Wisconsin property taxes are paid in arrears, so the 2026 tax bill doesn't arrive until mid-December and isn't due until 2027. At a Madison closing, the seller credits the buyer for the seller's share of this year's taxes, through the day before closing. The buyer then pays the full bill when it comes due, using that credit to cover the seller's part.
By Cait Berry | November 11, 2026
This is the question I get from almost every buyer and seller closing between now and the end of the year. It shows up on Reddit, in first-time buyer forums, and in my inbox, usually phrased something like, "Wait, why am I paying a full year of taxes on a house I just bought?"
You're not, but it can look that way on the closing statement. Here's how it actually works in Madison and Dane County, and why a closing in the last six weeks of the year deserves a little extra attention.
Why Wisconsin taxes look backwards at closing
In Wisconsin, you pay this year's property taxes next year. The tax bill for 2026 covers January 1 through December 31, 2026, but it isn't calculated and mailed until December. According to the Dane County Treasurer, municipalities calculate and mail bills around the third Monday of December.
In the City of Madison, you can pay the full bill by January 31, or split it into four installments due January 31, March 31, May 31, and July 31. The City collects on behalf of Dane County, MATC, the City, and the Madison school district, so it all comes on one bill.
That timing is what makes closings confusing. Whoever owns the home when the bill comes due pays it, even though the seller lived there for most of the year. The proration at closing evens that out.
How the proration is calculated on the WB-11
The WB-11 Residential Offer to Purchase lists real estate taxes among the items prorated at closing, and it says income, taxes, and expenses accrue to the seller through the day before closing. Closing day belongs to the buyer.
The offer then asks you to pick how the tax number is figured. The options on the form are:
- Net general real estate taxes for the preceding year, or the current year if available. This is the default if no box is checked, and it's what most Madison offers use. "Net" means after state tax credits and the lottery credit are deducted.
- Current assessment times current mill rate.
- Sale price times the municipality's area-wide assessment ratio, times the current mill rate.
- Something else the parties write in.
Here's what that looks like on a real number.
A simple example
Say you're buying a $650,000 home on Madison's west side and the seller's 2025 net tax bill was $12,000. You close on December 15, 2026.
- The seller owned the home January 1 through December 14, which is 348 days.
- $12,000 × 348 ÷ 365 = $11,441.
- That $11,441 shows up as a credit to you (and a charge to the seller) on the closing statement.
- In January, you pay the full 2026 bill yourself, or the first installment if you choose the City's payment plan.
The credit isn't a discount. It's the seller's share of a bill you're about to pay. If you spend it on a couch, you'll feel it on January 31.
Why November and December closings are different
Most of the year, everyone is working off last year's bill and nobody knows the real number yet. Late in the year, two things change.
Closing before the new bill is out
If you close in November or early December, the default uses last year's net taxes, because the current bill doesn't exist yet. If this year's bill comes in higher, the buyer is the one who covers the difference, since the seller's credit was based on the smaller number.
This matters more than usual when a home's value or the area's tax rate has moved. The WB-11 itself warns that actual taxes "may be substantially different" from the proration amount, especially with new construction, major remodeling, or an area-wide reassessment, and it encourages buyers to call the local assessor. Madison's 2026 assessments moved a lot of values this year, which I covered in what the 2026 assessment means if you're buying a Madison home.
New construction is the biggest gap. If last year's bill was for a vacant lot or a partially built house in Verona or Sun Prairie, last year's taxes can be a fraction of what the finished home will owe. On a new build, ask your agent to look at a different proration basis, like current assessment times current mill rate.
Closing after the new bill is out
If you close in the second half of December, the actual 2026 bill may already be available. Because the default reads "or the current year if available," the title company uses the real 2026 number, and there's no guessing.
At that point, ask the title company who is paying the bill and when. Sometimes the buyer simply receives the credit and pays in January. Sometimes the bill is handled at closing. Either is fine, as long as everyone knows which one it is before the closing statement is final.
Re-proration: the fix for a guess
Some offers include a re-proration agreement. Under that language, once the actual bill arrives, the buyer sends the seller a copy within 5 days, and the parties settle up the difference within 30 days, based on the real numbers. The WB-11 notes that this is the buyer's and seller's job to complete after closing, not the agents'.
