Travis Bunn

Founder, AppealDesk · Published February 27, 2026 · Updated July 27, 2026

How Much Can Property Taxes Increase in Illinois? (PTELL Explained)

Updated July 2026 · 12 min read

Illinois property taxes can increase by much more than 5% per year, even with PTELL. The Property Tax Extension Limitation Law (PTELL) limits how much total revenue taxing districts can collect (5% or CPI, whichever is less), but it does not cap individual property tax bills. Your bill can increase 10%, 20%, or even 50% in a single year due to reassessments, tax burden shifts, and other factors.

This is one of the most misunderstood aspects of Illinois property taxes. Homeowners often assume "5% tax cap" means their bill can't increase more than 5% annually, but that's not how PTELL works. If your property's assessed value increases during a reassessment (quadrennial in most counties, triennial in Cook County), or if your neighborhood appreciates faster than the county average, your bill will increase significantly regardless of PTELL limits.

How Much Can Property Taxes Increase Per Year? PTELL Limits Levies, Not Bills

Here's what you need to know about Illinois property tax increases:

• PTELL limits levy growth to 5% or CPI (whichever is less): This applies to the total amount a taxing district can collect, not individual property bills.
• Individual bills are NOT capped: Your property tax bill can increase by any amount if your assessed value rises during reassessments.
• Reassessments drive volatility: Most Illinois counties reassess all property every four years (the quadrennial cycle); Cook County reassesses every three years on a rolling schedule. Each reassessment resets values to market and can move bills sharply.
• Home rule municipalities are exempt: Cities like Chicago can raise property taxes without PTELL limits.
• Tax burden shifts: Even with PTELL, if your property's value increases faster than your neighbors', you'll pay a larger share of the capped levy.

Translation: PTELL provides modest protection against runaway government spending, but it does NOT protect homeowners from large tax bill increases. If you want to limit your property tax increases in Illinois, appealing your assessment is your most powerful tool.

What Is PTELL? How the Property Tax Extension Limitation Law Works

The Property Tax Extension Limitation Law (PTELL) was enacted in 1991 to limit property tax growth in Illinois. Despite being commonly called a "tax cap," PTELL is actually a levy limit: it restricts how much total revenue taxing districts can collect, not how much individual property owners pay.

How PTELL Limits Work

• Annual levy growth limited to 5% or CPI (whichever is less): Non-home rule taxing districts can only increase their total property tax extension (the total amount billed to all properties) by this amount each year.
• New construction excluded: PTELL allows additional revenue from new construction, additions, and improvements; these don't count toward the 5%/CPI limit.
• Voter-approved increases exempt: Referendums can authorize levy increases beyond PTELL limits (for schools, libraries, parks, etc.).
• Home rule municipalities exempt: Cities like Chicago, Evanston, and other home rule jurisdictions can raise property taxes without PTELL restrictions.

Example of how PTELL works:

• A school district collected $10 million in property taxes in 2025
• The PTELL limiting CPI for levy year 2025 (billed in 2026) is 2.9%, which is less than 5%, so 2.9% is the cap
• The district can collect up to $10,290,000 in 2026 ($10M x 1.029)
• Plus additional revenue from new construction (no limit)
• Plus voter-approved increases (if any)

Why PTELL Doesn't Protect Your Individual Bill

Here's the critical misconception: PTELL limits the total pie, not your slice of it. If the total levy is capped at $10.29 million, but your property's assessed value increases from $300,000 to $400,000 (+33%) during a reassessment, your share of that $10.29 million will increase proportionally, potentially by 33%, not 2.9%.

