Plumbing License in Colorado: Requirements & How to Get One

A Colorado plumbing license comes from the state, not your city. The Colorado State Plumbing Board licenses three levels of individual plumbers (Residential, Journeyworker, and Master), registers apprentices, and registers plumbing contractors. You need documented hours, a PSI exam, and an application with the Division of Professions and Occupations.

Who licenses plumbers in Colorado

The Colorado State Plumbing Board sits inside the Division of Professions and Occupations (DPO), part of the Department of Regulatory Agencies (DORA). The governing law is C.R.S. Title 12, Article 155. The Board’s rules are 3 CCR 720-1. PSI runs the exams.

Colorado law says you can’t work as a residential, journeyworker, or master plumber until the state licenses you. Working without an active license or registration is a class 2 misdemeanor.

Some cities run their own contractor licensing too. Denver is one. Its contractor licensing page says you need a supervisor certificate or a state electrical or plumbing license (or must employ a certificate holder) before you apply. Check with your local building department before you bid.

Requirements change, so confirm with the Board before you apply. This page is a plain-English guide, not legal advice.

License types

• Plumbing Apprentice. A registration, not a license. Anyone working in the trade without a Colorado license has to be registered.
• Residential Plumber. The first license level. If you hold one and work on a commercial job, Board rule says you must also stay registered as an apprentice and be supervised.
• Journeyworker Plumber. This is the old “journeyman” license. A 2024 law (HB24-1344) changed the name, effective July 1, 2025.
• Master Plumber. The top individual license. A plumbing contractor must be, or employ full time, a master plumber.
• Plumbing Contractor. A business registration. The Board also registers water conditioning contractors, installers, and principals, but those aren’t plumbing licenses.

How to become a plumber in Colorado

• Get hired and registered. Your employer registers you as an apprentice within 30 days of hire. The employer has to tell the Board within 30 days after you leave. Carry your apprentice card on the job.
• Work under supervision. One licensed plumber can supervise no more than three apprentices on the same job site. “Direct supervision” means the plumber is at the permit address or no more than five minutes away on the same site.
• Log your hours. Board rule sets the hours: 3,400 for Residential, 6,800 for Journeyworker, and 8,500 for Master. The Board counts one month of full-time work as 163 hours.
• Get the hours signed. You can’t verify your own experience. A master plumber or signing authority for your employer signs the Board’s experience form. It breaks hours out by commercial, residential, and industrial work.
• Pass the exam, then apply. Details below.

School and military credit. A trade school, community college, or high school vo-tech program of at least two years can replace field hours one for one, up to one year (2,000 hours). Military plumbing training counts one month for every six months, also capped at one year.

The six-year rule. Under C.R.S. 12-155-124, an apprentice registered for six years or more has to sit for the license exam at least every two years until passing. The Board can suspend an apprentice’s registration for not testing.

Coming January 1, 2027. HB25-1284 says a contractor can’t register an apprentice from a federally or state registered construction apprenticeship program unless that program trains for a plumbing or mechanical-related occupation. Apprentices trained directly by their contractor aren’t covered by this part.

Exams

Here’s what the current PSI candidate bulletin says:

• Residential and Journeyworker. 100 scored questions, 240 minutes. You need 70 correct (70%).
• Master. 120 scored questions, 270 minutes. You need 84 correct.
• Extra items. Each exam adds up to 10 unscored questions and 30 more minutes.
• Code books. The IPC and IRC are provided at the test center. You can’t bring or mark up your own.
• Code edition. Starting November 1, 2026, exams use the 2024 IPC and IRC. The 2021 version is available on request until February 1, 2027. Colorado’s current plumbing rules adopt the 2024 IPC, IRC, and IFGC.
• Retakes. Not the same day you tested. You can rebook as soon as the next day.
• Results. Pass or fail only. Exams can’t be reviewed.

The Master passing score needs a heads up. PSI’s bulletin calls 84 out of 120 a 70% score. The Board’s applications page and its licensing guide say 75%. Either way, the number to hit is 84.

Renewal

All plumbing licenses and contractor registrations expire on the last day of February in odd-numbered years. The current cycle ends February 28, 2027. Renewal opens about four to five weeks before that.

• Three-year cycle. Starting with the cycle that begins March 1, 2027, Colorado issues and renews plumbing licenses for three years. The Board says the next expiration after that is 2030.
• Grace period. 60 days after expiration, with a delinquency fee. After that you file for reinstatement.
• Expired over two years. You prove competency again, for example by passing the state exam before you apply for reinstatement.
• CE. 8 hours each licensure year (March 1 to February 28). At least 4 hours in every 24 months must be code related, and no more than 2 hours can be safety. You also attest that you’ve read the current Colorado Plumbing Code.
• CE providers. Use a provider on the Board’s attesting provider list. Keep your certificates for six years. See the Board’s CE page.
• New licensees. If you were first licensed by exam during the current period, you owe no CE until after your first renewal.

Cost

These come from DPO’s May 2025 Plumbing Licensing Guide and the PSI bulletin. The Board says the current fee shows on each application, so check it before you pay.

The Board’s pages don’t publish a plumbing contractor registration fee. It appears in the online application, so confirm it there. PSI exam fees aren’t refundable.

Reciprocity

Colorado has no named reciprocity partner states. It offers license by endorsement instead. Per Board rule and the applications page, you need:

• A completed state or federally approved apprenticeship, or the years and type of experience Colorado requires for that license.
• A passed state plumbing exam based on the current or previous code edition the Board adopted.
• An active license issued by another state, not a city or county, held at least six months.
• A verification of licensure form from that state’s board, plus experience affidavits from employers.

See our plumbing license reciprocity guide for how other states compare.

How to apply

• Pass the exam first. Board Rule 1.4(A)(1) says to pass the exam before you submit your application, and PSI says to apply after you pass. Some Board pages describe applying first, so call before you pay.
• Apply online. Use DPO Online Services. Upload your passing results and experience affidavits.
• Contractors. Register online and show you comply with Colorado workers’ comp and unemployment laws. The master plumber and owner sign an Acknowledgment of Responsibility. A master can be responsible for only one contractor and must tell the Board within 15 days of leaving. The contractor gets 20 days to hire a new master.
• Display your numbers. Since July 1, 2025, contractors must show their registration number and their master’s license number on vehicles (two spots, letters at least two inches tall), bids, billing, and the website homepage. Update them within 90 days of a change.
• Questions. Call DPO at 303-894-7800 or email dora_dpo_licensing@state.co.us.

Incomplete applications expire one year after the Board gets them.

FAQ

How long does it take to get a Colorado plumbing license?

At 163 hours a month, 3,400 hours is about two years of full-time work for Residential. Journeyworker takes about four years and Master about five.

Is a journeyworker the same as a journeyman?

Yes. Colorado renamed the journeyman license to Journeyworker Plumber on July 1, 2025.

Do I need a master plumber to start a plumbing company?

Yes. A plumbing contractor must be, or employ full time, a master plumber who supervises all the company’s plumbing work.

Can I use my out-of-state license in Colorado?

Not directly. You apply by endorsement. Your license must be state issued, active, held six months, and earned on a comparable exam.

Next steps

Start by finding a registered plumbing contractor to hire you and register you as an apprentice. To compare Colorado with other states, see our plumbing license by state page, the full plumbing license guide, plumbing license cost by state, and plumbing license renewal by state. Working near the border? Check the New Mexico plumbing license and Wyoming plumbing license pages too. When you’re ready to run your own shop, read how to start a plumbing business.