?
That the exemption was on the bill the year before and the year after, but not in between. It can mean a missed application, a sale, a vacancy or a later correction. Check whether your client lived there on January 1 of the missing year.
Do I have to file anything?
No. The homeowner can file directly with the Assessor for free, or use a service.
How many past years can be recovered?
Currently tax years 2021 through 2025, for eligible missing homestead exemptions.
Is this fair-housing safe?
It is when the outreach is based on property records and everyone gets the same information.
Sources
- Cook County Assessor, Certificates of Error
- Cook County Assessor, Homeowner Exemption
- Cook County Treasurer, State of the Office 2027
- Censum tabulation of PIN-level exemption amounts, tax years 2022-2024, from PTAXSIM (Cook County Assessor's Office, built from Clerk and Treasurer records), run November 7, 2026; parcel counts.
Sources accessed November 7, 2026.
Next step
Paste your past-client list and see which homes may be missing an exemption. Run Found-Money on your book
Censum LLC is a data and analytics company, not a law firm and not a tax advisor. Censum is independent and is not affiliated with Cook County or any government agency.