ParcelProof

Blog · Basics · 2026-08-05 · 2 min read

Land and building are assessed separately, and only one may be wrong

Splitting the assessment splits the argument, and the land half is usually easier to win.

Your assessment is two numbers, not one. The county values the land and the building separately, adds them together, and prints the total. Most people only look at the total, and in doing so miss which half is actually wrong.

Why they are separate

Land and buildings behave differently. Land value is driven by location, lot size, shape, zoning and access — and it does not depreciate. A building depreciates, can be improved, can burn down, and is valued on its size, age, quality and condition.

Assessment models treat them as separate problems, which means they can be separately wrong.

Which one is wrong changes your argument

SymptomLikely problemArgument
Land value far above similar-sized nearby lotsLot size, shape or zoning on file is wrongCorrect the record
Improvement value high per square foot vs neighboursBuilding over-assessedUniformity
Total looks fine, improvement looks high, land lowSplit is wrong, total is rightUsually not worth appealing
Improvement value on a demolished buildingRecord not updatedCorrect the record

The third row deserves attention

If the split is wrong but the total is right, you generally have no financial claim — your bill is driven by the total. It is worth knowing about anyway, because it will distort any uniformity comparison you run, in both directions. An improvement figure inflated at the expense of land makes you look over-assessed per square foot when your total is fine.

This is one reason to sanity-check your land value against neighbouring lots before building a uniformity case on the improvement figure.

The land value check

Land is usually assessed on a rate per square foot or per acre within a neighbourhood, sometimes with adjustments for frontage, depth or an awkward shape. So the check is straightforward: divide your land assessed value by your lot area, and compare against neighbouring parcels.

Reasons a land figure is genuinely wrong:

  • The recorded lot size does not match the plat or survey.
  • The parcel is unbuildable in part — an easement, a ravine, a wetland, a floodway.
  • It was split or consolidated and the record was not updated.
  • Zoning changed in a way that reduced what can be built.

The improvement value check

Divide improvement assessed value by the building's floor area, and compare against comparable properties. This is the uniformity comparison, and it is why the split matters — the comparison runs on the improvement figure alone.

Reasons an improvement figure is genuinely wrong:

  • The floor area on file is larger than the building.
  • A basement is recorded as finished and is not.
  • A structure that has been demolished is still on the record.
  • Quality or condition is graded above what the building actually is.

The practical sequence

  1. Find both figures on your notice or parcel page.
  2. Land ÷ lot area, compared against neighbouring lots.
  3. Improvement ÷ floor area, compared against comparable buildings.
  4. Whichever is out of line is your argument. If both are, say so separately — they are different corrections with different evidence, and merging them into one complaint about the total makes both harder to grant.
This is general information about how Illinois assessments and appeals work. It is not legal advice, not an appraisal, and not a prediction about your case. Deadlines and rules differ by county — check yours with your Board of Review.

Check your own assessment free →

More on Basics

← Your PIN, and how to read it · Uniformity: the argument that does not need an appraisal →