Building permits in DuPage County, Illinois
Find the right authority before you build. DuPage County permitting follows Illinois law — here is exactly who issues the permit and where to start.
County + cities (mixed)
DuPage County Building & Zoning Department (unincorporated areas); municipalities issue their own permits
DuPage County Building & Zoning issues building permits only for unincorporated areas of DuPage County. Properties inside an incorporated city or village (e.g., Wheaton, Naperville, Glen Ellyn) are permitted by that municipality, not the county.
Permit cheat-sheet (Illinois rules)
| Project | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | Permit required | city | No flat statewide fee; Chicago calculates fees from construction type, occupancy, square footage, and scope via its online calculator. Other municipalities set their own fees. | — | Case by case | Illinois has no statewide building code; most municipalities use the IRC while Chicago enforces the 2019 Chicago Building Code. ADUs require a building permit plus local zoning approval — Chicago and other cities regulate ADUs through zoning. Verify with your municipality. |
| 🪵 Deck / Porch | Permit required | city | Chicago fees via online calculator; other municipalities set their own. | — | Generally allowed | Decks and porches require a permit (Chicago requires permits for decks/porches). Chicago offers an Express Permit for eligible deck work; most other IL towns follow IRC R105. |
| 🧱 Fence / Wall | Conditional | city | — | — | Generally allowed | Chicago requires a permit for fences (handled via the Express Permit Program). Other Illinois municipalities often exempt fences at or below 6 ft. Verify locally. |
| 🛖 Shed / Outbuilding | Conditional | city | — | — | Generally allowed | Larger sheds and any shed with utilities require a permit. Confirm the threshold with your local building department. Exempt: Under ~120 sq ft typically exempt under the IRC; varies by municipality. |
| 🪜 Basement Finish | Permit required | city | Municipal building permit fee; varies with scope. | — | Generally allowed | Finishing a basement into habitable space requires permits for egress, framing, electrical, plumbing, and mechanical work. Sleeping rooms need code-compliant egress. |
| 🚗 Garage / Carport | Permit required | city | Municipal building permit fee. | — | Generally allowed | A new garage requires a permit. Chicago’s Easy/Express Permit covers private (detached frame) garages; elsewhere a standard building permit applies. |
| ☀️ Rooftop Solar PV | Permit required | city | Electrical/structural permit fee set by municipality. | — | Generally allowed | Rooftop solar PV requires an electrical and structural permit. Chicago’s Express Permit covers small-scale residential solar PV; other municipalities issue a solar/electrical permit. |
| 🌡️ HVAC Replacement | Permit required | city | Mechanical permit fee set by municipality. | — | Generally allowed | Furnace, AC, or heat-pump replacement requires a mechanical (HVAC) permit and inspection. Chicago requires a city-licensed mechanical contractor. |
| 🍳 Kitchen Remodel | Permit required | city | Building permit fee; trade permits billed separately. | — | Generally allowed | A permit is required when relocating plumbing/electrical, moving walls, or changing fixtures. Cosmetic-only work may be exempt. |
| 🛁 Bathroom Remodel | Permit required | city | Building permit fee; trade permits billed separately. | — | Generally allowed | A permit is required when relocating plumbing/electrical, moving walls, or changing fixtures. Cosmetic-only updates may be exempt. |
| 🏗️ Room Addition | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | — | Generally allowed | Room additions change the footprint and require a full building permit and zoning approval. Chicago uses the 2019 Chicago Building Code for plan review. |
| 🪟 Window / Door Replacement | Conditional | city | — | — | Generally allowed | Swapping windows or exterior doors in the same opening is usually permitted via an expedited process; enlarging openings requires a full permit. |
| 🏘️ Roof Replacement | Permit required | city | Roof-covering permit fee set by municipality. | — | Generally allowed | Re-roofing is covered by Chicago’s Express Permit; elsewhere a roofing permit is required. Minor repairs may be exempt. |
| 🅿️ Driveway / Parking Pad | Conditional | city | — | — | Generally allowed | A permit may be required where the driveway connects to the street/right-of-way or triggers an excavation/erosion permit. Verify locally. |
| 🏊 Swimming Pool / Spa | Permit required | city | Building permit fee; barrier fencing required by code. | — | Generally allowed | Pools require a permit and barrier. Chicago processes pools via its Express/specialty permit programs; other municipalities issue a standard permit. |
| 🧱 Retaining Wall | Conditional | city | — | — | Generally allowed | Height and whether the wall supports a surcharge (driveway, structure, or slope above) determine the permit threshold. Verify with your municipality. |