How Are Property Taxes Prorated at Closing in DuPage County? A Buyer and Seller Guide
Updated: 14 hours ago
By John Salidas, Broker | The Salidas Group at @properties Christie's International Real Estate. Research checked November 2, 2026. Property-tax calculations and contract terms are property-specific; this guide is educational and not legal, tax or settlement advice.
A DuPage County buyer may receive a property-tax credit at closing and still be responsible for the next tax bill. A seller may see both a tax payment and a separate tax-proration debit on the settlement statement. Those entries are not necessarily duplicates.
The reason is Illinois's tax cycle: property is assessed in one year and generally billed in the next. At closing, the parties must allocate taxes for periods when the final bill may not yet exist. The signed contract, the parcel's payment history and the closing professionals determine the actual calculation.
The short answer
For an existing home, the seller generally pays outstanding tax bills and gives the buyer a credit for the seller's ownership period before closing, as required by the contract. The buyer generally pays tax bills that come due after closing. The closing credit is how the parties settle the seller's share of a future bill that the buyer will receive.
That general framework comes from the Illinois Department of Revenue's property-tax closing guidance. It also notes that a lender may require the buyer to deposit additional funds into an escrow account for future bills.
Why DuPage taxes are prorated instead of simply paid through closing day
Illinois uses a two-year property-tax cycle. The Illinois Department of Revenue's 2026 property-tax system publication explains that bills are generally prepared in the year after the assessment year and are usually paid in two installments.
For example, a DuPage bill labeled tax year 2025 is payable in 2026. If a home closes during 2026, the parties may need to address a 2025 bill that is already known or partially paid, plus an estimated share of 2026 taxes that will not be billed until 2027.
That is why a settlement statement can contain more than one tax line. One line may pay an existing installment to the county. Another may credit the buyer for the seller's portion of taxes that are not yet billed. Ask the attorney or title company to identify the tax year and ownership period attached to every line.
What a property-tax credit actually does
A tax proration is normally shown as a seller debit and buyer credit. It reduces the seller's net proceeds and reduces the buyer's cash due at closing. It does not pay the future bill to DuPage County on the buyer's behalf unless the settlement statement specifically shows a tax payment.
After closing, the buyer owns the property and is responsible for future bills. If taxes are escrowed with the mortgage payment, the lender may eventually pay the county from that escrow account. The seller's closing credit and the buyer's lender escrow are separate amounts serving different purposes.
Illustrative DuPage proration math
Assume the most recent ascertainable annual tax bill is $10,000 and closing occurs July 1, 2026. For this illustration only, assume the seller's period is January 1 through June 30, or 181 days. The contract and closing team decide whether the closing date belongs to the buyer or seller.
At a 100% estimate, the calculation is $10,000 × 181 ÷ 365 = $4,958.90. That would be the illustrative seller debit and buyer credit for the unbilled period.
Now assume, only for comparison, that the signed contract requires an estimate equal to 105% of the last bill. The estimated annual amount becomes $10,500, and the calculation is $10,500 × 181 ÷ 365 = $5,206.85.
The 105% figure is not a universal DuPage rule and is not a recommendation. Contracts can use different language, estimates or reproration provisions. Never apply a percentage from an online example to a real closing without reading the executed contract.
Why the estimate may differ from the final bill
The current tax year's assessed value, equalization, exemptions, tax rates and levies may produce a final bill that differs from the previous bill. An estimate attempts to allocate that uncertainty, but it cannot make the future bill known.
Continuing the illustration, suppose the eventual annual bill is $10,800. The seller's 181-day share at 100% would be $10,800 × 181 ÷ 365 = $5,355.62. Compared with the earlier $5,206.85 credit, the difference is $148.77.
Whether either party must pay that difference later depends on the contract and any reproration agreement. Some transactions treat the closing calculation as final. Others permit or require reproration after the actual bill is issued. Save the closing statement and contract, and follow the attorney's instructions.
The four tax questions every buyer should ask
1. Which tax years and installments have already been paid? A paid installment should not be charged again. Confirm payment history for the exact permanent parcel number, not merely the street address.
2. What is the source for the estimate? Compare the settlement calculation with the parcel's bill and payment record through the official DuPage County property lookup.
3. Will the exemptions remain the same? A seller's homestead, senior or other exemption may not match the buyer's eligibility. The old bill can therefore be an imperfect estimate of the buyer's future carrying cost.
