What to put on a plumbing cargo van
- The master plumber's license number in the form your state requires Texas wants M, MPL or RMP plus the number on both sides; California wants name, address and license number on each side at 1 1/2 inches; Illinois wants the displayed license number with the plumbing identification. The verified rules are below with citations.
- 'Plumbing' and '24-hour emergency' with the phone number, biggest A burst pipe at midnight is the most urgent call in home services. The number has to be readable from a car at night.
- Drain cleaning · Water heaters · Repiping · Leak detection Homeowners search the problem, not the trade. The list matches the search.
- 'Licensed · Bonded · Insured' with the number Plumbing permits and inspections make customers ask. Answer on the van.
- Water heater / tankless brands you install Brand names on the van pull the replacement job.
- Unit number and a review QR on the rear doors The rear doors face the street at every job; reviews and unit numbers both live there.
Layout by zone: driver door, side, rear
Example text for a plumbing business (a made-up company; 555 numbers are placeholders). Real text, so you can read it the way a customer would.
Driver / passenger doors
Riverbend Plumbing
RMP-00000 / state license no. as required
555-0147
Side panels
PLUMBING · DRAIN CLEANING · WATER HEATERS
24-hour emergency service · Repiping · Leak detection
Licensed & insured · 555-0147
Rear
Leak? Call 555-0147 · 24 hours
Scan for reviews
Unit 5
Do you need DOT numbers on a plumbing cargo van?
A plumbing van is heavy for its size: copper and PEX, fittings in steel bins, a drain machine or jetter, water heaters on the way to a job, and often a 500-lb-plus trailer-mounted jetter behind it. Service vans still usually sit under the federal marking line, but a van towing a jetter trailer is a combination and the combined rating counts. Check the GVWR sticker and the trailer rating; the checker does the rest.
The federal rule (from the same verified data as our checker): name and USDOT number on both sides of the power unit from 10,001 lbs (49 CFR 390.21T(b)(2)); other triggers in the federal box below.
The federal baseline, the same in every state
- USDOT Number + Legal / Trade Name, both sides of the power unit (49 CFR 390.21T(b)(2); 49 CFR 390.21T(b)(1))
- Readable from 50 feet in daylight, no inch minimum · sharp contrast
- MC Number: recommended, not required (49 CFR 390.21T)
- Triggers: 10,001 lbs or more · placard-level hazmat · 9+ passengers for hire · 16+ passengers
Verified 2026-07-23 · next review 2026-10-21
Answer 7 questions for your own vehicle
Check your state: California · Florida · Georgia · Massachusetts · New Jersey · Ohio · Texas · Washington · West Virginia. All 50 states.
Plumbing vehicle rules by state, verified
These are the plumbing vehicle-marking rules we have read in the state's own statute or regulation. States not listed: we have not verified a rule for them (our research notes list which ones were checked).
California: Plumbing contractors (C-36)
| Applies when | The business holds a California C-36 plumbing contractor license and the vehicle is commercially registered. |
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| On the vehicle | Name, permanent business address and contractor's license number on EACH SIDE of each commercially registered vehicle, letters and numerals at least 1 1/2 inches high. |
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California plumbers get a stricter rule than other trades: name, business address and license number on both sides of every commercially registered truck, at least 1 1/2-inch letters. Skipping it is grounds for discipline.
Legal source · verified 2026-10-18 · next review 2027-04-16
- Cal. Bus. & Prof. Code § 7029.5 (leginfo.legislature.ca.gov, full text read 2026-10-18): B&P 7029.5 — 'Every C-36 plumbing contractor, C-45 sign contractor, and C-57 well-drilling contractor licensed under this chapter shall have displayed on each side of each motor vehicle used in his or her business, for which a commercial vehicle registration fee has been paid ..., his or her name, permanent business address, and contractor’s license number, all in letters and numerals not less than 11/2 inches high. ... Failure to comply with this section constitutes a cause for disciplinary action.' (Amended by Stats. 2011, Ch. 432, Sec. 9. (SB 944) Effective January 1, 2012.)
