Plumber License in Colorado — Requirements, Fees & Exam

How to get licensed as a plumber in Colorado: PSI exam, 8 hrs CE — verified from Colorado State Plumbing Board.

Source-verified

Requirements below are drawn from Colorado State Plumbing Board (official site) and last verified October 9, 2026. Boards change fees and rules often — confirm before acting.

At a glance

Registered Plumbing Apprentice (AP)

Experience: Entry-level credential. The Plumbing Licensing Guide lists basic eligibility: be at least 18 years of age, possess a high school diploma or GED equivalent, have a valid driver's license, and have a Social Security Card… details below
Exam: None for initial registration. Under C.R.S. 12-155-124(4) (contingent on available department resources or gifts, grants and donations), an apprentice registered for at least six years must take the license examination… details below
Fee: $30 registration fee ("currently $30", Plumbing Licensing Guide)… full text
$30 registration fee ("currently $30", Plumbing Licensing Guide); the fee requirement is C.R.S. 12-155-108(2)(c): "No apprentice shall be registered until payment of a registration or registration renewal fee, as determined by the board, has been made." DPO: "There is no fee for notifying the Board that an apprentice has been terminated."

Residential Plumber (RP)

Experience: Two years (3,400 hours) of practical experience: DPO Applications page "You must verify 2 years (3,400 hours) of practical experience"; Rule 1.4(A)(3)(f)(1) "Residential Plumber 3,400"… full text
Two years (3,400 hours) of practical experience: DPO Applications page "You must verify 2 years (3,400 hours) of practical experience"; Rule 1.4(A)(3)(f)(1) "Residential Plumber 3,400"; C.R.S. 12-155-110(1)(a) caps the experience the board may require at 3,400 hours. A graduate of a board-approved community college or trade school plumbing program "receives one year of work experience credit" (12-155-110(1)(b)(I)); other academic training, including military training, is credited by a uniform ratio set by rule (12-155-110(1)(b)(II)): Rule 1.4(A)(3)(d) one hour of classroom training equals one hour of on-the-job training up to one year (2,000 hours), and Rule 1.4(A)(3)(e) one month for every six months of military training or experience up to one year. Experience is documented on Affidavit of Experience forms; Rule 1.4(A)(3)(g): "Applicants cannot verify their own experience." SCOPE: C.R.S. 12-155-103(13) defines a residential plumber as one qualified "to install plumbing and equipment in one-, two-, three-, and four-family dwellings, which dwellings must not extend more than two stories aboveground." Rule 1.4(H): "Residential Plumbers must maintain an apprentice registration when working on commercial jobs and be supervised accordingly."
Exam: Residential Plumber Examination through PSI Services LLC: "The exam consists of 100 multiple-choice questions with a 240-minute time limit… full text
Residential Plumber Examination through PSI Services LLC: "The exam consists of 100 multiple-choice questions with a 240-minute time limit. A score of 70% (70 correct items) is required to pass" (Plumbing Licensing Guide). The Guide says to study the IPC and IRC as adopted by Colorado ("currently the 2018 editions are referenced for exams"). The PSI candidate handbook gives the exam fee (DPO Applications page); no DPO page or rule states the amount. DPO: "Examinations are administered in English only through a private testing agency." The Guide says the exam "is typically open-book." Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says "Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education," and DPO's online application previews say "You must have taken and passed the Residential Plumber examination administered by PSI Exams before submitting this application." DPO's Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: "Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided"). The rule is the binding text; the board's own pages disagree with it.
Fee: $100 application fee and $100 renewal fee (Plumbing Licensing Guide: "currently $100"; renewal "Residential: $100"). Fees are set under C.R.S. 12-155-110(1)(c) and 12-20-105.

Journeyworker Plumber (JP)

