Green Bay's Accessory Structures: The Rules That Matter

Every city handles accessory structures a little differently. In Green Bay, Wisconsin, there are 2 distinct rules that residents and property owners should be aware of. Some are stricter than what neighboring cities enforce, and others are more relaxed. Here is what you need to know.

Shed Rules

Sheds in Green Bay are detached residential accessory structures regulated under Section 44-590 and Table 44-4 of the Green Bay Municipal Code. Sheds under 50 square feet are exempt from a building permit but must still meet zoning. Detached sheds in one- and two-family districts must sit behind the principal building (or in the side yard not abutting a street) with a 4-foot side and 4-foot rear setback (2-1/2 feet on narrow lots), a 55-foot front setback, and at least 3 feet between accessory structures.

Key details: Code Section: Sec. 44-590. Permit-Free Threshold: Under 50 sq ft. Side/Rear Setback: 4 feet. Max Height: 16 feet. Metal Shed Cap: 120 sq ft.

A shed installed without a required permit, in front of the principal structure, in a side yard abutting a street, or inside the 4-foot setback violates Section 44-590 and is enforceable by the Green Bay Inspections Division. Typical responses include a stop-work order, an order to relocate or remove the structure, and after-the-fact permitting fees. Continued non-compliance is a Chapter 44 zoning forfeiture and may be referred to the City Attorney for abatement.

ADU Rules

The City of Green Bay regulates accessory dwelling units under Chapter 44 of the Code of Ordinances (Zoning), adopted under the city's zoning authority in Wis. Stat. Sec. 62.23. Following a December 2025 rewrite of the zoning code (the first major update since approximately 2006), accessory dwelling units are allowed in all residential districts with an approved Conditional Use Permit (CUP). An ADU on the same parcel as a single-family, two-family duplex, or two-family semi-detached dwelling provides complete independent living facilities for one family consistent with the Wisconsin Uniform Dwelling Code. With an approved CUP, the ADU does not count as an additional accessory structure for the lot.

Key details: Chapter 44 (Zoning): Chapter 44 (Zoning) of the Green Bay Code of Ordinances governs ADUs. ADUs are allowed: ADUs are allowed in all residential districts only with a Conditional Use. December 2025 zoning: December 2025 zoning code update was first major rewrite since about 2006. ADU defined as: ADU defined as second dwelling on parcel with single-family or two-family use. ADU with approved: ADU with approved CUP does not count as an additional accessory structure.

Constructing or occupying an accessory dwelling unit without an approved Conditional Use Permit and required building permits is a violation of Chapter 44 of the Green Bay Code of Ordinances. Enforcement actions can include stop-work orders, citation and forfeiture under the city's general penalty provisions, and orders to remove or modify non-conforming structures. Operating an ADU outside the conditions imposed in the CUP (for example, an unauthorized short-term rental use, exceeding occupancy, or violating site-specific conditions) can lead to revocation of the CUP and additional penalties.

The Bottom Line

Green Bay's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Green Bay is broadly strict or permissive.

Keep in mind that Green Bay can amend these rules at any council meeting. For the most current version of any rule mentioned here, check the specific ordinance page, where we track updates as they happen.