Planning
Waukesha County Shoreland Rules for Patios and Walls
If your parcel is near water, the county has views on what you may build and where. Patios and retaining walls are treated differently from each other - and Delafield differently again.
Most of this county is nowhere near navigable water and none of this applies. But Pewaukee, Delafield, Hartland and Muskego have real lake frontage, and plenty of parcels sit inside the shoreland band without their owners thinking of themselves as lakefront, the streets back from Pewaukee Lake among them. It is worth five minutes to find out which you are.
The baseline
Under the Waukesha County Shoreland and Floodland Protection Ordinance, structures set back at least 75 feet from the ordinary high water mark - or from the floodplain, or from the conservancy district boundary, whichever of those is greater.
That last clause catches people. On a parcel with floodplain or conservancy mapping the governing distance can be considerably more than 75 feet, so 75 is a floor rather than the answer.
Patios and walls are not treated the same
This is the part worth knowing, and it runs opposite to what people assume.
| Patios and decks | Retaining walls | |
|---|---|---|
| Setback averaging available? | Yes, as structures adjacent to a principal building | No - expressly excluded |
| Can be used as an averaging reference? | - | No, not even for another wall |
| Route to build closer | Averaging, or special permit | Only erosion abatement |
Setback averaging, and its floor
Where neighbouring principal buildings already sit closer than 75 feet, a new principal building and structures immediately adjacent to it - decks and patios among them - may take an averaged setback based on adjacent properties within 200 feet. One neighbouring non-conforming building of similar use gives you the average of its setback and the required minimum; two, one either side, gives you the average of the two.
The floor is 30 feet, and nothing goes closer regardless of what the neighbours managed.
Swimming pools and sports courts are excluded alongside retaining walls.
The special permit route
Separately, the zoning administrator may permit a structure closer than 75 feet where the nearest part sits at least 35 feet back from the water and the total floor area of everything in the shore setback area stays within 200 square feet. That is a real option for something modest, and a hard ceiling that counts what is already there.
Nothing is ever exempt from the conservancy district setback.
Retaining walls: erosion only
A wall inside the setback may be permitted where it is necessary to abate a known and identified soil erosion and sedimentation problem. That is a remedial provision. It is not a route to a terraced garden, and averaging cannot be used to get there either.
Delafield doubles it
Properties inside the Delafield Shoreland Overlay District face a minimum 150-foot setback from the ordinary high water mark for all structures, apart from boathouses and anything otherwise excepted. If you are in Delafield and near water, that is the number that governs, not 75.
What to do with this
Find out whether your parcel is in the shoreland band and whether floodplain or conservancy mapping applies, before a designer draws anything. It is a phone call to the county, and it is considerably cheaper than a layout that cannot be built. Municipal permits sit alongside all of this - see which office governs your project.