Experience: Four years (6,800 hours) of practical experience: Rule 1.4(A)(3)(f)(2) "Journeyworker Plumber 6,800"… full text
Four years (6,800 hours) of practical experience: Rule 1.4(A)(3)(f)(2) "Journeyworker Plumber 6,800"; DPO: "The maximum experience the board requires for an applicant to qualify to receive a Journeyworker Plumber's license is 4 years (6,800 hours) of practical experience." The Guide says this "can include your residential plumbing experience." Education and military credit as for the Residential Plumber (12-155-110(1)(b); Rule 1.4(A)(3)(d)-(e)). The Affidavit of Experience is signed by "the master plumber for, or a signatory authority of, the plumbing contractor, or employer" (Rule 1.4(A)(3)(c)); "Applicants cannot verify their own experience" (Rule 1.4(A)(3)(g)). The title changed from 'journeyman' to 'journeyworker' under HB24-1344, effective July 1, 2025.
Exam: Journeyworker Plumber Examination through PSI Services LLC: "The exam consists of 100 multiple-choice questions with a 240-minute time limit… full text
Journeyworker Plumber Examination through PSI Services LLC: "The exam consists of 100 multiple-choice questions with a 240-minute time limit. A score of 70% (70 correct items) is required to pass" (Plumbing Licensing Guide). The Guide lists topics including water supply, vents, fixtures, piping support, traps, storm drainage, sanitary drainage, indirect/special waste, and isometric analysis, studied from the IPC and IRC as adopted by Colorado. The PSI candidate handbook gives the exam fee (DPO Applications page); no DPO page or rule states the amount. DPO: "Examinations are administered in English only through a private testing agency." The Guide says the exam "is typically open-book." Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says "Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education," and DPO's online application previews say "You must have taken and passed the Journeyworker Plumber examination administered by PSI Exams before submitting this application." DPO's Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: "Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided"). The rule is the binding text; the board's own pages disagree with it.
Fee: $120 application fee and $120 renewal fee (Plumbing Licensing Guide: "currently $120"; renewal "Journeyworker: $120"). Fees are set under C.R.S. 12-155-110(1)(c) and 12-20-105.

Master Plumber (MP)

Experience: Five full-time years (8,500 hours) of practical experience: DPO "An applicant for a master plumber's license must furnish evidence of having obtained five full-time years (8,500 hours) of practical experience"… full text
Five full-time years (8,500 hours) of practical experience: DPO "An applicant for a master plumber's license must furnish evidence of having obtained five full-time years (8,500 hours) of practical experience"; Rule 1.4(A)(3)(f)(3) "Master Plumber 8,500". The Guide: "This includes all prior experience." The Affidavit of Experience is signed by "the master plumber for, or a signatory authority of, the plumbing contractor, or employer" (Rule 1.4(A)(3)(c)); "Applicants cannot verify their own experience" (Rule 1.4(A)(3)(g)). DPO's Licensing Guide says a Master Plumber license allows the holder to perform all plumbing work, including supervising and training apprentices, and that it is, as a general rule, required to register as a plumbing contractor for someone who plans to own a business. A plumbing contractor must either be, or employ full-time, a master plumber (C.R.S. 12-155-108(3)).
Exam: Master Plumber Examination through PSI Services LLC: "The exam consists of 120 multiple-choice questions with a 270-minute time limit… full text
Master Plumber Examination through PSI Services LLC: "The exam consists of 120 multiple-choice questions with a 270-minute time limit. A higher score of 75% (84 correct items) is required to pass" (Plumbing Licensing Guide). The Guide: the exam "is the most comprehensive, covering all aspects of the IPC and IRC, including advanced topics and supervisory knowledge." The PSI candidate handbook gives the exam fee (DPO Applications page); no DPO page or rule states the amount. DPO: "Examinations are administered in English only through a private testing agency." The Guide says the exam "is typically open-book." Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says "Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education," and DPO's online application previews say "You must have taken and passed the Master Plumber examination administered by PSI Exams before submitting this application." DPO's Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: "Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided"). The rule is the binding text; the board's own pages disagree with it.
Fee: $140 application fee and $140 renewal fee (Plumbing Licensing Guide: "currently $140"; renewal "Master: $140"). Fees are set under C.R.S. 12-155-110(1)(c) and 12-20-105.

Plumbing Contractor (PC) (Business Registration)

Experience: Registration required to operate as a plumbing contractor: C.R.S. 12-155-108(3) "A person shall not operate as a plumbing contractor until the contractor has obtained registration from the board," on payment of the fee… full text
Registration required to operate as a plumbing contractor: C.R.S. 12-155-108(3) "A person shall not operate as a plumbing contractor until the contractor has obtained registration from the board," on payment of the fee and evidence of compliance with workers' compensation and unemployment compensation laws. The contractor "must either be, or employ full-time, a master plumber, who shall be in charge of the supervision of all plumbing work performed by the contractor. A master plumber shall not be responsible for more than one plumbing contractor at a time." The Guide: "The master plumber and company owner (if separate individuals) must sign an Acknowledgment of Responsibility Form." Insurance amounts come from the Guide only (not the statute or rules): "Property Damage Insurance (minimum $100,000) General Liability Coverage (minimum $300,000) Workers' Compensation Insurance (if you have employees)". If the contractor loses its master plumber it has "twenty days in which to hire another master plumber" before being placed in "Need Master Hire-Cannot Practice" status (Rule 1.4(I)); a temporary master permit may be issued to finish a current project if the contractor has a journeyworker plumber full-time (12-155-117(4)).
Exam: None for the business entity registration. The qualifying Master Plumber of record must hold an active Master Plumber license gained by passing the Colorado Master Plumber examination or approved endorsement.
Fee: Registration fee set by the board under C.R.S. 12-155-105 (12-155-108(3)). The amount is not stated in DPO's Plumbing Licensing Guide (May 2025) or in the State Plumbing Board rules (3 CCR 720-1).

