Ozaukee County property tax records are public and free to search online through the county’s Land Records portal at ascent.co.ozaukee.wi.us. The portal shows assessed values, tax amounts, credits applied, and payment history for every parcel in the county. Anyone can look, whether or not you own property in Wisconsin.
How to Search the Records Online
The Ozaukee County Land Records System is the primary tool. You can search three ways: by parcel number (sometimes called a tax key), by property address, or by owner name.
Parcel numbers follow a set format — a two-digit municipal code, then groups of digits separated by hyphens and a decimal point. The Village of Bayside uses a variant with an extra segment. If you have any prior tax bill or assessment notice for the property, the parcel number is printed on it.
One boundary worth noting: the Land Records portal is for tax and assessment data. If you need recorded documents like deeds, mortgages, or liens, those live with the Register of Deeds on separate platforms (Tapestry EON for occasional users, Laredo Anywhere for daily professional access), with records searchable back to 1894 and images from 1835 forward.
What the Record Shows
A tax record isn’t a single number. Several values sit alongside each other and each does a different job.
The assessed value is the local assessor’s estimate of the property’s worth. It determines how the municipal tax burden is divided among properties in your town or city. The fair market value is what the property would likely sell for on the open market. Wisconsin assessors aim to match the two, but they can drift apart between reassessment years.
A third figure, the equalized value, is set by the Wisconsin Department of Revenue and certified every August 15. It’s the state’s independent estimate of total taxable property in each municipality, and it governs how county and school district taxes are split among municipalities. Without it, a local assessor could shift the county tax load onto neighboring towns by undervaluing property at home.
Your bill itself reflects levies from multiple jurisdictions stacked together: the county, your municipality, your school district, and Milwaukee Area Technical College. Properties inside a lake district or sanitary district will see an extra line. The mill rate combines all of them, expressed as tax per $1,000 of assessed value. On a $300,000 assessed property with a combined rate of $18 per $1,000, gross tax before credits comes to $5,400.
Credits to Check For on Your Bill
Two state-funded credits reduce most Ozaukee County bills directly, and it’s worth confirming both are present when you pull your record.
The Lottery and Gaming Credit applies only to primary residences. You must be a Wisconsin resident who owns the home and uses it as your principal dwelling as of January 1 of the tax year. It requires an application on a Department of Revenue form. If you’ve recently moved or bought a home, this is the credit that most often goes missing.
The First Dollar Credit is automatic. Every taxable parcel in Wisconsin with a building or other real property improvement receives it, whether or not the owner lives there. Rentals, commercial buildings, and vacation homes all qualify, and no application is needed.
How and Where to Pay
Payments in Ozaukee County are split between your municipal treasurer and the county treasurer depending on which installment you’re paying.
Most municipalities use a two-installment schedule:
- First installment: due January 31, paid to your municipal treasurer.
- Second installment: due July 31, paid to the Ozaukee County treasurer.
The Village of Bayside and both the Town and Village of Grafton use three installments instead, all paid to the municipal treasurer, due January 31, March 31, and May 31.
If the total tax on your parcel is under $100, installments aren’t available and the full amount is due January 31.
The county accepts online payments through instructions on the Treasurer’s website, has an after-hours drop box east of the Main Street entrance, and takes payments in person at 121 W. Main St., Room 107, Port Washington, WI 53074. If you mail your payment, the postmark date is what counts. Have the post office hand-stamp the envelope rather than trusting a bank bill-pay service, which often mails from out of state without a postmark.
What Happens If You Pay Late
Missing an installment costs more than a late fee. Under Wisconsin law, missing any single installment cancels your right to pay in installments and makes the full remaining tax due immediately.
Delinquent taxes accrue interest at 1% per month, calculated retroactively from February 1. County boards may add up to 0.5% per month in penalties on top of that, for a combined charge of as much as 1.5% per month. Because the clock runs from February 1 regardless of when the missed installment was actually due, a payment only a few weeks late in August can already carry seven months of charges, or roughly 10.5% of the unpaid balance.
Delinquent real property taxes still unpaid past July 31 transfer to the county treasurer for collection with all accumulated interest and penalties. Continued nonpayment can produce a tax lien and eventually loss of the property through a tax deed.
How to Challenge Your Assessment
If the assessed value on your record looks too high, Wisconsin gives you two openings to push back, one informal and one formal.
Open Book
Open Book runs from late May through mid-June in most municipalities. The full assessment roll is open for inspection, and you can meet informally with the local assessor to talk through your property’s value. If the assessor agrees, they can correct the roll on the spot. No forms, no sworn testimony. The Department of Revenue publishes an annual calendar with each municipality’s Open Book dates.
Board of Review
If Open Book doesn’t resolve it, the Board of Review is the formal step. The board meets during a 45-day window beginning the fourth Monday of April, but no sooner than seven days after the assessment roll closes for examination. It hears sworn testimony about property values only. It does not hear complaints about the dollar amount of your tax bill or questions about exemptions.
To appear, give the clerk notice at least 48 hours before the first meeting and file a written objection on Form PA-115A. The form asks for your parcel number, the assessed value you’re contesting, your own estimate of value, and the evidence supporting it. The strongest evidence is a recent arm’s-length sale of the property itself. Comparable sales of similar nearby properties come next. Appraisals, income data, and construction cost figures can also support your case.
You can testify by telephone or submit a sworn written statement if you can’t attend in person, but the notice and objection form still have to be filed on time. This step matters beyond the board itself: Wisconsin law bars anyone from later challenging an assessment in court unless they first filed a written objection with the Board of Review and presented evidence in good faith.
Your Right of Access
Wisconsin’s Public Records Law creates a strong presumption in favor of full public access. The statute says “any requester has a right to inspect any record,” and property tax data isn’t within the narrow exceptions. You don’t need to own property in Ozaukee County, live in Wisconsin, or explain your reason. The county must allow inspection and provide copies on request.