1.2 Colorado Licenses, Experience Hours, and Apprentice Supervision

The statute, the board, and the word "journeyworker"

Plumbing in Colorado is regulated under the Plumbers Practice Act, C.R.S. Title 12, Article 155, administered by the Colorado State Plumbing Board inside the Division of Professions and Occupations (DPO) at the Department of Regulatory Agencies (DORA). The Board's rules are codified at 3 CCR 720-1; the version current as this guide is written took effect February 14, 2026.

Colorado no longer uses the word "journeyman" in its statute or rules. The license is a Journeyworker Plumber license, and the Board's own membership list, the rules and the PSI bulletin all use that term. You will still see "journeyman" in job postings and search engines, which is why this guide carries both.

C.R.S. 12-155-104(2)(a) sets the Board at seven governor-appointed members: one journeyworker plumber, one master plumber, two plumbing contractors, one general contractor, one local-government plumbing inspector and one public member, plus a non-voting ex officio representative of the Colorado Department of Public Health and Environment. At least one member must live on the Western Slope.

The four credentials and one registration

The hour figures come straight from C.R.S. 12-155-110(1)(a) and Board Rule 1.4(A)(3)(e). DPO converts one month of full-time experience to 163 hours.

Two points candidates routinely get wrong:

• You do not have to hold a residential license before testing for journeyworker. The classifications are separate entry points, not a mandatory ladder.
• A plumbing contractor registration is a business registration, not a license. C.R.S. 12-155-108(3) requires the contractor to be, or to employ full time, a master plumber who supervises all plumbing work, and to show evidence of compliance with Colorado's workers' compensation and unemployment compensation laws. A master plumber may be responsible for only one plumbing contractor at a time and must notify the Board within 15 days of terminating that role.

Substituting school and military service for field hours

Board Rule 1.4(A)(3) sets the substitution rules precisely, and the numbers are tested:

• Classroom training: one hour of classroom training equals one hour of on-the-job training, up to a maximum of one year, where 2,000 hours equals one year. The program must be an accredited high-school vocational technical course, community college or trade school program that runs not less than two years, and a transcript must accompany the application.
• Military training: credited at one month for every six months of training or experience, again up to a maximum of one year.
• Applicants cannot verify their own experience, even if they hold an out-of-state license. Verification comes from the master plumber or a signatory authority of the contractor, on Board forms, broken out by commercial, residential and industrial work in hours and months.

Apprentice registration and the 3:1 supervision rule

Any person working in the plumbing trade in Colorado who does not hold a Colorado plumbing license is a plumbing apprentice and must be registered. Two details carry citation exposure:

• The employer registers the apprentice, within 30 days after the date of initial employment (C.R.S. 12-155-108(2)(a) and (b)). Board Rule 1.3(A)(3) makes failing to register within 30 days a disciplinary matter for the employer, and Rule 1.3(A)(4) requires the employer to inactivate the apprentice within 30 days of termination.
• A residential plumber working on a commercial job site must be registered as an apprentice (Rule 1.3(A)(2)) — an easy trap for a crew that moves a residential licensee onto a commercial project.

The supervision ratio is one flat number:

C.R.S. 12-155-124(1): "One licensed journeyworker plumber, master plumber, or residential plumber shall not supervise more than three plumbing apprentices at the same job site."

There is no separate residential ratio and no separate commercial ratio. Three apprentices per licensed plumber, everywhere. The supervising licensee is responsible for the apprentice's work, and the licensee's own license can be suspended, revoked or denied for the apprentice's improper work (12-155-124(2)).

Board Rule 1.2(E)(1)(c) defines direct supervision as the supervising licensed plumber being physically present at the same physical addresses listed on the permits and where the apprentice is working, or no more than five minutes' distance from the apprentice within the same construction or job site. "Five minutes away on the same site" is compliant; "gone to the supply house" is not.

Worked ratio check

A commercial remodel has 2 journeyworkers and 1 master plumber on site with 9 registered apprentices.

• Licensed supervisors on site: 3
• Maximum apprentices: 3 supervisors x 3 apprentices = 9
• Result: compliant, exactly at the limit. Lose one licensee to a service call and the crew is over by three.

Board Rule 1.7(D)'s fine schedule prices the violation: supervising more than three apprentices at the same job site draws $375 for a first offense, $600 for a second, and up to $2,000 per day thereafter.

The apprentice examination requirement

Colorado is unusual in forcing long-term apprentices to test. Under C.R.S. 12-155-124(4), a plumbing apprentice who has been registered for at least six years, has completed 6,800 hours of practical training and meets the other license requirements must take the license examination at least every two years, aligned with the license renewal cycle, until passing. An apprentice who has failed in two consecutive two-year periods may request an exemption, and Board Rule 1.3(D) grants exemptions for documented military deployment. PSI publishes a separate blueprint for the six-plus-year apprentice examination; its content areas and item counts are identical to the Journeyworker exam.

Renewal, the 2027 cycle change, and continuing education

All Colorado plumbing licenses and registrations currently expire on the last day of February of odd-numbered years — a two-year cycle. C.R.S. 12-155-112(1)(a) provides that, beginning with the plumbing license cycle that starts March 1, 2027, the Board will issue and renew plumbing licenses for three years unless the director determines otherwise. Both statements are true; the difference is the effective date.

Continuing education is set by 12-155-112(3)(a) and Board Rule 1.4(E)(3):

• Eight hours of CE for every 12 months since the later of the last renewal or reinstatement.
• Within every 24-month period, at least four hours must be code hours and at most two hours may be safety training.
• CE hours come from the Board's core competencies: cross connection and backflow prevention; fixtures, faucets and fixture fittings; indirect/special waste; industry product training; non-potable water systems; plumbing administration; residential fire sprinkler systems; sanitary drainage; special piping (medical gas); storm drainage; system piping and components; traps, interceptors and separators; vents; water heaters; water supply and distribution; and safety.
• The first renewal after initial licensure by examination is exempt from CE.
• Licensees must attest at renewal that they have read the current Colorado Plumbing Code.
• There is a 60-day grace period after expiration with a delinquency fee; past that, reinstatement is required. A license expired more than two years requires proof of competency, which may mean retaking the state examination.