Home › Guides › Do Plumbers Have to Show a License Number on Their Website?
Do Plumbers Have to Show a License Number on Their Website?
Short answer: Plumbers in many states have to show a license number in their advertising. Illinois, Texas and Iowa have written plumbing ad rules, and Florida, Nevada, Oregon and Washington require contractor numbers in ads and say so for websites. We could confirm no rule in other states. Even where it is optional, put your number in your footer.
- Illinois says all advertisements for plumbing services must include the plumbing license number.
- Texas ads must state the license number of the responsible master plumber of record, with listed exemptions.
- Iowa Code 105.25 requires the contractor license number in written ads, and claiming a license you lack is a misdemeanor.
- Florida, Nevada, Oregon and Washington list websites or internet ads among the advertising that must show the number.
- We did not find a rule in every state, so ask your own board.
- Put the number in plain text in the footer of every page, not inside an image.
A license number is the number your state or local board gave you when it licensed you or your business. For plumbers it is often a master plumber number, or a contractor number, depending on the state. Showing it proves you are allowed to do the work, and it gives a homeowner something to look up.
This page covers what we could confirm on official sources. Rules change, and many are written for "advertising" in general, so check with your own board before you rely on this. This is not legal advice.
Is a website "advertising" for a plumber?
Mostly, yes. If a page tells people you fix leaks and how to hire you, a regulator can treat it as an advertisement. Some boards say so outright. Florida's contractor FAQ defines "advertise" to include electronic media including Internet sites. Nevada's contractors board lists the website among the places a license number must appear (Nevada State Contractors Board). Oregon's rule says all advertising by internet media, including website advertising, must show the number visually.
Other boards use the words "all advertisements" and do not name websites. In that case, assume the website is covered. It costs you one line of text.
What do the states say? A quick table
These are states where we found a written rule and opened the official source. Plumbing is licensed in different ways in different states, so the rows below use the rule as it is worded.
| State | What the source says | Source |
|---|---|---|
| Illinois | All advertisements for plumbing services must include the plumbing license number. | Illinois Department of Public Health |
| Texas | Ads that solicit plumbing business must state the license number of the responsible master plumber, in any media, with listed exemptions. | 22 TAC 367.10, Cornell LII |
| Iowa | All written ads distributed in the state must include the contractor license number, as applicable. Claiming a license you lack is a simple misdemeanor. | Iowa Code 105.25 |
| Florida | Certified and registered contractors must show the number on advertisements, including Internet sites, and on vehicles that display the business name. | Florida DBPR |
| Nevada | All forms of business advertising must show the number. The board lists websites, vehicles and online directories. | Nevada State Contractors Board |
| Oregon | Website and other internet ads must show the number visually. | OAR 812-003-0120 |
| Washington | You must include your contractor registration number when you advertise, including internet ads, estimates and bid proposals. | Washington L&I |
That is not the full list. Some states we checked had no advertising rule we could find, and others license plumbers at the city or county level. "We did not find one" does not mean none exists, so ask your board.
Illinois: the plumbing-specific rule
Illinois is the clearest plumbing case. The state health department licenses plumbers and apprentice plumbers, and its plumbing page says that all advertisements for plumbing services must include the plumbing license number. Put the number in your footer on every page, and on your truck, cards and estimates. See our Illinois page for more on how licensing works there.
Texas: the number of the master plumber of record
Texas ties the number to the responsible master plumber, not to a company. The Board's advertising rule says ads designed to solicit plumbing business must state the license number of the responsible master plumber of record, whatever the media (22 Tex. Admin. Code 367.10). The rule lists exemptions, including promotional items of nominal value such as caps and T-shirts, signs at the business location, and listings the company does not control or edit.
The rule text we read does not speak specifically about a plumbing company's own website. A website that sells your services reads as an ad, so we suggest the number goes on it. The rule also has a separate list of items for proposals, invoices and contracts, so check what your documents must carry. We keep a page for Texas.
Iowa: written advertisements
Iowa Code section 105.25 covers advertising by contractors in plumbing, mechanical, HVAC, refrigeration, sheet metal and hydronic work. Its rule says all written advertisements distributed in the state must include the contractor license number, as applicable. The same section says that only a person duly licensed may advertise as licensed, and that claiming a license you lack, or listing a false number, is a simple misdemeanor (Iowa Code 105.25). The passages we read name the misdemeanor for false claims, not for leaving the number off. Our Iowa page has more.
Florida, Nevada, Oregon and Washington: contractor numbers in ads
These four use broader contractor rules. If you hold a state contractor license or registration there, your number goes on your advertising, and each state lists websites or internet ads. Florida adds a vehicle rule: the number goes on any vehicle that displays the contractor's name, and promotional novelties such as pens, hats and shirts are not treated as advertising (Florida DBPR). Check whether plumbing falls under the contractor board in your state or a separate plumbing board, because that decides which number you list.
