Colorado licenses plumbers statewide through the State Plumbing Board: residential at 3,400 hours, journeyworker at 6,800, master at 8,500, with an exam-first application process, a 30-day apprentice registration deadline, 8 CE hours per year, and a rule that shuts a plumbing contractor down 20 days after it loses its responsible master plumber. The full 2026 ladder, the HB 24-1344 changes, and where the master license turns into a business.
Colorado is one of the states that licenses plumbers statewide, a meaningful contrast with its approach to general contractors, who are licensed city by city with no state GC license at all. If you want to work as a plumber anywhere in Colorado, your path runs through the Colorado State Plumbing Board, part of the Division of Professions and Occupations (DPO) inside the Department of Regulatory Agencies (DORA) in Denver. The board has been regulating the trade since 1917.
The ladder has three license tiers, residential plumber, journeyworker plumber, and master plumber, sitting on top of a registered apprenticeship. This guide walks the whole path: the exact hour requirements from the board's rules, the exam-first application process that surprises out-of-state plumbers, the 2024 law that renamed the journeyman tier, the continuing education clock, and what it takes to turn a license into a plumbing business at the top of the ladder.
The Colorado Plumbing License Ladder at a Glance
Colorado's rules (3 CCR 720-1, as revised effective April 2025) set the practical experience required to qualify for each license:
| Credential | Practical experience required | What it allows | |---|---|---| | Plumbing apprentice (registration) | None, register within 30 days of employment | Plumbing work under supervision | | Residential plumber | 3,400 hours | Residential plumbing work | | Journeyworker plumber | 6,800 hours | Residential and commercial plumbing work | | Master plumber | 8,500 hours | All plumbing work, including planning, layout, and supervision |
Two details worth flagging. First, the hour thresholds are also written into the statute: section 12-155-110 of the Colorado Revised Statutes caps what the board may require at 6,800 hours for journeyworker and 8,500 for master, so these numbers are stable by law. Second, "journeyworker" is not a typo, House Bill 24-1344, the 2024 sunset bill that extended the Plumbing Board through 2032, replaced the term "journeyman plumber" with "journeyworker plumber" throughout Colorado law. You will still hear both on job sites, but the license in your pocket now says journeyworker.
Step 1: Register as a Plumbing Apprentice
There is no apprentice license in Colorado, but registration is mandatory and the deadline is tight: your employer must register you with the board within 30 days of employment, per section 12-155-108(2)(a). Employers who miss the window, or who fail to inactivate a departed apprentice within 30 days, face disciplinary action.
While registered, you work under the supervision of a licensed plumber for a registered plumbing contractor, and the recordkeeping burden sits mostly on your employer: supervising contractors must maintain employment records documenting your hours and exact dates of employment, and must hand those records over when you request them or leave. The board also runs an annual apprentice experience reporting process. Keep your own copies of everything, when you apply for a license, you will need documented, verified evidence of your hours.
One rule that catches people: a licensed residential plumber working on a commercial job site must also hold an active apprentice registration and be supervised accordingly. Your residential license does not cover commercial work on its own.
Step 2: Build Your Hours (and Shortcut Options)
The board's rules allow two substitutions for field experience, each capped at one year:
- Trade school or vocational education: one hour of classroom training in an accredited program (minimum two years long) counts as one hour of on-the-job training, up to a maximum of one year, with 2,000 hours equaling one year. Transcripts must come from the school.
- Military plumbing training: one month of credit for every six months of training or experience, up to a maximum of one year.
Everything else is field time, and note that the board's rules exclude some work from qualifying. Document your employment history carefully, because your application must include written evidence verified by the master license holder or registered plumbing contractor you worked under.
Step 3: Pass the Exam, Before You Apply
Colorado runs its licensing sequence in the opposite order from many states: under board rule 1.4, candidates must pass the required examination before submitting an application to the board with their experience documentation. You test first, then apply for the license with your passing score and your verified hours.
Exams for all three tiers are administered by PSI Services and are based on the plumbing codes adopted by the board. The current exam formats, reference lists, and exam fees are published in PSI's Candidate Information Bulletin, check it before scheduling, because formats and fees are set by the vendor and change. Results come back pass/fail, and the exams are not subject to review after the fact.
A code-cycle note for 2026: the Plumbing Board held a rulemaking hearing in June 2026 on revisions to its standards rule to implement the new editions of the International Plumbing Code, Fuel Gas Code, and International Residential Code. If you are scheduling an exam, confirm which code edition PSI is testing against when you register.
Step 4: Apply Through DORA
With a passing exam score and documented hours, you apply to the board through DORA's online licensing portal. Application and license fees are set by the Division of Professions and Occupations and adjust periodically, so verify current amounts on the DPO plumbing pages before filing. Incomplete applications are held for one year and then discarded, after which you start over, including the fee.
