Using Illinois FOIA to get the assessment roll
Assessment records are public. Ask for the electronic file, and cite the subsection that requires it.
Assessment records are public. Where a county publishes little online, the Illinois Freedom of Information Act is how you get the same data anyway — and it is more straightforward than people expect.
What you can ask for
- The assessment roll for a township or the county, as a data file
- Property record cards for specified parcels
- Sales data used in the assessment
- The neighbourhood or valuation-district boundaries the model uses
- Documentation of the assessment methodology
- The comparable properties used in setting a specific value
That last one is the most useful and the least requested. If you are going to argue, knowing what you are arguing against beats guessing.
How to make the request
In writing, to the public body's FOIA officer — the county assessor, the Supervisor of Assessments, or the Board of Review. Be specific about the records and the format.
A request that does not say this can be answered with a PDF of a printout, which is technically compliant and practically useless for building comparables.
Timing and cost
A public body generally has five business days to respond, extendable by five more for defined reasons. A request may be treated differently if it is voluminous or commercial in purpose, so say plainly that yours is for personal, non-commercial use if that is true.
Fees are limited by statute. Electronic records provided electronically typically cost little or nothing; paper copying attracts a per-page charge after an initial allowance.
Refusals and what to do
Assessment data is public and outright refusal is unusual. Where it happens, the body must state the exemption it relies on. You may then seek review by the Public Access Counselor at the Attorney General's office, which is free.
Partial redaction sometimes occurs around personal information, which is generally reasonable and rarely affects what you need — you want assessments, areas and classes, not names.
Whether you actually need it
Often not. Start with the county parcel search and a phone call. FOIA is worth the effort when:
- The county publishes very little online
- You need many parcels — a uniformity case across a subdivision, or a neighbourhood-level analysis
- You want the methodology or the comparables the office actually used
- You are testing whether a whole area is assessed unevenly, which needs bulk data
The tone that gets a useful answer
FOIA is a legal right and it is also a request to a person with other work. A specific, polite request naming the records and the format is answered faster than a broad demand — and asking first whether the data is already published somewhere occasionally saves everybody the process entirely.