Travis Bunn
Founder, AppealDesk · Published August 19, 2026
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Updated August 2026
Illinois has no ownership-transfer trigger comparable to California's Prop 13 or Michigan's uncapping. Reassessment runs on a fixed area-wide cycle, triennial in Cook County, quadrennial in most of the rest of the state, and inheriting a home does not by itself move that clock. What actually surprises heirs here is that none of the three major homestead exemptions transfer automatically, and losing them can look exactly like a reassessment even though the underlying value never changed.
Cook County's own explanation of the sequence is the clearest description available: fair market value becomes an assessed value at a fixed percentage (10% for residential, 25% for commercial in Cook), the assessed value is multiplied by a state equalization factor to produce the equalized assessed value, exemptions are subtracted from that, and the local tax rate applies to what remains. The equalization factor exists specifically because Cook County sets its residential assessment level below the statewide standard of 33.33% used directly in the rest of Illinois, the multiplier brings Cook's effective level back in line. None of this sequence is triggered by a sale or an inheritance. What triggers a value change is new construction, demolition, a parcel split or merge, or the area's scheduled reassessment year.
Each of Illinois's homestead exemptions handles a change of ownership differently, but the common thread is that a non-spouse heir starts from zero on all three.
The exemption reduces equalized assessed value by up to $10,000 in Cook County, $8,000 in counties contiguous to Cook, and $6,000 elsewhere, the increase in EAV over a 1977 base year, capped at those figures. In Cook County, the statute lets the exemption remain in place for the rest of the sale year after a transfer, then requires the new owner to apply for the following year. In practice, that means an heir who inherits mid-year may see the exemption hold briefly before it disappears the next billing cycle if no one refiles.
Worth up to $8,000 of EAV reduction in Cook and contiguous counties, $5,000 elsewhere, for owner-occupants 65 and older. The statute explicitly extends continuation to a surviving spouse 65 or older who occupies the residence, or lets it continue on a property still owned by the originally-qualified person. It says nothing about a non-spouse heir, a child inheriting from a parent is not covered by that continuation language and has to independently qualify and apply.
This one requires annual reapplication via Form PTAX-340 regardless of circumstances, no automatic renewal for anyone. Current income ceilings are $75,000 for 2026, rising to $77,000 in 2027 and $79,000 in 2028 and after. If the applicant dies, the statute grants continuation only for the taxable year preceding and the year of death, a surviving spouse has to independently qualify after that on their own age, income, and occupancy. Cook County's process for a deceased taxpayer requires an affidavit, a death certificate, both parties' driver's licenses, and, where relevant, Letters of Office or successor-trustee paperwork.
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Illinois abolished its inheritance tax in 1983 and replaced it with an estate tax, filed with the Illinois Attorney General's office, not the Department of Revenue. The exclusion amount has been $4,000,000 for every death on or after January 1, 2013, and that figure has not moved since, it is not indexed for inflation the way the federal exemption is. Above the exclusion, the tax computes by reference to an older, pre-2001 federal state-death-tax-credit table frozen into Illinois law, producing a graduated structure that reaches a top marginal rate in the mid-teens on larger estates. If your family's estate is anywhere near $4,000,000, get the exact current bracket detail from the Attorney General's office rather than relying on a rough estimate.
Illinois statute gives complaint rights broadly to any taxpayer, and the Board of Review complaint statute requires only that the complaint be filed in writing by the complaining party, it does not define that term narrowly or demand proof of full legal title. That said, Cook County's own public materials do not spell out exactly what documentation an heir without completed probate needs to provide in place of full title, an affidavit of heirship, a will, a death certificate, or something else. If you are appealing before Letters of Office are issued, it is worth a direct call to the Board of Review to confirm what they will accept rather than guessing.
The appeal ladder is County Assessor informal review, then Board of Review, then the Property Tax Appeal Board, then Circuit Court, with a statewide statutory window of 30 days from the assessment change notice. Cook County adds its own wrinkle: township filing windows are not set on a fixed annual calendar, each township's roughly 30-day window opens on its own schedule once that township's reassessment work is complete, and missing it means waiting for the next assessment year. Pre-registration is available before a township's window formally opens.
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The single most avoidable mistake in Illinois is assuming a jump in your tax bill after inheriting means the assessment changed. Far more often it means an exemption quietly dropped off because no one refiled in the new owner's name. Re-file every exemption you actually qualify for as soon as the transfer is complete, and treat the assessed value itself as a separate question, one you can still appeal if it is genuinely wrong.
No. Illinois reassesses on a fixed area-wide cycle, triennial in Cook County, quadrennial in most other counties, unrelated to individual ownership changes. What actually changes a bill after inheritance is usually an exemption dropping off, not the underlying assessed value.
No, not automatically for any of the three main exemptions. The General Homestead Exemption may continue through the remainder of the sale year in Cook County before requiring a new application. The Senior Citizens Exemption extends only to a qualifying surviving spouse. The Senior Freeze requires annual reapplication for everyone and continues after a death only through the year of death itself.
Illinois has an estate tax, not an inheritance tax, the inheritance tax was abolished in 1983. The estate tax exclusion has been a fixed $4,000,000 since 2013 and is not adjusted for inflation, and it's filed with the Illinois Attorney General's office rather than the Department of Revenue.
Illinois law gives broad "any taxpayer" standing to file a complaint, but Cook County's own materials don't specify exactly what documentation an heir needs before probate finishes. Call the Board of Review directly to confirm what they'll accept, an affidavit of heirship, a will, or a death certificate, rather than assuming.
Cook County assesses residential property at 10% of fair market value (25% for commercial) rather than the statewide standard of 33.33%, then applies a state equalization multiplier to bring its effective level back in line with the rest of the state. This extra step, plus Cook's own filing windows and triennial cycle, makes the process meaningfully different from most other Illinois counties.