In Appleton, building permits come from the City of Appleton Inspection Division, and whether your wall needs one is that office's decision. We check with them before work starts, and when a permit is needed we pull it ourselves and keep the paperwork in order. If you have a question about your own project, the Inspection Division is the place to ask.
Wisconsin's code sets how deep footings go. They sit below the frost line or at least 48 inches below the ground beside them, whichever is deeper, and that covers footings for landings and stoops too. They also go on undisturbed or compacted soil free of organic material, unless the footing is reinforced to bridge poor ground, so a block foundation here starts with a deep, clean trench.
For a home under construction, the state calls for a complete drain tile or pipe system around the foundation where groundwater sits above the bottom of the footing, and the rule says a city may not require a complete system for an alteration to an existing home. We see both kinds of work around Appleton and in nearby cities such as Grand Chute and Neenah, from additions on older houses to yard walls on newer lots.