🏙️ Illinois

Home Battery Storage Permit Requirements in Illinois (2025)

Last updated: June 2025

Illinois Bottom Line: A permit is required in all Illinois cities. Chicago has its own comprehensive building permit process; suburbs vary by municipality. Typical fees: $175–$450. ComEd handles Chicago-area utility interconnection (3–6 weeks). Illinois adopted the 2020 NEC in 2023.

How Illinois Battery Permits Work

Illinois jurisdictions operate independently. Chicago operates under the Chicago Building Code with its own permit process through the Department of Buildings (DOB). Cook County suburbs each have their own building departments. Downstate Illinois cities follow municipal codes based on the IBC/NEC.

The Permit Process

Chicago requires permits through the Chicago Department of Buildings (DOB). Residential electrical permits in Chicago can be filed online but often take 3–5 weeks for battery storage systems. Suburban Cook County cities are typically faster (7–14 days). ComEd's interconnection application for residential storage takes 3–6 weeks.

Documents Required

Required: permit application, single-line diagram, UL 9540 spec sheets, Illinois licensed electrical contractor (IDFPR license), site plan. Chicago may require a structural engineer's letter for wall-mounted batteries above certain weights.

  1. Permit application — from your local building department
  2. Single-line electrical diagram
  3. Equipment spec sheets with UL 9540 listing
  4. Licensed contractor license number
  5. Site plan

FAQ — Illinois

In virtually all incorporated areas of Illinois, yes. Always verify with your specific local building department before proceeding without a permit.
Typical review times range from 5 to 21 business days depending on your city. Your installer can give a current estimate for your specific jurisdiction.
Most reputable installers handle permit filing as part of the installation package. Confirm this is included before signing and ask for the permit number once issued.
Informational only — not legal or electrical advice. Verify with your local building department.
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