"Building a Home on Wisconsin Farmland: Who Pays the Use-Value Conversion Charge, and How Much Is It?"

The corn stubble runs right up to the township road, and the spot you have in mind for the house is the rise near the mailbox, where the morning light comes across the field. The listing for these fourteen acres in Wisconsin shows a property tax bill that looks almost too small, and one line near the bottom reads "use-value assessed." Your agent mentioned there might be a conversion charge if you build. Nobody has put a number on it yet.

When you build a home on Wisconsin land assessed as farmland, the county charges a one-time use-value conversion charge on the acres that change use. The bill goes to whoever owns the land when the use changes, which is you if you build after you close. The Wisconsin Department of Revenue publishes the per-acre figure for every county each January, so you can price it before you buy.

I'm Jeff Moran, a mortgage broker in Bluffton, South Carolina, originating since 1996, licensed in fifteen states, including Wisconsin, NMLS #483943, through C2 Financial Corporation. A land purchase that turns into a home touches your tax figure, your escrow account and your construction plans, so I like to work this out with you before the offer goes in.

How Wisconsin assesses farmland

Wisconsin values agricultural land on what it can earn from farming instead of what it would sell for on the open market. Wisconsin's assessment statute, section 70.32(2r) sets that standard, and the Department of Revenue calls the result use value. The gap between use value and what the land would sell for is the reason the seller's tax bill looks so modest.

The assessment follows the use of the land. The statute's definition of agricultural land leaves out the buildings and the land they need, which is why a working farm's bill can have more than one class on it.

What triggers the Wisconsin conversion charge?

The charge comes from a change in how the land is used, so buying the land or dividing it does not bring one on its own. The Department of Revenue's conversion charge FAQ says the charge is based on a change of use rather than a change of classification. It also says a parcel that is split off and still farmed carries no charge until its use changes.

The Department of Revenue lists the changes that bring the charge: agricultural land turned to residential, commercial or manufacturing use, or land that becomes tax-exempt and is no longer farmed. As Outagamie County's treasurer puts it, a move from agricultural to undeveloped, agricultural forest, productive forest or the class Wisconsin calls "other" brings no charge.

That last class matters if the land will stay a working farm. Wisconsin defines "other" as the buildings and improvements on a farm, including a home for the farm operator's spouse, children, parents or grandparents, and the land those buildings need. The Department of Revenue's 2026 Agricultural Assessment Guide has a section on the class. If a farm home is your plan, please ask the municipal assessor how your homesite would be classed before you settle on where the house goes.

If you are building a home and letting a neighbor keep farming the fields, the homesite usually becomes residential, and those are the acres the charge applies to.

Who pays the use-value conversion charge when you buy and build?

The owner at the time the use changes pays it. The Department of Revenue's conversion charge notice says the owner of the land when it changed use is responsible. So if the seller converts the land before the sale, the seller pays, and if you convert it after the sale, you pay. Fond du Lac County's treasurer says the same thing from the billing side, since the bill goes to the person who owned the property at the time of the conversion.

So if you close in the spring and break ground in the summer, the charge is yours. It is one bill, figured per acre, and it does not reach back over the seller's years of lower taxes.

The timing runs about a year behind the change. Wisconsin's assessment roll, the municipality's yearly list of how each property is classed and valued, is dated January 1. The Department of Revenue's January 2026 notice to assessors applies the 2026 charges to changes that happened during 2025 and show up on the January 1, 2026 assessment roll. The county treasurer cannot bill until the new class is on the roll and the Board of Review, the local panel that hears objections to assessments, has finished, which gives you a chance to appeal the classification first.

Once the bill is issued, it is due within 30 days. Under Wis. Stat. § 74.485, a late payment adds interest of 1 percent a month. An unpaid charge can be collected as a special charge on the property tax bill, and Fond du Lac County adds it to the next one.

The per-acre formula and the county table

The statute starts with two county averages: what an acre of agricultural land sells for, and what an acre is assessed at for farming. The difference between those two figures is multiplied by a percentage that depends on how many acres change use:

• Less than 10 acres: 10 percent of the difference.
• 10 to 30 acres: 7.5 percent.
• More than 30 acres: 5 percent.

That result is the charge per acre, and it is multiplied by the acres that changed use. The Department of Revenue's FAQ adds two details. The acre count is the total converted by the same owner in the same municipality. And if the charge works out to less than $25 an acre, no charge is due.

A homesite of two or three acres falls in the 10 percent tier, which is the one to look up first.

Finding the per-acre amount before you make an offer

You do not have to work the formula yourself. The Department of Revenue posts its use-value charge report for converting agricultural land every January, with one set of per-acre figures for each county.

County treasurers publish their own figures as well. Dane County's treasurer lists the 2026 charges for land converted during 2025 at $1,329 an acre for less than 10 acres and $997 an acre for 10 to 30 acres. Outagamie County lists $949, $712 and $475 for its three tiers in the same year. Those are one year's numbers for two counties. The figures change every January, so please look up the current table for the county your land is in.

The Department of Revenue also publishes an agricultural use-value conversion charge worksheet for estimating the charge. Its instructions say it is meant for the owner at the time of the change and for a buyer where a sale is taking place, which describes you.

To get a number you can plan around, you'll want four things:

1. The county the land is in, and the current Department of Revenue figure for that county.
2. How many acres you expect the homesite to take once the driveway, well, septic and yard are counted.
3. The tier those acres fall in, which for most single homesites is less than 10 acres.
4. A confirmation from the municipal assessor of how the land is classed now and how the homesite would be classed after you build.