Real-world scenario:

• Your home was assessed at $300,000 in 2025
• Total county assessed value: $2 billion
• Your share: 0.015% of total assessed value
• School levy (PTELL-capped): $50 million
• Your 2025 school tax: $7,500 (0.015% x $50M)

After a 2026 reassessment:

• Your home reassessed at $390,000 (+30%)
• Total county assessed value: $2.2 billion (+10% average)
• Your new share: 0.0177% of total assessed value (increased because you outpaced the average)
• School levy (PTELL-capped): $51.45 million (+2.9%, the limiting CPI)
• Your 2026 school tax: about $9,120 (+21.6%, roughly $1,620 more)

Despite PTELL limiting levy growth to 2.9%, your individual bill increased about 21.6% because your property's value grew faster than the county average. This is why PTELL doesn't stop large tax increases: it just prevents taxing districts from collecting more total revenue beyond the cap.

How Often Do Property Taxes Go Up in Illinois? Reassessment Cycles Explained

Illinois law (35 ILCS 200) requires a general reassessment of all real property every four years, the quadrennial cycle, in every county except Cook. Cook County reassesses on a rolling triennial (every three years) cycle. These reassessments are the primary reason property tax bills fluctuate dramatically in Illinois, far more than PTELL levy limits.

How Illinois Reassessments Work

• Statewide schedule: Counties outside Cook conduct a general assessment of all properties every four years (assessors may also adjust individual values between general assessment years).
• Market value basis: Assessments are adjusted to reflect current market values, at 33.33% of fair market value statewide (except Cook County, which assesses residential property at 10% under its classification system).
• Winners and losers: Properties that appreciate faster than the county average see tax increases; properties that lag behind see decreases.
• No individual assessment caps: Unlike California or Florida, Illinois has no limit on how much your individual assessment can increase during a reassessment.

Cook County's Rolling Reassessment System

Cook County (Chicago and suburbs) uses a unique system: Instead of reassessing all properties countywide every three years, Cook divides the county into three regions (City of Chicago, North Suburbs, South Suburbs) and reassesses one region per year on a rolling three-year cycle.

Cook County reassessment schedule:

• Year 1: City of Chicago townships reassessed
• Year 2: North and Northwest suburbs reassessed
• Year 3: South and West suburbs reassessed
• Repeat cycle

This means Cook County homeowners face reassessments every three years, but only one-third of the county is reassessed each year, reducing market volatility but still causing significant bill fluctuations for properties in the reassessment year.

What a Reassessment Year Looks Like

The math works the same in any reassessment year, in Chicago or downstate. Suppose a home's assessed value rises 30% in a reassessment while the countywide tax base rises 10%:

• The home's share of the tax base grows: 1.30 divided by 1.10 means its slice of every levy is about 18% larger
• The levies themselves still grow: PTELL-capped districts can add up to the limiting CPI (2.9% for levy year 2025, billed in 2026), and home rule and voter-approved levies can add more
• Result: that homeowner's bill rises roughly 22% even though every PTELL district stayed under its cap

This illustrates the fundamental problem: PTELL controls levies, not individual bills. Reassessments drive tax bill volatility, and PTELL provides zero protection against assessment increases.

Home Rule Municipalities: No PTELL Protection

Illinois home rule municipalities are exempt from PTELL. Under the Illinois Constitution, any municipality over 25,000 residents is automatically home rule, and smaller municipalities can adopt home rule by referendum (voters can also repeal it the same way, so status is worth confirming locally rather than assuming from population). A home rule municipality sets its own levy without the 5%-or-CPI limitation.

Which Illinois Taxing Districts Are Subject to PTELL?

Two conditions have to be met before PTELL binds a district: the district has to sit in a PTELL county, and it has to be non-home-rule. Where both hold, the cap applies broadly:

Subject to PTELL:

• School districts
• Community college districts
• Township governments and road districts
• County governments
• Park districts
• Library districts
• Fire protection districts
• Non-home rule municipalities

Outside the PTELL cap:

• Home rule municipalities entirely, including the City of Chicago, Evanston, Oak Park, Naperville, and Aurora
• Any district in a county that never adopted PTELL
• Voter-approved referendum increases, which sit on top of the capped amount
• Debt service on voter-approved bonds and on bonds predating the county's PTELL adoption (non-referendum debt is generally counted inside the cap, so check the specific levy rather than assuming all bond payments are exempt)
• New construction, additions, and improvements, which add extension room without counting against the limit

In practice, this means Chicago homeowners have no levy-cap protection at all. The city sets its levy through the annual budget and the county clerk computes the rate needed to produce it, so the only restraint on growth is political.

