Colorado Plumbing Laws and Regulations

The Legal Framework

Colorado plumbing is governed by the Plumbers Practice Act, codified in Colorado Revised Statutes § 12-155. This statute establishes the State Plumbing Board within DORA's Division of Professions and Occupations, defines the license tiers, sets experience requirements, and gives the Board authority to adopt rules, administer exams, and take disciplinary action.

The Board's administrative rules are published as 3 CCR 720-1 through the Colorado Secretary of State. These rules fill in the operational details that the statute outlines — continuing education requirements, supervision definitions, experience verification procedures, and the adopted plumbing code (the International Plumbing Code and International Fuel Gas Code).

For working plumbers, the practical reality is that two layers of law apply to every job: the statute and Board rules at the state level, and local municipal codes and ordinances at the city or county level.

House Bill 24-1344: The 2025 Modernization

House Bill 24-1344 is the most significant update to Colorado plumbing regulation in recent years. It extended the State Plumbing Board's regulatory authority through 2032 and made several substantive changes effective July 1, 2025:

Title change: The intermediate license tier is now officially "Journeyworker Plumber" instead of "Journeyman Plumber." This language change applies throughout the Plumbers Practice Act. If you see old forms or references using "Journeyman," they're pre-2025 materials.

Three-year renewal cycle: Individual plumbing licenses are transitioning from a two-year renewal cycle (expiring in odd years) to a three-year cycle, effective March 1, 2027. The first three-year licenses will expire in 2030. Continuing education requirements adjust proportionally — 24 hours per three-year cycle instead of 16 hours per two-year cycle, maintaining the same 8 hours per year standard.

Backflow licensing: The bill mandates that anyone installing, testing, or repairing backflow prevention devices must hold a specific board-approved backflow license. This is a separate credential from standard plumbing licenses.

Vehicle and branding display: Effective June 30, 2025, all registered plumbing contractors must display their registration number and their designated master plumber's license number on all vehicles, websites, documents, and advertising.

The Supervision Framework

Colorado's supervision rules have been refined through multiple Board rule amendments. The current framework establishes specific requirements for apprentice oversight:

Direct supervision definition: Under Board Rule 1.2E, the supervising licensed plumber must be physically present at the permitted job address or located no more than five minutes' travel distance from the apprentice. Line-of-sight is not required, but immediate proximity is strictly enforced.

Supervision ratios: For commercial installations, the supervisor-to-apprentice ratio is determined per individual permit. For residential work, the ratio covers the permitted structure plus one platted lot on either side.

The six-year testing rule: Under C.R.S. § 12-155-124, any apprentice who has been registered for at least six years must sit for the state licensing exam at least once every two years. Failure to comply allows the Board to suspend the apprentice's registration, preventing them from working on any job site.

Self-Verification Prohibition

Under Board Rule 1.4 A(3)(f), applicants are strictly prohibited from verifying their own work experience. All experience hours must be verified by the supervising master plumber or registered plumbing contractor. This rule closes a loophole that previously allowed some self-employed applicants to validate their own hours.

If a previous employer is unreachable or refuses to sign an experience affidavit, alternative verification options include co-owners or office managers signing on company letterhead, or requesting verified hours from DORA's annual apprentice reporting database (contractors are required to report apprentice hours every January 1).

Criminal History and Licensing

Under House Bill 24-1004, prior criminal convictions do not automatically disqualify a plumbing license applicant. However, failure to disclose prior convictions on the application is grounds for immediate denial. The Board evaluates criminal history on a case-by-case basis, considering the nature of the offense, its relevance to plumbing work, and the time elapsed since the conviction.

Disciplinary Authority

The State Plumbing Board has broad disciplinary authority under the statute. Violations that can trigger action include:

• Performing plumbing work without a valid license
• Employing unregistered apprentices
• Violating supervision ratios or distance requirements
• Failing to display required identification numbers
• Allowing unlicensed individuals to perform work under your credential
• Submitting false experience affidavits

Penalties range from administrative fines and formal reprimands to license suspension or revocation. Job-site inspectors have the authority to conduct contemporaneous reviews under HB 19-1086 — meaning they can check credentials for every worker on-site during any standard inspection.

Staying Current

Colorado plumbing law is not static. The Board regularly updates its administrative rules, and the legislature periodically passes bills that modify the statute. Major changes like HB 24-1344 affect licensing timelines, renewal requirements, and operational compliance in ways that directly impact working plumbers.

The Colorado Plumber License Guide consolidates current state law, Board rules, and municipal requirements into a single process reference — updated to reflect the 2025 changes and the upcoming 2027 renewal transition.

See more Colorado guides →