On a $400,000 purchase in Lake County, IL, property tax comes to about $10,720 a year — roughly $893 a month — at this county's effective rate of 2.68%.
$
Effective rate 2.68% = this county's median owner-occupied tax bill ($8,609, ACS 2022 5-year estimate) divided by the typical home value at the time ($321,200, Zillow, 2022-12-31). Exemptions the seller holds — homestead, senior, veteran — usually do not transfer with the deed, so a new purchase can run above this figure. The county assessor sets the assessed value; this is an estimate, not a quote.
If you pay late
Illinois statute adds a 1.5% penalty per month on an unpaid installment, increasing by another 1.5% for each month the balance remains unpaid.
Calendar tax year billed in arrears: one bill with both stubs mails the first part of May, with installments in early June and early September. If a due date lands on a weekend or public holiday, most counties move it to the next business day — check the county's own notice before relying on the shift.
By post: mail a cheque to the treasurer's office; the postmark date usually counts, not the arrival date.
In person: the treasurer's office during business hours; bring your bill or parcel number.
Mortgage escrow: if your taxes are escrowed, the servicer pays — you still owe the difference if your escrow is short.
Common questions
When are property taxes due in Lake County, IL?
1st installment (2026 tax year): June 1, 2027. 2nd installment (2026 tax year): September 1, 2027.
What happens if I pay late in Lake County?
Illinois statute adds a 1.5% penalty per month on an unpaid installment, increasing by another 1.5% for each month the balance remains unpaid.
How do I pay Lake County property tax?
Pay online through www.lakecountyil.gov, the county's own payment portal, or by post or in person at the treasurer's office.
Is the Lake County deadline the same every year?
Calendar tax year billed in arrears: one bill with both stubs mails the first part of May, with installments in early June and early September. Counties shift dates when billing is delayed, so confirm against the county source linked on this page.
How much is property tax on a $400,000 house in Lake County, IL?
About $10,720 a year, or $893 a month, at this county's effective rate of 2.68%. That rate is the county's median owner-occupied tax bill ($8,609) divided by the typical home value ($321,200). A seller's homestead or senior exemption usually does not transfer, so a new purchase can cost more.
What if I can't pay in full?
Most counties offer instalment plans or partial payment — ask the treasurer before the due date, not after. Once the bill is delinquent the options shrink and the fees start.
Does a late payment affect my mortgage?
Unpaid property tax is a lien on the property in most states, which your servicer may pay and then bill you for, with fees. It does not disappear.
Ad slot · responsivereserved — add your AdSense ID in ads.js
CountyTaxDates is an independent reference and is not a government agency. Deadlines change and exceptions apply — always confirm with your county treasurer using the official link on this page. Nothing here is tax, legal or financial advice.