Which Illinois Counties Have PTELL?

PTELL first applied to the five collar counties around Chicago beginning with the 1991 levy year. Cook County was added for the 1994 levy year. Every other county is covered only if its voters approved PTELL in a county-board-initiated referendum, so the law still doesn't reach all of Illinois.

Current PTELL Coverage

Collar counties (subject to PTELL since levy year 1991):

• DuPage County
• Kane County
• Lake County
• McHenry County
• Will County

Other counties with PTELL:

• Cook County (added to PTELL beginning with the 1994 levy year)
• Counties that opted in via county-board-initiated referendum (check with your county clerk)

Counties WITHOUT PTELL:

• Downstate counties whose voters have never been asked, or who voted the referendum down
• Generally the smaller and more rural counties, though there is no population rule; it is purely whether a referendum passed

Do not guess from geography. A substantial number of downstate counties have adopted PTELL at referendum, and a neighboring county may have gone the other way. If you live outside Cook and the collar counties, your local taxing districts may not be subject to PTELL at all, which means levy growth there is limited by other statutory rate ceilings rather than by the 5%-or-CPI formula. Your county clerk can tell you in one phone call whether your county is under PTELL.

PTELL Change for Levy Year 2026: Energy Community Reinvestment Act Abatements

The 104th General Assembly has taken up legislation amending PTELL beginning with levy year 2026. Under the change, a taxing district that grants a property tax abatement under the Energy Community Reinvestment Act has its aggregate extension base recalculated as though the abatement amount had been included in its extension. In plain terms: granting one of these abatements no longer permanently shrinks the district's PTELL base. Because the final status of this amendment was still moving at the time of writing, confirm it against the Illinois General Assembly record or your county clerk before relying on it for a specific levy year.

Why homeowners should care: the aggregate extension base is the starting number that PTELL's 5%-or-CPI limit multiplies against each year. Previously, a district that abated taxes for an energy-community project saw its base, and therefore every future year's cap, ratchet down. With the recalculation, districts can grant those abatements without giving up future levy room. That removes a disincentive to support energy-community redevelopment, but it also means the abatement provides no lasting reduction in what the district can collect from everyone else. If a district in your area has granted an Energy Community Reinvestment Act abatement, check its levy year 2026 extension with the county clerk.

Worked Examples: How Much Can Illinois Property Taxes Increase?

Example 1: A Reassessment Year in a Collar County

• Starting point: a home carries a $100,000 equalized assessed value and an $8,000 tax bill
• Reassessment: the home's value is raised 25%, while the townshipwide average increase is 10%
• Levy growth (PTELL-capped): 2.9%, the limiting CPI for levy year 2025
• New bill: the home's larger share of the base (1.25 over 1.10) times the 2.9% levy growth puts the bill near $9,350, an increase of about 17%

Despite PTELL holding levy growth under 3%, the individual bill rose about 17% because the property outpaced the average. That gap between the levy cap and the bill is the whole story of Illinois reassessment years, and it is also the appeal opportunity: the 25% increase is only as accurate as the mass-appraisal model behind it.