Florida: Licensed contractors (Ch. 489 Part I: building, roofing, HVAC, plumbing, pool/spa and the other construction categories)
| On the vehicle | The registration or certification number must be conspicuously and legibly displayed with that name, text or artwork. Vehicle signage itself is not mandatory; local governments may add a competency/license number requirement. |
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Legal source · verified 2026-10-18 · next review 2027-04-16
Illinois: Plumbing businesses
| Applies when | An Illinois person or firm advertises plumbing services and has plumbing identification on its vehicles. |
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| On the vehicle | The license number of the licensed plumber displayed at the place of business must also be included with the plumbing identification on vehicles. |
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Illinois plumbing companies that put plumbing identification on the truck must include the displayed plumber's license number with it; missing it is a Class A misdemeanor with a $1,000 fine, each day a separate offense.
Legal source · verified 2026-10-18 · next review 2027-04-16
Nevada: Licensed contractors (NSCB)
| On the vehicle | The licensee's name and license number on each commercial motor vehicle registered under the licensee's name, letters and numbers approximately 1 1/2 inches high. |
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Legal source · verified 2026-10-18 · next review 2027-04-16
Ohio: Specialty contractors licensed under ORC Chapter 4740 (HVAC, refrigeration, electrical, plumbing, hydronics)
| On the vehicle | The license number, shown as 'OH LIC#-----', prominently placed on at least two sides of the vehicle, at least 2 inches high. |
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Legal source · verified 2026-10-18 · next review 2027-04-16
Texas: Plumbing companies
| Applies when | A Texas plumbing company (Responsible Master Plumber of record) operates or uses a service vehicle for plumbing work. |
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| On the vehicle | The RMP's license number, preceded by 'M', 'MPL' or 'RMP', and the company name on both sides of all service vehicles, on the body of the vehicle, contrasting color, at least 2 inches high. |
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Texas plumbing trucks carry the company name and the master plumber's number written as M, MPL or RMP plus the number, on both sides, at least 2-inch contrasting letters, on the body (not a magnet on the window).
Legal source · verified 2026-10-18 · next review 2027-04-16
Recommended set for a plumbing business
Mistakes plumbing owners make with vehicle lettering
- Writing the license number without the prefix the state requires. Texas enforcement looks for M, MPL or RMP in front of the number.
- Magnetic or window-mounted license numbers where the rule says on the body of the vehicle.
- Letters under the state minimum. Two inches in Texas, 1 1/2 in California: measured on the cut letters.
- 'Plumbing & heating' in a font nobody can read at night. Emergency trades need block letters and contrast.
- No emergency line. If you answer at 2 a.m., the van should say so; if you don't, say the hours.
Plumbing vehicle lettering FAQ
Does my state require the plumbing license number on the van?
Texas, California, Ohio and Illinois each have a rule we quote below, and the formats differ (a prefix in Texas, name-address-number in California). Several do, with specific formats. States we have not read are not listed, on purpose.
What's the right form for the number?
Whatever the rule says: in Texas the RMP number with M, MPL or RMP in front; in California the name, business address and license number on each side; in Ohio OH LIC# plus the number where the van shows the business name. The proof shows it in that form with the citation.
Does a plumbing van need a USDOT number?
Only if it crosses the federal weight line or your state's intrastate rule, which is a GVWR and towing question. A van towing a jetter trailer is the common case worth checking in the checker above.
Can you cut the license number separately from the advertising?
Yes. The license set is cut to the rule's size and color as its own piece, so it stays readable and compliant even if you change the advertising lettering later.
Do you do plumbing fleets?
Yes. Matched vans with the license number, unit numbers and the same fonts and colors, fleet pricing from 15 vans. Send the list of units and we cut it in one run.
More than one vehicle?
Fleet pricing from 15 vehicles, matched layouts across every unit, unit numbers included, one proof for the whole batch.
See fleet & volume pricing →
General information, not legal advice. Each rule above shows the date we last verified it against the cited source; the state agency has the final word.
