Do I need a permit for shed or accessory structure in Highland Park?

Most likely yes. Shed or accessory structure usually requires a permit in Illinois. Confirm the specifics with Highland Park.

Illinois has no single statewide shed threshold, so the 200 square foot figure quoted from the model International Residential Code does not govern here. Requirements are set by each municipality, and the ones we have checked are stricter than that figure: Wheaton does not require a building permit for a shed of 120 square feet or less, and Joliet requires a shed permit with a Residential Accessory Structures Review Form and a plat of survey showing the shed location. Assume the local number rather than a national one, and ask your building department for the threshold that applies at your address before you buy the shed. Zoning setbacks, easements and lot coverage still apply where no building permit is needed, and running electrical or plumbing to the shed triggers its own permit. Highland Park publishes a specific Shed permit requirements sheet and separate sheets for detached garages and other detached accessory structures, so a permit is expected for a backyard shed. Confirm the exact size threshold and whether your shed qualifies with the Highland Park Building Division before you build. Accessory structures must meet Chapter 150 zoning setback and lot-coverage rules even when they are small, and a plat of survey is used to verify placement. Do not assume a shed is exempt because it is not on a foundation. If your lot includes a ravine, bluff, or regulated drainage area, additional grading, stormwater, or Lake County Watershed Development review may apply to where the structure can go.