Example 2: A Home Rule City Levy

As a home rule municipality, Chicago is exempt from PTELL, and the arithmetic of that exemption is worth seeing plainly. Consider a home rule city that levied $100 million last year and decides in its budget to levy $110 million this year:

• Levy growth: 10%, set by a council vote rather than by any statutory limit
• What PTELL would have allowed: nothing above the lesser of 5% or the limiting CPI (2.9% for levy year 2025), plus new construction and referendum amounts
• Effect on a property whose assessment did not change: its share of the base is the same, so its city portion rises with the levy, about 10%
• The check on that increase: the budget process and the ballot box, not a cap

This is why home rule status matters more than most homeowners realize. In a PTELL district, the levy line on your bill has a ceiling written into statute. In a home rule city, it does not; the restraint is political rather than legal. Chicago's largest single increase, the $543 million package adopted in the 2015 budget to fund police and fire pensions, is the standard illustration: no PTELL district could have raised its extension by that proportion in one year.

Example 3: A Non-Reassessment Year

In years when your township is not being reassessed and the market is calm, PTELL comes much closer to working the way homeowners assume:

• No general reassessment: your assessed value, and your share of the tax base, holds roughly steady
• Levy growth (PTELL-capped): the limiting CPI, which is 2.9% for levy year 2025 bills payable in 2026
• Individual bill increases: most bills in PTELL districts move only a few percent, close to the levy growth rate

This shows that in non-reassessment years, PTELL can effectively limit tax bill growth for most homeowners. The problem is reassessment years, when individual assessments jump dramatically.

Limitations on Property Tax Assessments: Illinois vs Other States

How does Illinois' PTELL compare to other states' property tax caps?

The pattern in that table is the one that matters: the states with strong individual protection cap the assessment, and Illinois does not. California, Florida, and Texas all limit how far a single property's taxable value can move in a year, which puts a hard ceiling under each owner's bill. Illinois, like New York, limits only what districts can collect in aggregate, and New York's 2% levy cap is actually tighter than PTELL's 5%-or-CPI formula, though PTELL covers only part of the state. Compared with Pennsylvania, which has no statewide assessment cap either, Illinois at least has a levy limit in its most populous counties. Against California's Prop 13 or Florida's Save Our Homes, it offers far less to an individual owner.

Illinois Average Effective Property Tax Rate in 2026

Illinois carries the second-highest effective property tax rate in the nation, behind only New Jersey, a ranking that has held steady across every major study for years. Published estimates of the statewide average effective rate (annual taxes as a share of market value) generally land at around 2% of home value, roughly double the national average. What that means in practice for 2026:

• The effective rate is what matters: it is your actual bill divided by your home's market value, after the assessment ratio, state equalizer, and exemptions are applied
• Rates vary widely by community: south suburban Cook County and parts of the collar counties tend to carry the heaviest effective rates, while many downstate counties run lower
• Your own effective rate is checkable: divide your most recent bill by a realistic market value for your home; if the result is far above 2%, either your local rates are unusually high or your assessment is

Illinois' high property taxes stem from heavy reliance on local property taxes to fund schools, pensions, and municipal services. Weak state funding for schools forces local districts to raise property taxes, and underfunded pensions create additional pressure on municipalities to increase levies.

Are Property Taxes Going Up in Illinois in 2026?

For most homeowners, yes, at least modestly. The PTELL limiting CPI for levy year 2025, the taxes billed and payable in 2026, is 2.9% (the December 2024 year-over-year CPI-U). That means non-home-rule districts in PTELL counties can grow their extensions by up to 2.9%, plus whatever new construction adds and any voter-approved referendum amounts. Home rule cities such as Chicago set their own levies outside PTELL entirely, so their 2026 increases depend on budget decisions, not the cap.

Whether your bill rises 2.9% or far more depends mostly on whether your township is in a reassessment year. If it is, and your value moves up faster than the local average, your increase can be a multiple of the levy growth. That reassessment number is the one worth checking before your appeal window closes.

What Can Illinois Property Owners Do?

Given Illinois' weak protections for individual homeowners, here's how to manage property tax increases:

1. Appeal Your Assessment (Especially During Reassessment Years)

Appealing is your most powerful tool. A successful appeal lowers the assessed value your bill is figured from, and in most counties that correction carries forward until the next general reassessment, so one appeal can pay off across several years of bills.