If you're closing in November and taxes are likely to change, this is worth a conversation before you sign the offer. You don't know what you don't know, and a $500 difference is a lot easier to agree on now than to chase in February.
What buyers should check before closing day
- Look for the tax line on your Closing Disclosure. You should see the seller's proration as a credit to you. Ask which year's bill it's based on.
- Ask your lender how your escrow is set up. If your lender is collecting taxes in an escrow account, ask whether they'll pay this first bill or whether you will. A December closing is exactly when this gets missed.
- Plan the cash. If you're paying the bill yourself, the full amount (or the first installment) is due January 31, about six weeks after a mid-December closing.
- Make sure the bill reaches you. The December bill will often be mailed in the seller's name, since they owned the home when it was prepared. Call the City of Madison Treasury if you don't see it by early January.
- Ask a tax pro about year-end timing. Madison counts payments postmarked by December 31 as paid that year. Whether that matters for your return is a question for your tax preparer, not me.
If you want the bigger picture on what the house will cost each month after closing, I broke that down in what owning a Madison home actually costs each month.
What sellers should check before closing day
- Expect the proration as a charge on your settlement statement. It's usually one of the larger line items after your mortgage payoff and commissions, so it's worth seeing in your net sheet early. I walk through the rest of those numbers in closing costs for sellers in Madison.
- Don't pay the 2026 bill yourself in December if you've already closed or are about to. The proration covers your share, and paying the bill too means paying twice, then trying to get it back.
- Leave a forwarding address. If your offer includes re-proration, the buyer needs somewhere to send the bill.
- Know where special assessments land. On the WB-11, special assessments levied, or for work that actually started, before the offer date are the seller's to pay by closing. Later ones belong to the buyer. If your Madison street is on the City's reconstruction list, bring it up early.
Frequently Asked Questions
Are property taxes paid in arrears in Wisconsin? Yes. The tax bill for a given year is mailed in December of that year and paid the following year. In the City of Madison, the bill is due in full by January 31 or in four installments through July 31.
Who pays property taxes the year you buy a house in Madison? Both of you, in proportion to how long you owned it that year. The seller credits the buyer at closing for January 1 through the day before closing, and the buyer pays the full bill when it comes due.
What year's taxes are used for proration at a Wisconsin closing? Unless the offer says otherwise, the WB-11 uses the net general real estate taxes for the preceding year, or the current year's if the bill is available. In a late-December closing, that often means the actual current bill is used.
What happens if the new tax bill is higher than the proration? Without a re-proration agreement, the buyer usually absorbs the difference, since the seller's credit was based on the earlier number. With one, the buyer and seller settle up within 30 days of the buyer receiving the actual bill.
Do I need to pay the December tax bill if I'm selling my Madison home? Generally no, if you close before it's due. Your share is handled as a credit to the buyer at closing, and the buyer pays the bill. Confirm with your title company before you pay anything in December.
The bottom line
Closing on a Madison home in November or December isn't harder, but the tax timing is tighter. The seller's credit covers their share of a bill the buyer pays in January, the WB-11 default uses last year's number until this year's bill exists, and a re-proration agreement is the cleanest fix when taxes are likely to change.
If you're buying this winter and want to see every cost before closing day, my Buyer's Guide walks through the whole process step by step.
Your Madison Insiders
Closing this winter? Know your numbers before closing day.
The Insiders Realty Buyer's Guide walks you through offers, contingencies, and closing costs in Dane County.
About Cait Berry
Cait Berry is the founder and team lead of Insiders Realty with REAL Broker, LLC, serving buyers and sellers across Dane County. A sixth-generation Madisonian and full-time agent since 2012, she helps relocating families, move-up buyers and sellers, and first-time buyers make confident moves in the Madison market. Cait is also a business coach for real estate agents with Tom Ferry International.
This post is general information about Wisconsin tax prorations and the WB-11 Residential Offer to Purchase, not legal, tax, or lending advice. Review your specific contract with your agent, and with your title company, lender, attorney, or tax preparer if you have questions.
