How to check a contractor's license in Missouri

Which license does the contractor need in Missouri?

The state licenses one construction trade. The statewide electrical contractor license "is optional, not mandatory" (OSEC FAQ). Holders must carry "liability insurance in the amount of $500,000" (OSEC FAQ; RSMo 324.920.1(2)), and cities and counties "shall recognize a statewide license in lieu of a local license" (RSMo 324.925.1; both from SB 240, 2017). So an electrician with a statewide license and no City license can be working legally in St. Louis.

Everything else is set by where the house is:

One catch on HVAC: the City's Mechanical Code "generally applies to regulated work in commercial structures", and the board's page says some residential buildings and lower-cost projects may be exempt. A furnace swap in a house may not need a City-licensed mechanical contractor; ask the Building Division, (314) 622-3313, before you treat a missing mechanical license as a problem.

City or County: which one are you in?

The City of St. Louis is an independent city. It is not part of St. Louis County, and a "St. Louis, MO" mailing address can be in either. If your property tax bill comes from the City Collector of Revenue, check with the City. If it comes from St. Louis County, check the County for trade licenses and your own town (or the County, if you are unincorporated) for the contractor's business license. Ballwin's page is typical: "Each contractor must have an active St. Louis County License in their respective field of expertise" on top of the city license.

The County's Department of Transportation and Public Works publishes an Electrical Contractor License page. Its site blocked our reader on 20 October 2026, so we quote no County fees or rules here; check that page or call the County directly.

How to look a contractor up in the City of St. Louis, step by step

1. Ask for two numbers: the Graduated Business License and, for electrical, plumbing or mechanical work, the City trade license (or the statewide electrical license).
2. Search the business on the License Collector's Business License Search by name (any part of the legal name) or City address. It shows only Graduated Business Licenses for the current fiscal year, which runs 1 June to 31 May, so a firm licensed last year but not renewed will not appear. If the name is missing, call the License Collector, (314) 622-4528 or lco@stlouis-mo.gov; firms are listed under their legal name, not a trade name.
3. Call the Building Division, (314) 622-3313 or dps-building-division@stlouis-mo.gov, to confirm the trade license. The board pages publish no list of license holders.
4. For a statewide electrical license, use the Licensee Search on the Division of Professional Registration site. We could not load it on 20 October 2026; if it fails for you, ask the Office of Statewide Electrical Contractors, osec@pr.mo.gov or (573) 522-3280.
5. Ask for the workers' compensation certificate. The City cannot issue the business license without one or a signed exemption affidavit (RSMo 287.061, cited on the license page).
6. In the May 2025 tornado zone, look the firm up on the City's STL Recovers contractor registry. Only "Verified Contractor" means the City checked the business license, insurance and trade certificates; "Submitted, not Verified" means nobody has. The verified placard carries the City Seal and a QR code.
7. Before work starts, confirm who is pulling the permit. City electrical permits go only "to licensed electrical contractors certified by the City of St. Louis", with a $25 application fee (Building Division).

What the license does not tell you

A City business license says the firm registered, paid and showed workers' comp. It says nothing about whether its permits were finished. The City's building permits do, and we read them:

Two things follow. Most firms have almost no record: 72.9% of remodel firms pulled one permit in three years, so for them the license calls above are most of what you can check. And among the 22 remodel firms with 10 or more permits, the finished share runs from 29.3% at the 10th percentile to 91.0% at the 90th. All of them can hold the same business license.

The limit of our data: St. Louis firm pages show no license status at all (100.0% unmatched). The City's business license search works one name at a time, not as a bulk file, and the trade boards publish no list of license holders, so we have nothing to match against. We also have no electrical, plumbing or HVAC pages for St. Louis: those permits sit in a separate City system whose bulk download is marked "Deprecated (and pre-Nov 28, 2018)" (Electrical Permits dataset). For those trades, the phone calls are the check.

Red flags on a St. Louis contractor

• No Graduated Business License, or a firm that does not show on the Business License Search for the current year. The license is required of subcontractors too.
• An electrician, plumber or drainlayer with no City license and, for electrical, no statewide license either.
• A request that you pull the permit yourself. In the City a homeowner electrical permit is only for an owner-occupied single-family home, after a short test, and "You may not apply for permits for service changes, rehab, or new construction."
• A tornado-zone firm showing a placard without the City Seal, or listed as "Submitted, not Verified", and describing itself as City-approved. The City says a listing "does not imply City endorsement or approval".
• No workers' comp certificate and no exemption affidavit.
• A business license from the wrong side of the line: a County town's license on a City job, or the reverse.

See every St. Louis remodeler by their permit record →