4. Is lender escrow included in the cash-to-close figure? The tax credit from the seller, prepaid taxes and the lender's initial escrow deposit should be identified separately. A buyer can receive a tax credit and still need substantial escrow funds at closing.
For the broader closing timeline, use the DuPage County homebuyer closing checklist.
The four tax questions every seller should ask
1. Does the net sheet include every unpaid installment? A seller should know whether an existing bill will be paid from proceeds, has already been paid through mortgage escrow or was paid directly.
2. What period does the proration cover? Ask the closing professional to label the assessment year, payable year, day count and contract factor.
3. Is reproration possible after closing? If so, keep the buyer's contact information with the attorney and retain the closing documents. Do not assume the parties will remember the adjustment when the future bill arrives.
4. Could a changed exemption or new assessment affect the estimate? Discuss unusual circumstances early, including new construction, a recent division of land, an exemption change or a large assessment adjustment.
To place the tax lines within the full proceeds calculation, see How Much Does It Cost to Sell a Home in DuPage County in 2026?.
Special issue: new construction and recently improved homes
A new or substantially improved home may not yet have a full tax bill reflecting the completed improvements. Using a vacant-land bill or a partial assessment can materially understate the eventual taxes.
Illinois's official guidance says new-construction taxes are paid according to the contract and notes that the parties often use a reproration agreement after the actual bill is received. Buyers should ask the lender, attorney and builder what assessment information supports the estimate and whether additional reserves are appropriate.
DuPage due dates and the closing calendar
For tax year 2025 payable in 2026, DuPage parcel records show installments due June 1 and September 1, 2026. The state Property Tax Code and Department of Revenue guidance describe June 1 and September 1 as the usual general due dates outside accelerated-billing exceptions.
Those dates matter because a closing shortly before or after an installment can change whether the bill is paid directly at closing, credited between the parties or already satisfied. Always use the current parcel record and tax bill; do not treat this article as a future-year payment calendar.
Property taxes can differ within the same town
A Wheaton, Naperville, Lombard, Elmhurst or Glen Ellyn mailing address does not produce a single townwide tax bill. Taxing districts, assessed value and exemptions are parcel-specific. Two similarly priced homes can have different school, municipal, park, library or fire-district combinations.
For help reading assessments, equalized assessed value and exemptions, review the 2026 DuPage County property-tax guide.
Common mistakes to avoid
Do not compare a seller's tax credit with a buyer's annual tax estimate as if they were the same number. The credit addresses a specific ownership period; the annual estimate addresses a full future year.
Do not assume the mortgage escrow balance transfers to the buyer. The seller's lender handles its escrow account separately, while the buyer's lender establishes a new account under its loan terms.
Do not count an unpaid bill twice. If an installment is paid from sale proceeds, make sure it is not also embedded in a proration for the same period without an appropriate adjustment.
Do not rely on the listing's displayed tax figure alone. Verify the parcel, tax year, exemptions, payment status and whether the bill reflects the current improvements.
Frequently asked questions
Does the seller always pay property taxes through the closing date?
The parties generally allocate taxes according to their ownership periods, but the executed contract controls the day count, estimate and whether later reproration applies. The closing attorney or title company should explain the specific statement.
Why does the buyer get a credit but still pay the next bill?
Because the buyer will own the property when the bill arrives. The credit supplies the seller's estimated share; the buyer then pays the county, directly or through lender escrow.
Can the tax credit be used for the down payment?
The credit affects the overall closing statement, but lender rules determine the required down payment, acceptable funds and escrow deposits. Ask the lender to explain the final cash-to-close calculation.
What if the actual bill is much higher?
Review the contract and reproration language with the attorney. A later adjustment may be available or required, but it should never be assumed from a generic example.
Get a closing estimate tied to the actual parcel
A useful purchase or sale plan starts with the exact DuPage parcel, current bill, payment history, contract language and expected closing date. That produces a much more reliable estimate than a countywide tax percentage.
If you are buying or selling in Wheaton, Naperville, Lombard, Elmhurst, Glen Ellyn or elsewhere in DuPage County, schedule a real estate consultation with John Salidas. I can help organize the property information and coordinate the real estate questions with your lender, attorney and closing team.
John Salidas | The Salidas Group at @properties Christie's International Real Estate | 630.825.9722
Your next step
A tax figure is only useful when it is connected to the actual parcel and your buying or selling plan. John can help you identify records to review and coordinate questions for the assessment office, lender and attorney.
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