In the three states below, yes, your license number has to go in your advertising, and one of the three says the word website in the statute itself. Your own state writes this rule though, so the wording that binds you is the one you have to go and read.
Three states that put it in writing
California is the shortest. Business and Professions Code section 7030.5, on the California Legislative Information site, says every person licensed under that chapter “shall include his license number in: (a) all construction contracts; (b) subcontracts and calls for bid; and (c) all forms of advertising, as prescribed by the registrar of contractors, used by such a person.” The line under it reads “Amended by Stats. 1973, Ch. 153.” That page carries no update date.
Read those last words again. “As prescribed by the registrar of contractors” hands the detail to someone else. Section 7011 of the same code makes the registrar the executive officer of the Contractors State License Board. The code section itself never says the word website, so how the number has to appear on yours is a board question, not a statute question.
Florida is broader. Florida Statutes section 489.119(5)(b), in the 2025 Florida Statutes on the Florida Senate site, says “The registration or certification number of each contractor shall appear in each offer of services, business proposal, bid, contract, or advertisement, regardless of medium, as defined by board rule, used by that contractor or business organization in the practice of contracting.” Three words there do the work: regardless of medium. Paragraph (5)(d) then says that for this part, the term advertisement does not include business stationery or promotional novelties such as balloons, pencils, trinkets or articles of clothing. That page carries no update date.
Minnesota is the plainest of the three, and the narrowest. Minnesota Statutes section 326B.87, on the Office of the Revisor of Statutes site, is titled “LICENSE NUMBER; ADVERTISING.” Subdivision 2 reads: “The license number of a licensee must appear in any advertising by that licensee including but not limited to signs, vehicles, business cards, published display ads, flyers, brochures, websites, and Internet ads.” It names websites outright.
Read who it covers, though. Section 326B.802 defines a licensee, for sections 326B.802 to 326B.885, as a residential building contractor, residential remodeler, manufactured home installer or residential roofer. So the plainest wording in the country sits in a part of the code that is not every licensed trade in the state. The history line under 326B.87 reads “1991 c 306 s 19; 1995 c 169 s 5; 2007 c 140 art 8 s 21,30; art 13 s 4.” That page carries no update date.
What happens if you leave it off
Florida spells out a sequence you can go and read for yourself. Section 489.119(5)(e) says the board “shall issue a notice of noncompliance for the first offense, and may assess a fine or issue a citation for failure to correct the offense within 30 days or for any subsequent offense.” So a first miss is a warning, and the clock running after that warning is 30 days.
California and Minnesota keep their penalties in other parts of their own codes. Neither of the two sections quoted above names an amount. Do not take a dollar figure off a blog for this one. Call your board and ask.
This is not legal advice. Your state licensing board, or an attorney licensed in your state, is the only place to settle what your own license requires of you.
Nobody tells you what size to make it
Here is the honest limit in everything above. None of those three sections says where on the page the number goes, or how large it has to be.
The one piece of size language sits in Florida’s paragraph (5)(c), and it is about trucks. If a vehicle bears the name of a contractor, or text or artwork that would lead a reasonable person to believe the vehicle is used for contracting, the number must be “conspicuously and legibly displayed with the name, text, or artwork.” The same paragraph then says nothing in it creates a mandatory vehicle signage requirement. No matching line for a web page appears anywhere in that section.
So if a web company tells you there is a required font size or a required spot on the page, ask them to send you the line they are reading. Legible and easy to find is a standard you can defend to anyone. A pale gray line nobody can read is the version that looks like hiding, and low contrast text is one of the things an ADA accessibility check looks at anyway.
Where to put it
The footer is the right home for it. A footer repeats on every page, so one edit covers the whole site at once.
- The footer, sitewide.
- The contact page, next to the phone number.
- Your Google Business Profile, your social profiles, and any paid ad. If you have lost owner access to that profile, getting it back comes before editing it.
- Estimates, invoices and contracts. Minnesota’s subdivision 1 and California’s clause (a) both name contracts, not just ads.
Put the state next to the number. “License #123456” tells a homeowner nothing on its own. “CA License #123456” can be checked on the board’s public lookup. If you hold licenses in two states, or in two trade classes, list them all.
If a new site is being built for you right now, ask for that line in the footer template before launch instead of as a paid change afterward. Any website build should treat it as part of the job.
What this will not do for you
Adding your license number is a compliance job, not a ranking job. Anyone selling it to you as search work is charging a marketing price for a text edit. Ranking, and getting named in AI answers, is separate work, and it turns on what ChatGPT reads on your pages. That is what search checks cover, and they do not begin with a footer line.
Do not buy anything to fix this. On most sites it is a text edit that takes a couple of minutes.
The blocker is usually access, not wording. If the login sits with the company that built the site, and every change is billable, a two minute edit turns into a quote. That is a contract problem wearing a licensing costume, and getting out of an agreement that renews itself is the half worth sorting out first.
What to do next
- Open your own state board’s website and search it for the word advertising. Read the rule itself, not a summary of it. California, Florida and Minnesota above are examples, not your rule.
- Pull your exact license number and your exact business name from the board’s public lookup. Copy both of them character for character. A number that does not match the name on file is worse than no number.
- Add it to the footer, the contact page, and your estimate template today.
- If you cannot get into your own site to do it, deal with that first. The licensing question is the small half of that problem.
- If you are still unsure whether your ads comply, call the board and ask. The answer comes from the same people who would send the notice.