WISCONSIN ACCESSORY DWELLING UNIT (ADU) ZONING CODE UPDATES. In recent years, Vandewalle & Associates has helped numerous communities tackle the housing shortage and affordability from multiple fronts. One of the most powerful tactics involves zoning code rewrites.
By incorporating permissive ADU provisions as standard practice, these changes can allow more flexible home sizes, enable multigenerational housing, and accommodate income-producing ADUs on existing residential lots—all of which help increase missing-middle housing density across Wisconsin.
Specific communities with ADU updates penned by V&A include:
- Mount Horeb: Its recent overhaul introduced detached and attached ADUs for the very first time, capped at 800 square feet.
- Middleton: Its award-winning comprehensive rewrite legalized ADUs up to 900 square feet under strict owner-occupancy rules.
- New London: The 2024–2025 overhaul written by Vandewalle expressly legalized “by-right” ADUs and in-family suites across all single- and two-family zoning districts.
- Milton: Updated its ordinances to legally define and permit ADUs within its residential zones.
- Monroe: The community allowed ADUs as part of its code rewrite.
- Several other Wisconsin communities are currently examining and overhauling their zoning codes to make them future-ready with guidance from Vandewalle & Associates’ planning and development expertise. These include Watertown, Columbus, Shorewood Hills, and Oregon.
COTTAGE COURT ORDINANCES. Another interesting and highly publicized zoning update expands opportunities for smaller homes and shared resources. Sometimes called “Cottage Court” or “Group Zoning” Ordinances, this zoning type enables up to eight detached tiny/small homes around a shared courtyard on a single lot. Vandewalle & Associates has added this provision to the Dane County Residential Zoning Code Best Practices Guide, as well as the ADU and other more flexible provisions.