How Springfield Handles Accessory Structures: A Practical Guide
Springfield maintains 122 local ordinances across all categories, and 3 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Springfield falls on the strict-to-permissive spectrum compared to other cities.
Shed & Carport Rules
Springfield Zoning Ordinance Section 155.068 allows detached sheds and accessory buildings in the rear yard, requiring at least a 3-foot setback from any property line, a 6-foot separation from the principal building, and an 18-foot maximum height in residential districts. Section 155.062 lists accessory sheds among permitted rear-yard obstructions.
Key details: Code Section: Zoning Ord. 155.068; obstructions 155.062. Rear-yard property-line setback: 3 ft minimum. Separation from principal building: 6 ft minimum. Max height (residential): 18 ft. Allowed location: Rear yard; not in front yard or required side yard.
A shed or accessory building placed closer than three feet to a property line, within six feet of the principal building, in a front yard, or exceeding 18 feet in height violates Section 155.068 and is subject to the zoning penalty cross-referenced at Section 155.999, which can require relocation or removal of the structure.
ADU Rules
Springfield's zoning code expressly prohibits using any detached garage, accessory building, or structure as a dwelling unit, so a freestanding accessory dwelling unit (ADU) is not permitted under Zoning Ordinance Section 155.068(b)(2). Illinois has no statewide ADU law in force (HB 1813 remains pending), so the local ban governs.
Key details: Code Section: Zoning Ord. 155.068(b)(2). ADU as dwelling: Prohibited - no detached accessory structure may be a dwelling unit. Max accessory height (residential): 18 ft. State preemption: None in force; IL HB 1813 pending, not enacted (2026). Path to a second unit: Variance/text amendment via Planning & Zoning Commission.
Using a detached garage or accessory building as a dwelling violates Section 155.068 of the Zoning Ordinance and is subject to the zoning penalty cross-referenced at Section 155.999, plus code-enforcement action requiring the unauthorized living space to be vacated, removed, or brought into a permitted use.
Compared to other cities, Springfield takes a harder line on adu rules. The enforcement and penalty structure reflects that.
Garage Conversions
Springfield's zoning code bars converting a detached garage or accessory building into a dwelling unit or a business: Section 155.068(b)(2) states no portion of such a structure may be used as a dwelling unit or for any business or office use. Converting an attached garage into living space is treated as altering the principal building and requires a permit.
Key details: Code Section: Zoning Ord. 155.068(a)-(b)(2). Detached garage to dwelling: Prohibited. Detached garage to office/business: Prohibited. Attached garage: Treated as part of principal building; permit required. Building permit: Required for garage construction/alteration.
Occupying a converted detached garage as a dwelling, office, or business violates Section 155.068(b)(2) and is subject to the zoning penalty cross-referenced at Section 155.999. Converting garage space without a building permit also violates the city building code and can trigger stop-work orders and after-the-fact permit fees.
This is one of the stricter rules in Springfield's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.
The Bottom Line
Springfield is tougher than many cities when it comes to accessory structures. Out of the 3 rules covered here, 2 are rated strict. If you are a homeowner, renter, or business owner in Springfield, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.
Keep in mind that Springfield 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.