March 8, 2026
Studies consistently show that a significant percentage of Illinois properties are overassessed — meaning homeowners are paying more property tax than the law requires. Are you one of them?
In Illinois, your property tax is based on your assessed value. For residential properties:
If your county assessor has valued your home higher than comparable homes in your area, you're paying too much.
Look up what similar homes in your neighborhood have sold for recently. If you can find 3–5 homes that are comparable to yours (similar square footage, age, condition, lot size) that sold for less than what your assessment implies, you're likely overassessed.
For example: If your home is assessed at $300,000 in Cook County (implying a market value of $3,000,000 — which seems high), something is off. The math should work.
If your assessment jumped 15–25% or more in a single year and you didn't renovate, add square footage, or do anything to substantially improve the property, that's a red flag worth investigating.
If you bought your home recently and the assessor's implied market value is higher than what you actually paid — in an arm's-length transaction — you have strong grounds for an appeal.
You can look up your neighbors' assessments on your county assessor's website. If homes that are clearly similar to yours — same street, similar size — are assessed lower, that's called assessment uniformity, and it's a legitimate appeal argument even if your absolute value seems reasonable.
File an appeal. The process is simpler than most people think, and you don't need a lawyer. Overtaxed IL does it for you — we identify the comps, build your case, and file on your behalf. Most appeals take just minutes to start.