If you're a licensed contractor in California, Florida, Washington or Arizona, your state's rules say your license number belongs in your advertising. Florida's licensing board goes as far as naming “Internet sites.” So we checked. On October 18, 2026 we opened the websites of 869 roofers, HVAC companies, plumbers and general contractors that Google shows in 14 cities across those four states, and looked for a license or registration number.
603 of them show one. 266 don't. That's 3 in 10 (30.6 percent). And 155 of those 266 tell visitors they're “licensed” somewhere on the site without giving the number that would let a homeowner check.
Below are the four rules in each state's own words, how we ran the check, what we found by state, trade and business size, the mistakes we saw on sites that do show a number, and a fix that takes about ten minutes.
Four States Put It in Writing: Your License Number Goes in Your Ads
Here's what each state's text says. We're quoting it so you can read it yourself. This isn't legal advice, and your licensing board has the final word on how its rule applies to you.
| State | The rule | Does it reach your website? | What the text says about penalties |
|---|---|---|---|
| California | Bus. & Prof. Code 7030.5: your license number goes in “all forms of advertising, as prescribed by the registrar of contractors.” | The board's regulation, 16 CCR 861, counts “airwave or any electronic transmission” as advertising. | Not checked for this post |
| Florida | Fla. Stat. 489.119(5)(b): the number must appear in each “advertisement, regardless of medium.” | The board's rule, 61G4-12.011, lists “any electronic media including Internet sites.” | Not checked for this post |
| Washington | RCW 18.27.100(3)(a): “All advertising that shows the contractor's name or address shall show the contractor's current registration number.” | Yes, if it shows your name or address. Radio and TV (“airwave transmission”), vehicle signs and on-premises signs are carved out. | Up to $10,000, but not for “an inadvertent error” |
| Arizona | A.R.S. 32-1124(B): the number, “preceded by the acronym ROC,” goes on “all published advertising.” | Internet ads can skip it only if they link straight to “a website that prominently displays the licensee's name and license number.” | Grounds for discipline at the registrar's discretion. It doesn't void your contracts. |
Arizona's version is the one to read twice if you run online ads. An internet ad in Arizona can leave the ROC number off, but only when it links directly to a website that prominently shows your name and license number. So the page your ad sends people to is what carries the number for every click. If your Google Ads point at a landing page with no ROC number on it, the exception the statute gives online ads doesn't fit.
Trucks are where the states split. Florida says that if a vehicle carries your company name, or artwork that makes it look like a contracting vehicle, the number “must be conspicuously and legibly displayed” with it, though the same paragraph says it doesn't create a requirement to put signs on vehicles. Washington's statute says signs on motor vehicles don't count as advertising at all. California's regulation lists “lettering on vehicles” as advertising. Same industry, three different answers, which is why your own board's rule is the one to follow.
How We Checked 869 Contractor Websites, and What a Check Like This Misses
We ran 56 Google Places API text searches: four trades (roofing contractor, HVAC company, plumber, general contractor) in 14 cities. In California: Los Angeles, San Diego, Sacramento, San Jose and Fresno. In Florida: Miami, Tampa, Orlando and Jacksonville. In Washington: Seattle, Spokane and Tacoma. In Arizona: Phoenix and Tucson. We kept the top 20 results for each search, service-area businesses included. That gave us 1,120 results, 1,091 with a website, and 1,012 different websites.
For each site we opened the homepage and up to three more pages whose links pointed to about, contact, license or warranty pages. Any site that blocked a plain request, or where we found no number, got a second look in a real web browser, so text drawn in by scripts was counted too. A site counted as showing a number when a license word (Lic, License, CSLB, ROC, L&I, Registration and similar) sat right before an ID in that state's format, or when a Florida board prefix like CCC, CAC, CFC or CGC, or an Arizona ROC number, appeared anywhere.
Then we checked the checker. We read 60 randomly picked “shows a number” sites by hand and every one was a real license or registration number. We also read every “no number” site that had a license word near a run of digits, 93 sites in all. 8 of them did show a number in a format the pattern missed, like a Washington registration typed with spaces in it, and we counted those as showing one.
Know the limits before you read the results:
- We couldn't read 139 of 1,008 sites (13.8 percent). Bot-protection walls, a site that blocks visitors from outside the US (we ran this from Canada), parked domains and “under construction” pages. They're left out, not counted as missing.
- Four franchise brands are left out. One website serving locations in several states can't be scored against one state's rule.
- A number inside an image is invisible to a text check. We looked through the image descriptions and file names on every “no number” site and didn't find one, but a badge graphic can still hold a number we couldn't read.
- We read one to four pages per site. A number on a deeper page shows up here as missing.
- We didn't check whether any number is real or active. Only whether it's there.
- It's Google's top 20 on one day, not every contractor in those cities. And a site can rank for more than one trade, so the trade rows below add up to more than 869.
3 in 10 Contractor Websites Show No License Number
Here's the count by state. “Shows a number” means anywhere on the homepage or the extra pages we opened. 573 of the 603 sites that show one have it on the homepage itself.
| State | Websites checked | Show a number | Share | Show none |
|---|---|---|---|---|
| Arizona | 135 | 101 | 74.8% | 34 |
| California | 302 | 216 | 71.5% | 86 |
| Florida | 254 | 177 | 69.7% | 77 |
| Washington | 178 | 109 | 61.2% | 69 |
| All four | 869 | 603 | 69.4% | 266 |
Washington trails the other three by 8 to 14 points, even though its statute spells out a fine of up to $10,000. Arizona leads, and even there 1 in 4 sites we read show no license number at all.