Out-of-state plumbers may qualify for licensure by endorsement under section 12-155-116 if they completed a state or federally approved apprenticeship program (or equivalent years of experience), passed a comparable state plumbing exam based on a current or previous board-adopted code edition, and hold an active license in the endorsing state.
Step 5: Keep It Current, CE Every Year
All residential, journeyworker, and master plumbers with an active Colorado license must complete at least 8 hours of continuing education during each year of the license period, measured March 1 through February 28, the CE clock follows the licensure year, not the calendar year. Plumbers who earned their initial license by examination are exempt until after their first renewal. Courses only count if taken through providers who have attested to the board that their courses meet board rule.
Under HB 24-1344, the license renewal period is scheduled to lengthen from the current cycle to three years beginning in 2027, worth confirming with the board as the transition arrives.
Letting a license go inactive has real teeth: reactivating after less than three years requires 24 hours of CE completed in the preceding three years, while a license inactive for more than three years generally means retaking the state exam or verifying equivalent active licensure elsewhere. Practicing on an inactive license is treated as unlicensed practice.
The Top of the Ladder: Master Plumber and the Plumbing Contractor Registration
The master plumber license, 8,500 documented hours plus the master exam, is where the trade becomes a business. A master plumber has the qualifications to plan, lay out, install, and repair plumbing systems and to supervise others doing that work.
But here is the structural point most guides miss: a plumbing business in Colorado is a registered plumbing contractor, and every plumbing contractor must have a responsible master plumber. The board's rules make the dependency brutally clear. If a plumbing contractor loses the services of its responsible master plumber for any reason, it has twenty days to hire another master. Miss that window and the contractor registration is placed into what the rules literally call "Need Master Hire-Cannot Practice" status, the business is shut down for plumbing work until a new master is hired and the fee is paid.
HB 24-1344 tightened the public side of this relationship too: since mid-2025, plumbing contractors must display their registration number and the license number of their responsible master plumber on vehicles, billing materials, bid sheets, and their website. The responsible master is not a formality in Colorado, the state prints that person's number on the side of the truck.
(The same pattern repeats elsewhere in the rules: a water conditioning contractor must "be or employ full time" a registered water conditioning principal, with its own 20-day replacement clock. Colorado consistently ties the business's right to operate to a qualified individual's full-time presence.)
What If You Don't Have a Master Plumber?
This is where The Licensing Company comes in. If you are building a plumbing business in Colorado, or you are a contractor whose responsible master just gave notice and the 20-day clock is running, you need a master plumber employed in the business, and you need it fast. We place qualifying individuals as full-time W-2 employees of contracting businesses; that employment relationship is exactly what Colorado's responsible-master structure requires, and it is the only arrangement we place, in Colorado or anywhere else. Renting a number from a master who never sets foot in your operation is the kind of arrangement licensing boards exist to catch, we explain why in is it legal to rent a contractor license?
Start with what a qualifying agent is, then hire a qualifying agent when you are ready. And if you are a Colorado master plumber whose license could anchor a growing business, becoming a qualifying agent may be the most valuable thing you do with it.
Frequently Asked Questions
How long does it take to become a licensed plumber in Colorado?
Roughly 2 years of full-time work to reach the residential tier (3,400 hours), about 3.5 years for journeyworker (6,800 hours), and 4-5 years for master (8,500 hours), faster if you claim the one-year trade school or military credit. Add time for exam scheduling and application processing.
How much does a Colorado plumbing license cost?
The state's application and license fees are set by DPO and adjust periodically, and PSI's exam fees are set by the vendor, verify both on the DPO plumbing pages and in PSI's Candidate Information Bulletin before you file. The bigger cost question for business owners is what it takes to employ a responsible master plumber; that varies with your situation, and our consultation packages are built to answer it for your specific case.
Is there a separate plumbing contractor license?
Plumbing businesses register with the board as plumbing contractors, and the registration is only valid while the company has a responsible master plumber, with a 20-day replacement window if the master leaves.
Does my Colorado journeyworker license work in other states?
Colorado offers endorsement into its own licenses for qualifying out-of-state plumbers, and some states will evaluate Colorado experience, but every state sets its own rules. See our journeyman vs master plumber explainer for how the tiers compare nationally, and our state directory for each state's requirements.
Who regulates plumbers vs electricians vs general contractors in Colorado?
Plumbers and electricians are licensed statewide by their respective DORA boards. General contractors have no statewide license and are regulated by each city and county. Full picture: our Colorado contractor licensing guide.
Hour requirements, rules, and statutes cited are current as of August 2026, drawn from 3 CCR 720-1, Title 12 Article 155 C.R.S., and the Colorado State Plumbing Board. Fees are set by the board, DPO, and PSI and change, verify everything with the board (dora_plumbingboard@state.co.us, 303-894-7800) before applying.
Disclaimer: This article is provided for educational and informational purposes only. It does not constitute legal advice, licensing guidance, or an offer of services. Licensing requirements vary by jurisdiction. For specific compliance questions, contact The Licensing Company for a confidential consultation.