Illinois allows tenants to use repair-and-deduct in single-family rentals (except condominiums) and multi-family housing (except for owner-occupied buildings of six units or less; other exemptions apply). Rent withholding is available only when a property is in receivership for utility interruptions. For details, see the Illinois Residential Tenants' Right to Repair Act.
For an overview of Illinois landlord-tenant law, including your rights to habitability, see "Your Rights as a Landlord or Tenant in Illinois," published by the the Self Help Legal Center at Southern Illinois University School of Law.
Also, check your local housing ordinances for any city or county rules that cover tenant rights when it comes to repairs. Contact your local building or housing authority. To find yours, call your mayor or city manager’s office or check your city or county website.