Colorado plumbers are licensed at the state level by the Colorado State Plumbing Board, a division of the Department of Regulatory Agencies (DORA) — not by individual cities or counties. To work as a plumber anywhere in Colorado, you must hold a Residential, Journeyworker, or Master Plumber license issued by the state, built on a foundation of registered apprenticeship experience, a passing exam score, and (if you want to run your own plumbing business) a separate Plumbing Contractor registration. This guide walks through each license tier, the experience and exam requirements, current fees, and what Denver and other cities layer on top of the state license.
Do You Need a Plumbing License in Colorado?
Yes. Colorado requires a state-issued license to work as a plumber, administered by the Colorado State Plumbing Board (DORA). This is a genuinely statewide requirement — it applies the same way in Denver, Colorado Springs, or any rural county. Individual municipalities may layer their own additional local certificates on top of the state license (Denver is the most prominent example, covered below), but the state license itself is the non-negotiable baseline everywhere in Colorado.
Colorado Plumbing License Tiers
The Colorado State Plumbing Board issues three individual license tiers, plus a separate business-level registration for plumbing contractors:
- Residential Plumber License — entry-tier individual license, scoped to residential work.
- Journeyworker Plumber License — the general working-plumber tier, covering both residential and commercial/industrial work.
- Master Plumber License — the senior tier; required to supervise apprentices and to serve as the "responsible individual" for a Plumbing Contractor registration.
- Plumbing Contractor (business registration) — required to operate your own plumbing business; must hold or employ a licensed Master Plumber as the company's responsible party.
Before any of these, anyone working in the trade without a license must be registered as a Plumbing Apprentice.
Registering as a Plumbing Apprentice
Most plumbers begin as apprentices. Basic eligibility requires being at least 18 years old, holding a high school diploma or GED, and having a valid driver's license.
- Find an employer. You must work for a plumbing contractor actively registered with the Colorado State Plumbing Board — either through a formal apprenticeship program (e.g., Emily Griffith Technical College, Red Rocks Community College, or a union program like Plumbers Local Union 3) or direct on-the-job placement.
- Register within 30 days. Your employer must register you as an apprentice with DORA within 30 days of your hire date, and pay the apprentice registration fee (currently $30).
- Carry your registration card while working, and accumulate verifiable, supervised experience toward your target license tier.
An apprentice must remain registered until they hold a full, unrestricted Colorado plumbing license.
How to Get a Residential Plumber License
- Accumulate experience: two years (approximately 3,400 hours) of documented practical plumbing experience under a licensed plumber, verified through Affidavit of Experience forms from current or former employers.
- Study for the exam: the Residential Plumber exam covers the International Plumbing Code (IPC) and International Residential Code (IRC) as adopted by Colorado, including water supply, vents, fixtures, drainage, and residential fire sprinkler topics.
- Submit your application to the State Plumbing Board with proof of experience, citizenship, and required screening questions, and pay the application fee (currently $100).
- Pass the exam: administered by PSI Services LLC — 100 multiple-choice questions, a 240-minute time limit, and a 70% passing score. The exam is typically open-book.
How to Get a Journeyworker Plumber License
- Accumulate experience: four years (approximately 6,800 hours) of documented practical plumbing experience — residential experience counts toward this total.
- Study for the exam: the Journeyworker exam covers a broader range of IPC/IRC topics than the Residential exam, including piping support, traps, storm and sanitary drainage, indirect/special waste, and isometric analysis.
- Submit your application with the same supporting documentation as the Residential tier, and pay the application fee (currently $120).
- Pass the exam: 100 multiple-choice questions, 240-minute limit, 70% passing score, administered by PSI Services LLC.
How to Get a Master Plumber License
- Accumulate experience: five full-time years (approximately 8,500 hours) of documented practical plumbing experience, inclusive of all prior tiers. One month of full-time work is credited as 163 hours.
- Study for the exam: the most comprehensive of the three, covering advanced IPC/IRC topics and supervisory knowledge.
- Submit your application and pay the application fee (currently $140).
- Pass the exam: a longer, harder version — 120 multiple-choice questions, a 270-minute limit, and a 75% (84 of 120) passing score.
A Master Plumber license allows you to perform all plumbing work, supervise and train apprentices, and — critically — is generally required to register as a plumbing contractor if you plan to own a business.
Registering as a Plumbing Contractor (Business Registration)
To operate your own plumbing business in Colorado, you must register as a Plumbing Contractor with the State Plumbing Board. This requires:
- Holding or employing a licensed Master Plumber to serve as the company's responsible individual (the Master Plumber and the business owner, if different people, both sign an Acknowledgment of Responsibility form; a given Master Plumber can be the responsible party for only one company at a time).
- Proof of compliance with Colorado's Workers' Compensation and Unemployment Compensation insurance laws.
Colorado Plumbing License Fees
| Item | Fee |
|---|---|
| Apprentice registration | $30 |
| Residential Plumber — application/renewal | $100 |
| Journeyworker Plumber — application/renewal | $120 |
| Master Plumber — application/renewal | $140 |
| Individual license reactivation (Residential) | $79 |
| Individual license reactivation (Journeyworker) | $91 |
| Individual license reactivation (Master) | $103 |
| Plumbing Contractor reinstatement | $227 |
Fees are set administratively by the Division under section 24-34-105, C.R.S., and are subject to change — confirm the current amount before submitting payment or an application.
License by Endorsement (Reciprocity)
Colorado offers licensure by endorsement for out-of-state plumbers. To qualify, your existing license must:
- Be active and issued and regulated by a state licensing board — not a city, county, or local municipality.
- Have been earned by testing on the current or previous version of the International Plumbing Code (IPC).
The issuing state's board must complete a verification-of-licensure form documenting your credentials and experience as substantially equivalent to Colorado's requirements.
Renewing Your Colorado Plumbing License
All Colorado plumbing licenses, Plumbing Contractor registrations, and Water Conditioning Installer/Principal/Contractor registrations run on a fixed two-year cycle, expiring on the last day of February of odd-numbered years, with renewal opening approximately four to five weeks before the deadline. New applicants issued a license within 120 days of the upcoming expiration date are "bumped" to the following cycle's deadline instead — which is why the Board's own guidance describes licenses as expiring "every three years": a license issued just after a renewal deadline can run for close to three years before its first renewal, even though the underlying cycle is fixed at two years.
Continuing Education
Residential, Journeyworker, and Master Plumbers with an active license must complete 16 hours of continuing education every two-year licensing cycle (8 hours each year, running March 1 through February 28). At least 4 of those hours must relate to plumbing codes, and no more than 2 hours may come from safety training. Plumbers who received their initial license through the examination method are not required to complete CE until after their first renewal. If you hold multiple license tiers, completing CE for your most advanced license satisfies the requirement for all lesser licenses.
Denver's Additional Municipal Requirements
Denver — Colorado's largest jurisdiction — layers its own municipal contractor-licensing system on top of the mandatory state plumbing license. Before pulling permits or operating a plumbing business within Denver city limits, you generally also need:
- A Supervisor Certificate or Journeyman Certificate from Denver Community Planning and Development (an individual competency credential), and
- A Plumbing A License (Denver's business/contractor license) to operate as a plumbing business within the city.
Denver does not accept or reciprocate contractor licenses or certificates from other counties or states for its own municipal system — a Colorado state plumbing license from DORA may substitute for Denver's supervisor certificate requirement, but confirm current applicability directly with Denver Community Planning and Development. Other Colorado cities and counties may or may not layer similar local requirements; always check with the specific jurisdiction where you plan to work.