By trade, general contractors are the outlier:
| Trade | Websites checked | Show a number | Share |
|---|---|---|---|
| Plumbers | 212 | 162 | 76.4% |
| HVAC companies | 219 | 162 | 74.0% |
| Roofers | 227 | 159 | 70.0% |
| General contractors | 232 | 138 | 59.5% |
94 of the 232 general contractor sites show no number. Plumbing and HVAC sites do best.
Business size tells the clearest story. We sorted the sites by how many Google reviews the business has, as a rough stand-in for size and age:
| Google reviews | Websites checked | Show a number | Share |
|---|---|---|---|
| 0 to 49 | 146 | 74 | 50.7% |
| 50 to 199 | 295 | 182 | 61.7% |
| 200 or more | 428 | 347 | 81.1% |
About half of the businesses with fewer than 50 reviews leave the number off. Among businesses with 200 or more reviews, 4 in 5 show it. That's a pattern, not proof of cause, but it means the contractors with the least reputation to lean on are the ones skipping the one credential a stranger can check.
What about Google rankings? Sites in the top three results of our searches showed a number 75.2 percent of the time, against 68.3 percent for positions 4 to 20. That gap is small, and we have no evidence that a license number moves your ranking. We're not claiming it does.
The finding that should sting most is the word without the number. 155 of the 266 sites with no number (58.3 percent) say “licensed” somewhere, and 137 say it on the homepage, usually as “Licensed & Insured” in the header. Anyone can type that word. The number is the part a homeowner can actually check.
Homeowners Are Already Looking You Up
People check. Google's Keyword Planner puts US searches for “cslb license lookup” at about 18,100 a month over the past year. “Contractor license lookup” gets about 9,900. “Verify contractor license” and “check contractor license” each get about 5,400.
Each of these states has a free public lookup: CSLB's Check a License in California, the DBPR license search in Florida, L&I's Verify a Contractor in Washington, and the Arizona Registrar of Contractors' contractor search. When your number is on your site, that check takes a minute and ends with your name on a state website. When it isn't, the homeowner has to search by business name and hope the record matches the name on your truck. Some won't bother, and you'll never know they looked.
It's also the cheapest trust signal you'll ever add. No reviews to collect, no ads to pay for. You already earned the license. The website just has to say it.
Is your number where your state wants it? Book a free 20-minute call. We'll check your homepage, footer and ad landing pages for the number your state asks for and tell you exactly what we'd change.
Book a Free Site Check →Five Mistakes We Found Besides a Missing Number
Putting something in the license spot isn't the whole job. Here's what else turned up. We're not naming any business.
- A placeholder. One Florida roofer's footer reads “License: 1A2B3456.” That's sample text from a website template that nobody replaced. We counted it as no number, because it isn't one.
- The wrong registration. One Florida site shows its fictitious-name (DBA) registration number where a license number would go. That number registers a trade name with the state. It isn't a contractor license.
- A business ID instead of a contractor number. 2 of the 109 Washington sites that show a number show a 9-digit number in the format of Washington's business ID, not the letters-and-digits contractor registration that most Washington sites show.
- No “ROC.” 4 of the 101 Arizona sites that show a number leave off the “ROC” the statute says must come before it.
- Buried on an inner page. 30 sites show the number only on an about, contact or license page. A homeowner who lands on your homepage from Google won't see it, and Arizona's online-ad exception asks for a site that “prominently displays” it.
The 10-Minute Fix
- Put the number in your site-wide footer as plain text, not inside a logo or a badge image. Text can be read by homeowners, by screen readers and by search engines. Use the format your state uses: “CSLB Lic. #” and your number in California, the full number with its board prefix (CCC, CAC, CFC, CGC and so on) in Florida, your L&I registration exactly as L&I lists it in Washington, and “ROC” followed by your number in Arizona.
- Put it next to “Licensed & Insured.” If your header already says licensed, add the number right after the word. That turns a claim into something a homeowner can check.
- Link the number to your state's lookup page. One click from your site to your record on the state's site.
- Check every page your ads send people to. Landing pages built for ads sometimes drop the normal footer. In Arizona, that page is what lets an online ad leave the number off.
- Check the rest of your advertising against your state's rule. Trucks, yard signs, quotes, business cards and mailers. The rules differ by state, so read your board's version rather than your neighbour's.
- Ask your board when you're unsure. Their answer beats any blog post, this one included.
If you'd like a hand, that free call is the place to start. We manage Google Ads and local SEO for contractors, and the page an ad sends people to is part of that job. We ran a similar website census on contractors still advertising an expired tax credit, and the lesson is the same: what your website says is advertising, and somebody reads it.
How we did this: On October 18, 2026 we ran 56 Google Places API text searches (4 trades, 14 cities in California, Florida, Washington and Arizona, top 20 each, service-area businesses included), opened 1,012 websites (homepage plus up to three about, contact or license pages, re-opened in a real browser when needed) and looked for a license or registration number in each state's format. 139 sites we couldn't read and four multi-state franchise sites were left out, for 869 websites in the final count. We read 60 positives and 93 borderline negatives by hand. We didn't check whether numbers are valid. Statute text was read on the state legislature sites and Cornell's Legal Information Institute on October 18, 2026.