In Illinois, "I'm licensed in the state" can mean one of three completely different things depending on who issued the credential and where the work sits. The Illinois Department of Financial and Professional Regulation (IDFPR) licenses roofing contractors and plumbers statewide. The Chicago Department of Buildings (CDOB) runs an entirely separate registry for general contractors, electrical contractors, plumbing contractors, and masonry contractors operating inside the city. Everywhere else in Illinois — the suburbs, the collar counties, downstate — there is no state GC license at all, and most trades run on municipal permits issued building-by-building.
The two state-level portals do not reciprocate. A Chicago electrical contractor is not on IDFPR. A statewide IDFPR roofer is not on CDOB. A contractor working both sides of the city line needs both credentials, and a buyer checking only one portal has verified roughly half of what they think they verified.
This guide walks both portals step-by-step, decodes the Chicago Class A/B/C classification system that caps what a GC can legally bid, and lists the red flags specific to the Illinois split.
Why Illinois verification is structurally different
Most large states either license general contractors statewide (California, Florida, Virginia, Arizona) or license almost nothing and push every trade to the municipal level (Texas, Pennsylvania). Illinois sits between the two and lands at the worst of both: the state issues a real, statutorily-grounded license for a narrow set of trades, then quietly hands the rest of the construction economy to the City of Chicago and to the home-rule suburbs.
The state-level credentials are anchored in two statutes. The Illinois Roofing Industry Licensing Act (225 ILCS 335) requires anyone holding out as a roofing contractor in Illinois to carry a current IDFPR roofing license, with separate Limited (residential and small commercial) and Unlimited classifications. The Illinois Plumbing License Law (225 ILCS 320) governs plumbing licensure statewide and is administered through the Illinois Department of Public Health for individual plumber licenses, with the contractor side touching IDFPR for business registrations. Both acts carry administrative penalties enforced through the relevant state agency.
Inside Chicago, the controlling law is the Chicago Municipal Code, primarily Title 4 (Businesses, Occupations, and Consumer Protection) for general contractor and trade-contractor licensing. CDOB enforces against the city's own registry, and operating regulated trade work inside Chicago without the city credential is a municipal offense with citation penalties and permit denials — not a state administrative matter.
The practical consequence: a roofer working a residential job in Naperville needs the IDFPR roofing license and the Naperville permit. A general contractor running a kitchen remodel in Lincoln Park needs the CDOB General Contractor license. A plumbing contractor working a multi-unit in Evanston needs the IDFPR/IDPH credential and the Evanston permit, and if the same firm also takes work in the city it needs a separate Chicago Plumbing Contractor license on top. Three different jobs, three different verification paths, one phrase that covers all of them in marketing copy.
The IDFPR verification process (for roofers and plumbers statewide)
Step 1 — Open the IDFPR License Lookup. Go to the IDFPR License Lookup portal. IDFPR licenses dozens of professions through the same database — roofing contractors, plumbers, pharmacists, accountants, cosmetologists — so the first step is to filter the Profession dropdown to Roofing Contractor or Plumber (or the relevant plumbing-contractor category, depending on whether you're verifying an individual or a business).
Step 2 — Search by name, not by license number. As with any state portal, the contractor will hand you a license number. Don't lead with it. Search the contractor's name or business name first, then confirm the license number that comes back matches what you were handed. IDFPR license numbers are issued sequentially across many professions and recycled less aggressively than some state systems, but the underlying anti-fraud principle still applies: it's harder to fake a name than a number on a business card.
Step 3 — Read every field on the record. A complete IDFPR record shows you:
- License Type — Roofing Contractor (Limited or Unlimited) for roofers, with the classification determining authorized scope; the plumbing side surfaces both individual Plumber licenses and Plumbing Contractor business registrations. The type is scope-locked. A Limited Roofing Contractor cannot legally take on the commercial-scale work an Unlimited classification authorizes.
- License Status — Active, Lapsed, Inactive, Suspended, or Revoked. Active is the only status that permits new work. Lapsed in Illinois means the renewal cycle was missed and the licensee is not currently authorized to operate until the renewal is cured — the record still resolves, but the credential is not work-eligible. Suspended typically traces to a disciplinary matter, an unresolved continuing-education lapse, or an outstanding civil penalty. Revoked is terminal.
- Expiration Date — confirm the date is in the future, and confirm the contractor isn't quoting work that will extend past expiration without a renewal already in hand.
- Disciplinary Actions — IDFPR exposes formal orders against a license on a separate tab. Most consumers never click it. Three open or recent disciplinary matters in the same scope as your job is a different risk profile than zero.
If the license type doesn't authorize the work, the status isn't Active, or the expiration is past, the verification has failed regardless of how clean the other fields look.
