De Pere, WI Accessory Structures: ADU Rules (2026)

Backyard cottages are a form of accessory dwelling unit that Section 14-27 allows in every residential district, but only on a lot that already holds a detached house; a lot with a secondary suite, the interior version of an ADU addressed at Section 14-78(11), cannot also add a backyard cottage, and no more than one backyard cottage is permitted per lot. The combined number of residents in the cottage and the principal dwelling can't exceed what a single household is allowed under the city's occupancy rules, plus two additional residents.

At least one of the two dwellings on the lot, either the detached house or the cottage, must be occupied by an owner holding at least a 50 percent interest in the property, and that owner must live there as a permanent residence for at least six months of every calendar year. Before the city issues a building permit for a backyard cottage, the property owner must record a deed restriction committing to the owner-occupancy and rental limits and to notify future buyers of them; the restriction runs with the land, binds heirs and successors, must be in a form the development services director prescribes, and proof of recording must be filed before permits issue.

Backyard cottages cannot be used as short-term rentals, and a completed cottage cannot be sold separately from the principal house. Converting an existing accessory building into a cottage carries its own setback cross-reference: the rear and interior side setbacks match whatever applies to that accessory building type, except the rear setback must still be at least 25 feet where the rear yard adjoins a neighboring side yard. All backyard cottages must meet applicable Uniform Dwelling Code and building code standards.