Data report
713 solar permits were filed in Cook County (Suburbs) during 2025, pulled by 574 different contractors. These are the most active, ranked by the number of permits each pulled. Every figure comes from public building-permit records, not self-reported activity.
Year over year
Solar permits in Cook County (Suburbs) rose 266% versus 2024 — from 195 to 713 permits.
Solar leaderboard · 2025
Method
Every figure is drawn from public building-permit records filed in Cook County (Suburbs). A permit is counted once, by the contractor named on it. Installer names are grouped so minor spelling and entity-suffix variations (for example “Inc” vs “Inc.”) count as one company. This is recorded work, not survey data or self-reported claims, and it is reproducible from the public record.
Caveats
A permit reflects a job filed with the local building department. It is a strong proxy for installation activity but is not identical to completed work. Coverage is built from the records each jurisdiction publishes, so a contractor working without listing a name on the permit will not appear here.
See the full permit-verified track records behind these numbers: solar and other contractors in Cook County (Suburbs), or browse all of Illinois.