The Chicago Department of Buildings verification process (for GC, EC, PC, and masonry inside city limits)
Step 1 — Open the CDOB contractor lookup. The Chicago Department of Buildings contractor and trade-license search is the city's own portal. The same data is also available as a continuously-updated table on the Chicago Data Portal — search "Building Contractors" — which is the dataset most pro sourcers actually pull from for bulk lookups. For one-off verification, the building-records portal is the simpler path.
Step 2 — Filter by license type, then search. CDOB distinguishes several trade categories on the same portal: General Contractor, Electrical Contractor, Plumbing Contractor, Mason Contractor, and a handful of specialty registrations. Filter to the relevant type first — a CDOB General Contractor record and a CDOB Electrical Contractor record live in the same search but mean different things.
Step 3 — Read the class and status fields together. A complete CDOB record shows the trade type, the Class designation for General Contractors (see the next section), the license status (Active, Expired, Suspended, Revoked), the expiration date, and the qualifying-individual fields where applicable. CDOB also exposes the business address and the principal officers on the license record, which is one of the few places the qualifier-versus-business relationship is publicly traceable.
If the contract is for work inside Chicago and the contractor's record isn't on the CDOB portal, the IDFPR check by itself does not authorize the work. Both portals exist for a reason.
The Chicago Class A/B/C trap (the IL gotcha most buyers miss)
CDOB classifies General Contractors into three monetary-cap tiers, plus a Specialty Limited license for narrowly-scoped trades. The class determines the maximum total project value the GC can legally bid or perform inside Chicago, and the cap is a hard ceiling, not a soft suggestion.
- Class A — General Contractor (Unlimited). No project-value cap. Authorized for any project size CDOB otherwise permits.
- Class B — General Contractor (Limited). Project-value cap in the low millions. The exact threshold is set by ordinance and adjusted periodically — confirm the current dollar figure against the CDOB contractor licensing page before signing a contract anywhere near the limit.
- Class C — General Contractor (Restricted). Project-value cap in the mid-six-figure range — again, confirm the current dollar figure before relying on it. Often the right tier for small remodels and single-family work.
- Specialty Limited. Narrow-scope licenses for specific trade work that doesn't require the full GC credential.
The trap is straightforward and routine. A Class C contractor bids and wins a project whose total value puts it over the Class C cap. The CDOB permit application either gets denied at intake (best case — annoying but recoverable) or slips through, the work proceeds, and a complaint or audit later voids the permit retroactively. At that point the homeowner or owner is stuck with completed-but-unpermitted work that has to be inspected, re-permitted, or in the worst cases torn out and redone under a properly-classed contractor.
Verifying the class against the project's total value is the Illinois-specific step that buyers used to working in unlimited-class states (California, Florida) routinely skip. Pull the class on the CDOB record. Compare it to the contract value. If they don't line up, either the contractor needs to subcontract the overage to a properly-classed firm or you need a different prime.
Red flags specific to Illinois
"Illinois-licensed general contractor" without naming the jurisdiction. Outside Chicago, no Illinois state general-contractor license exists. A GC making this claim is either confused about the difference between state and municipal licensure or is hoping the buyer is. The honest answer is either a Chicago Department of Buildings GC license (with a Class), a Chicago suburb's contractor registration (Naperville, Aurora, Schaumburg, Oak Park, Evanston, and many others run their own registration programs), or no GC credential at all because the relevant jurisdiction doesn't require one. Ask which credential, specifically, they're referring to.
A CDOB Master Plumber license held without the IDFPR/IDPH companion. Inside Chicago, plumbing work technically implicates both the Chicago Plumbing Contractor license and the underlying Illinois Plumbing License Law credentialing for the individual plumber. A firm running a CDOB Master Plumber relationship whose IDFPR-side individual plumbing license has lapsed is operating with a permission gap most buyers never check. Pull both portals for plumbing work in Chicago.
A Class C contractor bidding a project above the Class C cap. Read the class on the CDOB record. Read the project value on the contract. If the contract value exceeds the class cap, the verification has failed, regardless of how clean the other fields look. This is the single most common Illinois-specific verification failure.
A qualifying specialty contractor no longer with the firm. As with most jurisdictions, the CDOB Electrical Contractor and Plumbing Contractor licenses are tied to a qualifying individual whose credentials anchor the firm's authority. If that individual leaves — retires, changes employer, dies — the firm's authority for that trade evaporates until a new qualifying individual is recorded with CDOB. The license number on the truck does not change; the legal authority behind it does. Confirm the qualifying individual on the current CDOB record is actually the person still doing or supervising the work.
An IDFPR Limited Roofing Contractor quoting commercial work. The Limited classification under 225 ILCS 335 is scope-locked to residential and small commercial. A Limited holder bidding a large commercial reroof is operating outside class, and the resulting permit complications are the buyer's problem first.
What neither portal tells you
Worth being honest about the limits of both public records.