What if my state has no rule?
We did not find an advertising rule in every state, and we cannot rule out a city or county rule. Put your number on the site anyway:
- Homeowners can look you up and see you are real.
- It separates you from unlicensed people working off a phone number.
- Google and AI assistants read your page for facts. A license number in plain text is something they can quote.
- If a city or county adds a rule, you are already covered.
Our own advice, not a legal rule: if you hold several licenses, list the one that covers the work you advertise.
Does the rule cover Google, social media and flyers?
The rules we read say "all advertisements," "all forms of advertising," or list items such as websites, vehicles and cards. None of the pages we opened named Google Business Profile or social media. That gap is not permission. If you run a Facebook page or a Google profile that sells your services, treat it like any other ad and put the number there as well.
A simple habit works. Wherever your business name appears with an offer to do plumbing, the number goes next to it: site, profile, truck, cards, estimates and flyers. Check the exemptions in your state before you print it on hats.
What happens if you leave it off?
It depends on the state. Iowa's section lists a simple misdemeanor for false claims, not for omission. The Texas, Illinois, Florida, Nevada and Washington pages we read do not state a penalty for omission in the passages we opened. Whatever the penalty, a complaint to your board is a headache one line in your footer avoids.
What if you are not licensed yet?
Do not advertise as a licensed plumber. A license number you do not hold is the worst thing you can put in a footer. In Illinois, for example, the state says people who plan, install, alter, repair and maintain plumbing systems must be licensed. Work under a licensed plumber and check your board's steps for an apprentice or journeyman card.
How do you add your license number to your plumbing website?
Do these five things. They take under an hour on most sites.
Step 1: Find your exact number and name
Look yourself up on your state board's license search. Copy the number and the business name exactly as they appear. Some rules say the name must match.
Step 2: Put it in the footer of every page
Write "Licensed Plumbing Contractor, License #12345" in plain text, not in a picture. Search engines and AI tools read text. They cannot read a logo. In Texas, make sure it is the number of the master plumber of record.
Step 3: Add it to the contact page, the about page and your service pages
People look for it there. Say who holds the license and what it covers. A water heater or sewer page is a good place for it, since those are higher-ticket jobs. See water heater installer marketing.
Step 4: Match it everywhere else
Use the same number on your Google Business Profile, trucks, estimates, invoices and cards. Our Google Business Profile tips for plumbers show where it fits.
Step 5: Link to the board lookup
If your board has a public search, link to it. "Verify our license" with a link to the state page gives a nervous homeowner a way to check. For more to put on your site, see what a plumbing website should include.
Does the license number help you get calls?
We have no data that says it adds leads, so we will not claim it. What it does is answer a question homeowners ask before they dial: "Is this person licensed?" In a Scorpion survey, 83% of homeowners said they start their search online (ACHR News, Scorpion report (2026)). They compare options on screen, and a clear license line is an easy thing to check. For the buyer's side, see the hub guide on how to know if a contractor is legit.
Pair it with a strong local profile and good reviews, covered in plumber SEO. To get a footer with the license line built in, you can see a free demo site.
Common questions
Do I have to show my plumbing license number on my website?
It depends on your state. Illinois, Texas and Iowa have plumbing or contractor advertising rules, and Florida, Nevada, Oregon and Washington say websites or internet ads count. In states where we found no rule, we still suggest putting the number in your footer. Check your board for the latest wording.
Where should the license number go on the page?
In the footer of every page, in plain text. Add it on your about and contact pages too. Do not put it only in an image, because search engines and AI tools cannot read text inside a picture.
Does my license number need to be on my truck and invoices too?
In some states, yes. Florida requires it on vehicles that display the contractor's name. Texas lists separate items that proposals, invoices and contracts must carry. Check your own board for the full list, and put the number anywhere a customer sees your business name.
Which number do I show, the master plumber or the company?
It depends on the state. Texas ties advertising to the license number of the responsible master plumber of record. Other states license the company. Read your board's wording, or call it, and show the number the rule names.
What if I work in more than one state?
Follow the rule of each state where you work and list each license on your site. A page for each state, with that state's number, keeps it clear.
Sources
- Illinois Department of Public Health: Plumbing (2026)
- Cornell LII: 22 Tex. Admin. Code 367.10, Display of RMP name and license number (2026)
- Iowa Legislature: Iowa Code chapter 105, section 105.25 (2026)
- Florida DBPR: Construction industry FAQs (2026)
- Nevada State Contractors Board: Advertising requirements (2026)
- Cornell LII: Oregon Administrative Rules 812-003-0120 (2026)
- Washington Department of Labor and Industries: Register as a contractor (2026)
- ACHR News: Scorpion industry report (2026)
We build your new website free, before you pay, then work every week to get you named when homeowners ask Google and AI who to call. Get your free demo site.