Property tax confusion and frustration has been running high in Door County since residents received their 2025 tax bills in December. Most notably, the municipal property value reassessments led to surprising numbers, with some property owners seeing big changes in the amount they owed this year.
These changes came as many Door County municipalities actually had big decreases in their tax rates, called mill rates, from 2024 to 2025. Some went down as much as 50 percent or more. The few municipalities with rate increases showed relatively small jumps, no more than 16 percent.
Yet many people received higher tax bills. If the mill rate goes down, why does one’s tax bill go up? The answer lies in elevated property values and how the municipal mill rate is calculated.
Letha Heaton asked herself this very question when she and her husband, Paul, received their property tax bill in 2025. The Washington Island couple’s property tax increased by about 15 percent, but the town’s mill rate decreased by about 40 percent. Until this year, Letha said she assumed if the mill rate goes down, so would the dollar amount owed.
The couple built a second home on Washington Island in 2014, and the lakefront property on the northwest side of the island is meant to be a “family legacy,” according to Letha. The Heatons spend half the year in their island home, with plans to be there year-round soon. They have no future plans to sell the home, nor do their children, she said.
Barb and Mike O’Connell also own property on Washington Island. Five properties, in fact, and according to Barb, no part of their 2025 tax bill came as a surprise to the couple. Four of the five properties saw a decrease in taxes, and their primary residence saw a slight increase of 4.6 percent, she said.
None of the O’Connells’ properties have waterfront on Lake Michigan. Their primary residence is an older, remodeled farmhouse with little acreage, Barb said. They also own a cabin on Little Lake, with a small amount of access to the inland lake and five acres of woodland; a pole barn used as a metal shop with about five acres; an old, vacant farmhouse that belonged to Mike’s parents; and empty fields adjacent to their primary residence.
The biggest drop in taxes for the O’Connells was on their empty land, Barb said. Taxes decreased on that property by 23 percent.
The Town of Washington performed a reassessment in 2025, in order to get property values in line with the real estate market values, according to Alex McDonald, the town clerk-treasurer.
The O’Connells have been living in their Washington Island home and receiving a property tax bill for almost 50 years, she said, and they are well-versed in the way mill rates and assessments affect their bottom line.
“Every ten years or so, we go through this,” she said. “People get upset.”
What the data shows
In some Door County municipalities, like the Town of Egg Harbor, home values rose more than in other places and produced large mill rate drops. As a result, Egg Harbor’s tax rates went from $1.21 per $1,000 in 2024 to $0.59 in 2025, a drop of 51.2 percent.
Other substantial rate decreases occurred in the Towns of Brussels and Clay Banks. Brussels’ went down almost 40 percent and Clay Banks’ decreased almost 25 percent.
Most increases in tax rates were small, much less than 10 percent.
Why rates changed
Door County mill rate changes are caused mostly by dramatic shifts in assessed values rather than municipal spending.
Looking at their property tax bill, a Door County resident will see several tax amounts separated by county, municipality, school district, technical college and special districts (usually utility or sanitary districts). When combined, they reflect the total rate for the property, and are expressed as dollar amounts per $1,000 of a property’s assessed value.
For example, if a home is valued at $100,000 and the municipal mill rate is $1.00 per $1,000 of value, $100 of the tax bill would go to the municipality. If the school district’s rate is $2.00 per $1,000, another $200 would go to the school district. Together, that’s $300 in taxes — before adding the county, technical college and any special district taxes.
In order to calculate mill rates, municipalities start with the total dollar amount a local government collects in taxes to fund its budget, the levy. The levy is then divided by the sum of all taxable property values – total equalized assessed value – in that jurisdiction, said Ryan Schley, the Door County treasurer.
“Your bill is dependent on the following: your own property’s assessed value, how fast your property’s value rose relative to the total base and how much the levy increased,” Schley explained in an email. “If your home’s assessed value goes up by a lot more than the average increase in the municipality, you can pay more overall even though the tax rate drops.”
This explains why the O’Connells saw only a modest change one way or another in their property taxes this year, and why the Heatons’ taxes increased by 15 percent.
The Heatons’ Washington Island home doubled in value after the town’s reassessment, Letha said. The couple appealed the assessment because it reflected a nonexistent garage on their property and more square footage than their home actually has. The assessment value came down after their appeal, she said. Their property taxes still went up however, because the assessment was still more than the town average.
Each of the five properties owned by the O’Connells only went up a few thousand dollars at most, according to Barb. Assessed value increases similar to the town’s average coupled with a lower mill rate led to lower taxes overall for the couple.
In small towns, the tax base is small. If one or two properties go way up in value after a reassessment, then the total value of all the property in the town—its tax base—goes up noticeably. One marina, condo project or resort expansion could make a big difference.
