Accessory Structures in Fitchburg, WI: What Residents Actually Need to Know

If you live in Fitchburg or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Fitchburg has 2 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

Shed Rules

Fitchburg permits residential storage sheds up to 400 square feet in floor area and 15 feet in height, with a minimum 4-foot setback from any side or rear lot line and the principal-structure front-yard setback. A Deck and Shed Permit is required for any shed 64 square feet or larger; sheds smaller than 64 square feet are permit-exempt but must still meet setback and lot-coverage rules.

Key details: Permit Threshold: 64 sq ft. Max Floor Area: 400 sq ft. Max Height: 15 ft. Side/Rear Setback: 4 ft minimum. Lot Coverage Cap: 35 percent.

Building a shed without a required Deck and Shed Permit, exceeding 400 square feet, exceeding 15 feet in height, or placing the shed within 4 feet of a lot line violates Fitchburg Code Chapters 22 and 35. Building Inspection (608-270-4240) can issue stop-work and correction orders, require after-the-fact permitting, and refer continuing violations for citation and forfeiture. Lot coverage above 35 percent must be reduced before a permit is issued.

If you are coming from a city with tighter rules, you will find Fitchburg gives residents more flexibility on shed rules.

ADU Rules

Fitchburg permits 'dependency living arrangements' (ADUs) as a conditional use in R-L Low Density and other residential districts under §22-57. The accessory unit may not exceed 750 sq ft, one of the two units must be owner-occupied, and at least one interior doorway must connect the units. Separate front entrances are prohibited unless required for handicapped accessibility. Authority: Wis. Stat. §62.23.

Key details: Code Section: Fitchburg §22-57 (R-L). Size Limit: 750 sq ft maximum. Owner-Occupancy: Required on one unit. Approval: Conditional use permit. State Law: Wis. Stat. §62.23.

Operating an unpermitted second dwelling unit is a zoning violation; remedies include stop-work orders and forfeitures under Ch. 22 enforcement provisions.

The Bottom Line

Fitchburg'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 Fitchburg is broadly strict or permissive.

This guide is based on Fitchburg's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.