The conversion charge, your property tax and your mortgage

The lender qualifies you on a property tax figure it can document. On land assessed as farmland, the current bill is small, and that is the figure in front of everyone while you are buying the land.

Two separate things change after you build. The first is the conversion charge, a one-time bill that arrives the year after the change. Because it is a one-time charge billed by the county treasurer, please ask your servicer, the company you send your mortgage payment to, ahead of time whether it expects you to pay it directly. The second is the yearly tax. Once the homesite and the new home are on the roll as residential, the yearly bill rises, and your escrow account adjusts at its next analysis. How an escrow account handles taxes and insurance covers the cushion and the yearly review.

Once the new home is your primary residence on January 1, you may also be able to claim the credit described in keeping the Wisconsin lottery and gaming credit on your tax bill.

If you are financing the build, how a construction-to-permanent mortgage works walks through the loan side, and a land and construction plan is something I would rather talk through with you on the phone than describe in general terms. For a home that is already standing on acreage, buying a home on acreage covers how the appraisal treats the land and the outbuildings.

Your list before you buy the land

I would go through these with you in this order.

1. Please ask the municipal assessor how the land is classed today, on how many acres, and whether any part of it changed use earlier this year while the seller owned it.
2. You'll want to decide where the homesite goes and roughly how many acres it will take, because those acres are what the charge is figured on.
3. Please look up your county's current per-acre figure in the Department of Revenue's January report or on the county treasurer's page, and run the estimate on the state's worksheet.
4. If the seller has already started a change in use, such as building or clearing for a non-farm purpose, I would ask your attorney or your agent to address in the offer who pays that charge.
5. Please put the estimated charge into your construction budget for the year after you build, alongside the higher yearly tax on the finished home.
6. If the assessor sends you a notice that your land's class or value has changed, you'll want to read it right away. The Board of Review meets before the conversion charge is billed, and it is the place to raise a disagreement.

Three easy mistakes on Wisconsin farmland

The first is budgeting off the seller's tax bill. That bill reflects use value on cropland, and the year after your home goes up, the homesite is taxed as residential.

The second is assuming the charge comes at closing. Buying the land does not trigger it, and neither does splitting a lot from a farmed parcel. The bill comes after the change in use reaches the assessment roll.

The third is using an old figure. The per-acre amounts change every January and differ from county to county.

An example with made-up numbers

The numbers below are made up to show how the charge works. They are not a real property, a real county figure or an estimate for any county.

You buy fourteen acres of cropland in April. The land is use-value assessed, and you plan to build on two acres near the road while a neighbor keeps farming the other twelve. You start building in June. That June change makes you the owner at the time of conversion.

On the next January 1 assessment roll, the assessor reclassifies your two acres as residential. After the Board of Review finishes, the county treasurer bills you using that year's figure for land converted in the prior year. Say the county's figure for less than 10 acres is $1,150 an acre:

Acres converted                         2
Per-acre charge, under 10 acres    x $1,150
                                   --------
Conversion charge                    $2,300

The bill is due within 30 days of the notice. The other twelve acres stay assessed as farmland as long as they are still farmed. Your yearly tax on the two-acre homesite and the new home is figured separately, at residential value.

Your next step

If you are weighing land in Wisconsin and the home you will build on it, a Wisconsin pre-approval is what stands behind your offer. The Wisconsin mortgage page covers how closings work here, from the owner's title policy to the spouse signature rule. You can also see pricing for a home purchase on your own, with no credit pull. Choose a rate option that works best for you, and know that the selection can change as the file comes together. If you would rather talk through the land, the conversion charge and the build before you make an offer, you are welcome to call me.

Nothing here is a loan approval, a denial or a commitment to lend, and it is not tax or legal advice. The municipal assessor decides how land is classed, and the county treasurer issues the conversion charge, so please confirm your own figures with both.

Common questions

Does buying Wisconsin farmland trigger the use-value conversion charge?

No. The charge is triggered by a change in how the land is used, such as building a home on it, and not by the sale. The Department of Revenue's FAQ says the charge is based on a change of use, and a parcel split off from a farm that is still farmed carries no charge until its use changes.

Who pays the conversion charge when farmland is sold in Wisconsin?

The owner at the time the use changes. If the seller converts the land before the sale, the seller pays. If you convert it after you buy, for example by building a home, you pay. The county treasurer sends the bill to whoever owned the property when the conversion happened.

How much is the Wisconsin conversion charge per acre?

It depends on the county and on how many acres change use. The Department of Revenue posts each county's per-acre figures every January. Dane County and other county treasurers post the same table on their own pages, and the example above shows how the figure turns into one bill. A charge that works out very small per acre is not billed at all.

When is the conversion charge billed?

The year after the change. Charges apply to changes in use that show up on the January 1 assessment roll, and the county treasurer bills them after the Board of Review finishes. The bill is due within 30 days, and a late payment adds interest of 1 percent a month under Wis. Stat. § 74.485.

Does building a farmhouse on Wisconsin farmland bring a conversion charge?

It can depend on who will live there. Wisconsin's "other" class includes the buildings on a farm, among them a home for the farm operator's spouse, children, parents or grandparents, and a change to "other" carries no charge. A home on land that is not part of a farm operation is usually residential. The municipal assessor decides the class.

Where do I find my county's conversion charge figure?

On the Wisconsin Department of Revenue's report titled Use-Value Charge for Converting Agricultural Land, posted each January, and on many county treasurers' websites. The department's conversion charge worksheet lets you estimate the amount for the acres you plan to convert before you buy.