When the tax base grows, or property values go up, the mill rate per $1,000 of value drops, even if the town has the exact same levy it did the previous year. Most local levies rose very modestly this year, according to Schley.
Loan restructures, property reassessments and levy changes affect several towns
According to Clay Banks Clerk Jessica Bongle, the drop in mill rate was not due to reassessments because the town did not perform any in 2025.
What Clay Banks did do in 2025 was restructure its loan for broadband internet service, Bongle said. The town now owes about $216,000 instead of $296,000 on its loan, which made its debt payment go down.
For those Door County municipalities that did perform assessments, they were following state law that requires Wisconsin municipalities to reassess property to be within 10 percent of the market value at least once every five years. Some do annual assessments to keep up with fluctuations in the market.
The Town of Brussels did have a reassessment in 2025, according to Chairman Joe Wautier. Residential property values were down to 60 percent of the market value, he said, and after reassessment, they are back to 100 percent.
“This lowers the tax (mill) rate charged per $1,000 of value,” he said, “but does increase the total taxes paid on some properties.”
The town office in Brussels received many calls from taxpayers not understanding their bills and the procedure, Wautier added, but after it was all done, the majority understood.
The town electors in Brussels also voted to approve a levy limit increase, reflected in its 2026 budget increase for public safety-related costs.
The Town of Egg Harbor also had a full revaluation done in 2025, according to Clerk-Treasurer Pam Krauel, and revaluation usually results in a mill rate reduction.
“That is the norm,” she said.
Another steep mill rate decrease – almost 44 percent – occurred in the Town of Washington this year. The island also had a full reassessment to get property values in line with market prices in 2025, and many properties increased in value, according to McDonald, the clerk-treasurer.
Like Brussels, Washington Island increased the levy to be collected in 2025. For Washington Island, the increase was 4.7 percent, or $93,279 for a total town levy of about $2 million. The increase was approved by the town electorate in December. The town budgeted to subsidize almost all operations for the Washington Island Mosling Rec Center and allocated more funds for road maintenance, McDonald said.
Island residents, like the Heatons, who see a lower mill rate but owe more in taxes probably had an assessment that may have increased significantly more than average, she added.
Levy limits
If a levy is the total amount in property tax revenue a municipality collects in a given year, a levy limit is the maximum that the municipality is allowed to collect. In Wisconsin, municipalities are limited by state law in the amount they can increase the levy annually.
“This amount (allowed) is generally tied to the growth in new construction and value in that municipality,” Schley said.
If there is little or no new construction in a municipality, the levy can only grow by a small amount, or not at all. Rising market values or increases caused by reassessments do not factor into levy limit increases. However, new homes, additions and new commercial buildings are factored into the allowed limit.
A simplified version of how the state calculates levy limits is to take the value of all new construction and divide it by the total equalized value, or sum of all property. This percentage is how much the municipality is allowed to increase its property tax levy for that year.
If the total property value in a town is $1 billion, and new construction for the year totaled $10 million, then the levy increase is $10 million divided by $1 billion, or a levy increase of 1 percent. If the previous year’s levy was $2 million, then 1 percent of that, or $20,000, is the allowable levy limit increase.
A municipality may increase the levy to the allowed amount, increase it by less, or keep it flat, unless an exception applies. In that case, a municipality can take it to referendum, or town vote, in order to exceed the levy limit.
If property values rise due to reassessment and the levy is capped by the state, then the mill rate per $1,000 falls. This is exactly what happened in many Door County municipalities from 2024 to 2025.
This structure makes it difficult for municipalities to plan for the future, especially with regard to keeping up with road maintenance costs, Brussels’ Wautier said.
Putting it all together
Property tax bills start from the top when municipalities determine how much money they need to operate. This is the levy. Wisconsin law limits the amount the levy can increase annually, based on new construction, not rising property values. Once the levy is set, the mill rate is calculated by dividing the levy by the total value of all taxable property in the municipality.
When reassessments or market changes cause property values to rise sharply, that larger tax base can drive the mill rate down, even if the levy stays the same or increases slightly.
The scenario of mill rates going down while taxes increase for some properties might happen again next year, at least in Clay Banks. The town will perform a reassessment in 2026, according to Bongle, and that may have an effect on tax bills. If individual property values rise faster than the town average, those property owners will see a higher tax bill, even if the rate goes down.
Infrastructure costs for buildings, facilities and road maintenance, public safety and emergency services costs and how much debt a municipality carries are all pressure points that affect municipal budgets and tax rate fluctuations.
Tax bills may continue to be volatile, especially for towns that have not had a reassessment in recent years, and Letha Heaton, the Washington Island property owner, said she is concerned about how it might affect some Door County residents.
While the Heatons are fortunate to be able to absorb their property tax increase this year, she said she worries about her kids being able to afford to keep the family home, and the people living on the island year round who are on fixed incomes.
“I don’t know how they are going to handle that,” she said.