Property taxes are one of the largest expenses on any Cook County apartment building — and when the county reassesses, a higher tax bill quietly eats into your net operating income. Since value is NOI divided by cap rate, that reassessment can lower what your building is worth without a single thing changing about the building itself. Here's what owners need to know.
How Cook County reassessment works
Cook County reassesses property on a triennial (every three years) cycle by region. When your area comes up, the Assessor sets a new assessed value that drives your tax bill for the next cycle. For income property, a big jump can meaningfully raise your single largest controllable expense.
Why a higher assessment cuts your value
Walk the math: higher taxes mean lower NOI, and lower NOI at the same cap rate means a lower price. A few thousand dollars of extra annual taxes, capitalized at a market cap rate, can knock tens of thousands off your building's value. It's one of the most underappreciated levers in multifamily — see how valuation works for the full formula.
Reading your assessment notice
When your reassessment notice arrives, don't just file it. Check the assessed value against comparable buildings and against what your building could actually sell for. An over-assessment is appealable — but there are deadlines.
Appeals: process and deadlines
- ✓You can appeal to the Assessor and, separately, to the Board of Review.
- ✓Each has a filing window — miss it and you wait for the next cycle.
- ✓Strong appeals use evidence: comparable assessments, recent sale prices, and income data.
How buyers underwrite future tax increases
Sophisticated buyers don't use your current tax bill — they model what taxes will be after they buy, including any looming reassessment. If your building is due to reset, buyers price that in, which affects your sale price. Getting ahead of it protects your value when you go to sell.
Cook vs. DuPage tax dynamics
Tax treatment differs across county lines, which is part of why buyers weigh location so heavily — a topic we dig into in DuPage vs. Will vs. the City.
Frequently Asked Questions
When is my building reassessed?
Cook County works on a three-year cycle by region. Your notice will tell you when your area is up; we can also help you check.
Can I appeal my apartment building's assessment?
Yes — you can appeal to the Assessor and the Board of Review within their filing windows, using comparable and income evidence.
How much do taxes affect a building's price?
Directly and significantly. Because taxes reduce NOI, and value is NOI divided by cap rate, a tax increase capitalizes into a real reduction in value.
Do buyers factor in tax hikes when they offer?
Experienced buyers underwrite post-sale taxes, including expected reassessments — so an unaddressed increase can lower your offers.
Concerned about how taxes affect your building's worth? Contact us or call (630) 895-7989. *(We're brokers, not tax advisors — consult a property-tax attorney for appeals.)*