Blog · October 14, 2026 · Wisconsin
Using the Grafton Flood Zone Map
Flood zones are set by FEMA, and checking one near Thiensville takes a few minutes.
Main page: Ozaukee County, WI GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Before you buy or build near Thiensville, check the Grafton flood zone map: FEMA's zone label affects insurance, permits and resale. What this Grafton guide covers: locating a parcel on FEMA's map, decoding A, AE and X, and matching it with the county parcel viewer.
Checking the Grafton flood zone map step by step
Flood zones come from FEMA's Flood Map Service Center: type an address near Cedarburg, and pick the FIRMette or map view. Vacant ground around Mequon can still be found: zoom in from Interstate 43 and click the spot.
Getting to the right map
Your first stop is the Ozaukee County parcel viewer; it maps every tax parcel in the county, Port Washington included. When a rural tract has no street number, pan along Interstate 43 until the lines appear, then click inside the one you want. Out toward Port Washington, a pop-up or side panel normally shows the owner of record, assessed acreage, a parcel ID and sometimes recent sales.
Sections, lots and bearings
Wisconsin uses the Public Land Survey System, which means a tract near Cedarburg is described by section, township and range. Each section is nominally a mile square, about 640 acres, with 36 sections to a township, though sections near Port Washington can be irregular. Keep the legal description for land near Newburg for any title or survey request.
Field tips
Most viewers work in a phone browser, which helps when you're standing on land near Thiensville, so load it before you lose signal. A saved image of the lot near Port Washington and its lines helps when you meet an owner or agent.
Grafton, WI: the basics
Grafton lies within Ozaukee County, Wisconsin, so its parcels are on the county's map. For a home near Cedarburg, city or town hall handles matters such as zoning, permits and utilities within town limits, while the county keeps the tax map. Land beyond the city limits near Saukville generally follows county rules, not municipal ones.
Neighboring parcel maps
Ozaukee County borders Muskegon County, MI, Oceana County, MI, Milwaukee County, Sheboygan County, and Washington County, and each of those keeps its own parcel map. Ground near Cedarburg that runs to the line may be split in two county records, so open the adjacent map before you assume the acreage. On ground around Port Washington, the Platbookmapper state page links each neighboring county map across Wisconsin.
What to request from a seller
Request for any Elevation Certificate on the property near Mequon; an insurance quote early keeps the budget honest.
What the zone letters mean
Zone AE carries a published BFE, which plain A zones lack; builders around Cedarburg design to it. With a lot near Newburg, a shaded X area is moderate risk, roughly the 100- to 500-year range; unshaded X means minimal mapped risk.
Places you'll see on the map
Port Washington is the county seat, home to the main records offices. Other places on the map include Cedarburg, Saukville, and Thiensville, each with its own cluster of lots. About 93,460 people live in Ozaukee County (Census Bureau estimate, 2023) across about 233 square miles. Ozaukee County dates to 1853, and some chains of title near Thiensville are long. Places such as Lake Michigan and Lion's Den Gorge Nature Preserve help you orient on the aerial around Newburg.
Limits of the parcel data
Listed acreage is an estimate; only a licensed surveyor can set the real corners on land around Thiensville. Records update in batches, so a fresh transfer around Saukville may not show yet.
The paper trail behind a parcel
The map is an index, not the title: deeds, plats and easements covering ground around Cedarburg sit with the Register of Deeds. Inherited tracts near Thiensville may go back through many deeds, and a title company earns its fee if money is changing hands.
Parcel lines plus flood zones
When the zone clips a corner of a lot near Saukville, the location of the house or building pad decides a lot.
Beyond the mapped zones
Small streams around Mequon may not have detailed mapping, so look for water marks and debris lines. Marshy spots near Cedarburg can limit building too; check the National Wetlands Inventory mapper for a first look.
Insurance, lenders and building
For a tract near Mequon, an Elevation Certificate from a surveyor helps: it compares the building to the BFE. New construction in a floodplain near Cedarburg can trigger elevation rules; ask the local floodplain administrator before you plan.
Questions about the Grafton flood zone map
How often are flood maps updated near Newburg?
Usually, a new study can move a zone line near Saukville, so look at the panel date.
What is a base flood elevation for land near Saukville?
Generally, a BFE near Cedarburg tells builders how high the lowest floor should be; surveyors near Thiensville use it often.
How do I check the flood zone for an address in Grafton?
Search the address near Saukville on FEMA's Flood Map Service Center; no account is needed.
Is flood insurance mandatory near Newburg?
Lenders generally require it for buildings near Cedarburg in a Special Flood Hazard Area when the loan is federally regulated or insured; outside those zones it's your call.
How do I save a parcel from the viewer near Thiensville?
Most viewers have a print or export tool, and it's worth keeping the parcel ID visible for land near Cedarburg.
Open the official Ozaukee County, WI parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.