A land value tax is a large structural change. A much smaller idea already fits inside Cook County's existing system, and it is not a land value tax — it leaves the whole tax structure alone and changes one number.
Cook County assesses vacant land at 10% of its market value — the same low rate as a house — while commercial property is assessed at 25%. So holding an empty lot is cheap, even on a busy commercial block. What if a vacant lot were assessed at 20% instead, partway toward the commercial rate — or at the full 25% commercial maximum? Moving a lot from 10% to 20% doubles its taxable value; moving it all the way to 25% multiplies it by two and a half.
There are two ways to do this. In the revenue-neutral version, every taxing district keeps its exact budget: when vacant land's value goes up the rate ticks down a little, so a typical vacant lot pays more while everyone else's bill drops by roughly 0.6%. In the other version, today's rates are left unchanged, so only vacant land pays more and the county simply collects about $125 million more (at 20%) or $188 million (at 25%). Either way, the point is to make sitting on an empty lot more expensive — a small, targeted nudge to build on it — without rebuilding the whole property tax.
Revenue-neutral models of shifting the property tax from total value toward land, built from Cook County Assessor and Clerk data for tax year 2024. Two jurisdictions are covered: the City of Chicago's own levy (~830,000 parcels), and the entire Cook County property tax — every taxing body combined, ~1.77 million parcels. Built end-to-end with the LVTShift pipeline described in Progress & Poverty: “You can now vibe-code a land value tax.”
Today your property tax is based on your whole property — the land plus whatever is built on it. Build an apartment, renovate, or add a story and your assessed value rises, so your tax bill rises. In effect, the current system charges you more for improving your property.
A land value tax shift moves the tax off the building and onto the land underneath it. The government collects the exact same total as before — it is revenue-neutral — but it gets there by charging a high rate on land and a low or zero rate on buildings.
Because the total is fixed, the shift is really a redistribution: your bill rises or falls depending on how much of your property's value is land versus building. A vacant lot or surface parking lot is almost all land, so it pays a lot more. A tall, dense building is mostly building on a small footprint, so it pays less. A typical single-family home lands somewhere in between. The reports below show two versions — a 2.5:1 split-rate (land taxed 2.5 times the building rate, the most Illinois law allows) and a 100% building abatement (buildings taxed nothing, a pure land tax). The goal is to stop penalizing people for building and instead tax land value, which owners did not create — nudging owners to develop and discouraging holding land idle.
Extending the model to all ~1.77M parcels of Cook County (every taxing body's full property tax, tax year 2024). The defensible versions are per taxing body — each of ~900 school/library/park/municipal/county districts shifts its own levy to land within its own boundary, revenue-neutral per district, so every district keeps its funding.