• Gather recent comparable sales data (adjust for the assessment ratio, 33.33% of market value in most counties)
• Document property issues or defects
• Consider hiring a professional (many work on contingency: no savings, no fee)
• File on time; Illinois deadlines are strict

2. Apply for Homestead Exemptions

Illinois offers several homestead exemptions that reduce your assessed value before taxes are calculated:

• General Homestead Exemption: Reduces equalized assessed value by up to $10,000 in Cook County, $8,000 in counties contiguous to Cook, and $6,000 in all other counties
• Senior Citizens Homestead Exemption: Additional reduction for homeowners 65+
• Senior Citizens Assessment Freeze: Freezes assessed value for seniors meeting income limits
• Disabled Persons' Homestead Exemption: Additional reduction for disabled homeowners
• Veterans' Exemption: Reduction for qualifying veterans

The savings from an exemption is straightforward arithmetic: multiply the equalized assessed value it removes by your composite tax rate. A $10,000 Cook County general homestead reduction against a composite rate of 8% is about $800 off the bill; the same $10,000 against a 12% composite rate is about $1,200. Both figures are on your bill already, so you can run your own number in a minute. Apply with your county assessor; exemptions are not automatic, and a lapsed one is a common reason a bill jumps.

3. Monitor Local Referendums and Vote

PTELL can be bypassed through voter-approved referendums. Pay attention to ballot measures for school bonds, library levies, park district funding, and other tax increases. These referendums can significantly increase your property taxes beyond PTELL limits.

4. Track Reassessment Cycles

Know when your county is scheduled for its next general reassessment (every four years in most counties, every three in Cook). If you're due for reassessment soon:

• Research comparable sales in your neighborhood now
• Document any property issues or defects
• Set aside savings for potential tax increases
• Be prepared to appeal immediately when reassessment notices arrive

5. Consider the Senior Freeze

If you're 65+ and meet the income limit, the Low-Income Senior Citizens Assessment Freeze Homestead Exemption freezes your equalized assessed value at a base-year level, providing protection similar to California's Prop 13 for qualifying seniors. The income limit is set by state statute and applies statewide; it does not vary by county. The limit has been $65,000, and 2025 legislation is reported to raise it to $75,000 beginning with assessment year 2026, with further step-ups in later years. Confirm the current figure with your county assessor or the Illinois Department of Revenue before applying.

One clarification worth making, because it trips people up: the senior freeze freezes your assessed value, not your tax bill. Rates can still rise, and levies still grow, so a frozen homeowner's bill can go up. What the freeze does is spare you every future reassessment increase, and that gap compounds. In year one it may be worth little; after two or three reassessment cycles it is the difference between your frozen equalized assessed value and what your value would otherwise be, multiplied by your composite rate. It is income-limited and seniors-only, but if you qualify, apply as soon as you are eligible, since the base year is set when you first qualify.

The Bigger Picture: Illinois' Property Tax Crisis

Illinois' property tax problems stem from structural issues beyond PTELL:

• Underfunded pensions: Illinois has one of the worst-funded pension systems in the nation, creating massive pressure on local governments to raise property taxes.
• School funding inequity: Illinois ranks near the bottom nationally for state funding of schools, forcing local districts to rely heavily on property taxes.
• Too many taxing districts: Illinois has more units of local government than any other state, a count commonly put near 7,000, and a large share of them levy property taxes. That is why a single Illinois bill lists so many separate line items: school district, community college, township, road district, county, municipality, park, library, fire protection, and often more.
• Political gridlock: Proposals for property tax reform (including assessment caps) have repeatedly failed in Springfield due to concerns about shifting tax burdens or reducing revenue.

Until Illinois addresses these structural issues (pension reform, consolidated taxing districts, or increased state funding for schools), homeowners will continue to face high property taxes with limited protection from PTELL.

Frequently Asked Questions

Can my Illinois property taxes go down?