Insurance status is not surfaced live. Both IDFPR and CDOB collect proof of general liability insurance (and, for CDOB, the city-specific bonding requirements) at licensing and renewal milestones. Neither portal displays real-time coverage status. A contractor can drop coverage mid-cycle and the portal won't reflect it. Request a current Certificate of Insurance naming your property or project as the certificate holder, and confirm with the insurer that the policy is in force.
Workers' compensation runs through a separate agency. Illinois workers' comp coverage is verified through the Illinois Workers' Compensation Commission (IWCC), not through IDFPR or CDOB. For any contractor putting employees on your property, run a separate IWCC search or request a current Certificate of Insurance showing workers' comp coverage and verify directly with the insurer.
Mechanic's-lien history lives at the county recorder. Illinois mechanic's liens are recorded in the county where the property sits — Cook County for Chicago, DuPage for Naperville and Wheaton, Lake for the north shore, Will for the south suburbs, Kane for Aurora and Elgin, McHenry for Crystal Lake, Winnebago for Rockford, Sangamon for Springfield. A contractor with a clean IDFPR and CDOB record can still have a documented pattern of recording liens against past clients' properties, and the licensing portals will not surface it. For high-stakes contracts, a county-records search is part of the diligence.
EPA Section 608 certification is federal. Anyone handling refrigerants on an HVAC or refrigeration job needs federal EPA Section 608 certification under the Clean Air Act. Neither IDFPR nor CDOB verifies Section 608 — confirm it separately through the EPA-approved certifying organization. (Note that HVAC contractors are not state-licensed in Illinois at all; verification for HVAC work runs through the municipal permit and the federal refrigerant credential, not through a state portal.)
Suburban registrations are entirely separate. Naperville, Aurora, Schaumburg, Evanston, Oak Park, Arlington Heights, and dozens of other Chicago-area municipalities run their own contractor and trade-registration programs on top of (or instead of) the state credentials. For work outside Chicago city limits, the municipal registration in the project's jurisdiction is the operative credential, and there is no statewide rollup that surfaces them.
Sourcing licensed Illinois contractors at scale
ContractorRoster maintains a continuously-updated mirror of both the IDFPR and CDOB registries for the trades we cover — 14,951 active Illinois records combining IDFPR roofers statewide with Chicago Department of Buildings GCs, electrical contractors, plumbing contractors, and mason contractors — with phone, email, website, and Google ratings layered in. For one-off verification of a name you've already been handed, the free IDFPR License Lookup and the Chicago Department of Buildings contractor search above are the source of truth — the right tools for the last-mile check before signing.
For sourcing multiple licensed contractors at scale — a property manager building a vendor roster across the Chicago metro, a supplier launching into Cook and the collar counties, a developer running an RFP on a multi-property rehab — our $39 CSVs at /illinois pull the same IDFPR and CDOB data pre-enriched with the contact info neither portal publishes. Illinois accounts for roughly 2.4% of the 618,395 active licenses we mirror across 15 states.
One scope note worth restating: HVAC, solar, fire-protection, landscape, and most sub-trades have no Illinois state-level license and no centralized Chicago equivalent, so they are not in the Illinois dataset — there is no state or city registry to mirror for those trades. Outside Chicago, GC and trade verification has to happen city-by-city through municipal registration programs, and verification has to happen through insurance, references, and the contract.
Either way, the verification rules above don't change. Even from a pre-enriched roster, the last check before you sign is to pull the license on the relevant portal — IDFPR for roofers, CDOB for Chicago GCs and trades — and confirm the type, status, class, and expiration yourself.
Related reading
Illinois is one of the clearest cases of the two failure patterns the cross-state guides catalog. For the verification-budget side of operating across multiple states with portals of varying transparency, see Ranking the 13 State Contractor License Portals — Illinois sits at 2/5 precisely because of the IDFPR/CDOB split. For the abstracted checklist of how license verification fails across any jurisdiction, see Eight Ways Contractor License Verification Goes Wrong — Trap 3 (state license versus local registration), Trap 7 (cross-jurisdiction mismatch), and Trap 2 (qualifier-versus-business confusion) all fire in Illinois on a routine basis.
Next step
Browse licensed Illinois roofers, general contractors, electricians, plumbers, or masonry contractors — every record sourced from the IDFPR and CDOB registries above, with the contact info neither portal publishes. For the trades Illinois doesn't license at the state level and that lack a centralized Chicago registry (HVAC, solar, landscape, fire-protection, painting, drywall, tile, flooring, carpentry, concrete, excavating), verification runs through the relevant municipal permit office and the project's insurer — there is no statewide list to pull from.
Or run a one-off check at the official IDFPR License Lookup for roofing and plumbing, and the Chicago Department of Buildings contractor search for GC, electrical, plumbing, and masonry work inside city limits.