Yes, if your property's assessed value decreases during a reassessment (due to declining market values, neighborhood conditions, or successful appeal), your tax bill will decrease proportionally. However, this is less common than increases; most Illinois property values have appreciated significantly over the past decade.

What is the Truth in Taxation law in Illinois?

The Truth in Taxation law requires taxing districts to hold public hearings before increasing their levy by more than 5% or the CPI increase (whichever is less). It's a transparency measure, not a cap: districts can still raise taxes after the hearing, but homeowners have the opportunity to voice objections.

How do I calculate my Illinois property tax?

Illinois property tax is calculated as: Market Value × Assessment Ratio × State Equalizer, minus exemptions, then × Total Levy Rate. The assessment ratio is 33.33% of market value in every county except Cook, which assesses residential property at 10% and commercial and industrial property at higher classification ratios. The levy rate is the combined rate of all overlapping taxing districts (schools, township, county, parks, library, etc.).

Does PTELL apply to Cook County?

Yes. Cook County was added to PTELL beginning with the 1994 levy year, so non-home-rule taxing districts in Cook are subject to the same 5%-or-CPI extension limit as the collar counties. The City of Chicago, as a home rule municipality, is exempt and can raise its levy without PTELL limits.

Do property taxes go up every year?

Usually yes, but by different amounts in different years. In PTELL counties, levy growth alone nudges bills up by roughly the limiting CPI (2.9% for 2026 bills) even when your assessment is unchanged. The big jumps come in reassessment years, every four years in most counties and every three in Cook, when your value is reset to market. Non-reassessment years tend to be quiet; reassessment years are when you should scrutinize your bill.

What home improvements increase property taxes in Illinois?

Improvements that add market value or living area generally raise your assessment: additions, finished basements, extra bathrooms, garages, decks, and in-ground pools. Permits are the usual trigger, since assessors review permit filings. Routine maintenance and like-for-like replacement (a new roof, furnace, windows, or siding) generally should not raise your assessment, because it maintains value rather than adding it. Illinois also offers a homestead improvement exemption that can shield value added by improvements to an owner-occupied home for a period of years; ask your county assessor how it applies before you build.

Why did my property taxes double?

A doubled bill almost always traces to one or more of these: a reassessment that sharply raised your value (especially after a recent purchase, since assessors chase sale prices), the loss of an exemption that expired or was never renewed (homestead, senior, or the senior freeze), new voter-approved referendum levies, or the end of a temporary break such as a homestead improvement exemption. Pull this year's bill and compare the assessed value line and the exemption lines against last year's; the cause is usually visible in one of those two places. If it's the assessed value, that is exactly what an appeal challenges.

Can I appeal my property taxes in Illinois every year?

You can file an appeal each year, but most successful appeals occur during or shortly after reassessments, when assessments are most likely to be inaccurate. Appeals based solely on "my taxes are too high" rarely succeed; you need evidence that your assessment is incorrect relative to comparable properties.

Final Thoughts: Appeal Is Your Best Defense

Illinois' PTELL provides modest protection against runaway levy growth, but it does nothing to cap individual property tax bills. If your home appreciates faster than the county average during a reassessment, your bill will increase significantly, regardless of PTELL limits.

A successful appeal lowers the assessed value every future bill is figured from, and in most counties that correction holds until the next general reassessment. With Illinois effective rates running near 2% of home value, even a modest assessment correction compounds into real money over the years you own the home, more than enough to justify the time it takes to appeal.

If your property tax bill increased significantly after a recent reassessment, don't assume it's accurate. Get a professional assessment review, gather comparable sales data, and file an appeal. In Illinois, where PTELL doesn't protect individual bills, appealing is often the only way to keep your property taxes under control.

Figures, deadlines, and program limits in this article are current as of July 2026. Statutes change and county practices vary; confirm specifics with your county assessor, Board of Review, or the Illinois Department of Revenue before acting.