Show the other 1 credential type

Water Conditioning Registrations (Contractor, Installer, Principal)

Experience: Specialized registrations authorized under C.R.S. 12-155-108(4), (5), and (6) for individuals and contractors whose work is restricted to the installation, servicing, and repair of water conditioning appliances… details below
Exam: No board examination is described. Installers and principals register on proof of certification "by a national water conditioning association recognized by the board" (C.R.S. 12-155-108(5), (6)(a))… details below
Fee: Registration fees are set by the board ("upon payment of the fee as provided in section 12-155-105", C.R.S. 12-155-108(4)-(6)); amounts not published on DPO's plumbing pages.

Issuing agency: Colorado State Plumbing Board Official site
How to apply: Official application page
Renewal: Currently biennial: DPO "All Plumbing Licenses, Water Conditioning Installer/Principal Registrations, Plumbing Contractor Registrations and Water Conditioning Contractor Registrations expire on the final day of February… full text
Currently biennial: DPO "All Plumbing Licenses, Water Conditioning Installer/Principal Registrations, Plumbing Contractor Registrations and Water Conditioning Contractor Registrations expire on the final day of February of odd-numbered years and must be renewed to continue practicing." Renewal window: DPO's Applications page says "renewals open approximately 4-5 weeks prior to the expiration date"; the Guide says "You can typically renew up to six weeks before the expiration date." TRANSITION: C.R.S. 12-155-112(1)(a) (HB24-1344): "Beginning with the plumbing license cycle that begins on March 1, 2027, and each subsequent license cycle thereafter, the board shall issue and renew plumbing licenses for a period of three years unless otherwise determined by the director." Grace period: "A licensee or registrant shall have a sixty-day grace period after the expiration of the license or registration to renew" with a delinquency fee (Rule 1.4(E)(1)(a)). Reinstatement more than sixty days but less than two years after expiration: reinstatement application, reinstatement fee, and evidence of the continuing education required by Rule 1.4(E)(3) (Rule 1.4(E)(2)(a); 12-155-112(2)(c)). Expired two or more years: C.R.S. 12-155-112(2)(b) requires the person to demonstrate competency by "(I) Providing verification of a license in good standing from another state and proof of active practice in that state for the year previous to the date of receipt of the reinstatement application; (II) Satisfactorily passing the state plumbing examination in accordance with section 12-155-110; or (III) Any other means approved by the board." Rule 1.4(E)(2)(b) lists four routes: passing the State plumbing examination; verification of an active, substantially equivalent license in another state plus proof of active practice for the year before the application; "Holding an active Colorado plumbing license that is more advanced that the license to be reinstated"; or other means approved by the Board. The Guide states only the exam route ("Take and pass the full licensing examination BEFORE applying for reinstatement").
Continuing education: 8 hours of continuing education per licensure year. DPO: "All Residential, Journeyworker, and Master Plumbers with an Active Colorado license must complete at least 8 hours of Continuing Education (CE) during EACH YEAR… full text
8 hours of continuing education per licensure year. DPO: "All Residential, Journeyworker, and Master Plumbers with an Active Colorado license must complete at least 8 hours of Continuing Education (CE) during EACH YEAR (March 1 through February 28) of the two-year license period"; the Guide says "16 hours of continuing education every two-year licensing cycle (8 hours each year)." Statute: C.R.S. 12-155-112(3)(a) ("eight hours of continuing education for every twelve months" since the later of the last renewal or reinstatement; not applicable to the first renewal after licensure by examination). Rule 1.4(E)(3)(d)(1): hours are chosen from the listed core competencies, "except that, within every twenty-four month period, a minimum of four (4)" "continuing education hours must be related to codes as defined in Board Rule 1.2 and a maximum of two (2) hours can be related to safety training." Code attestation: "Licensees must attest upon renewal that they have read the current Colorado Plumbing Code" (DPO; Rule 1.4(E)(3)(d)(2)). First renewal: "Plumbers who received their initial license through the examination method during the current license period are not required to complete CE until after the first renewal of their license" (DPO). Multiple licenses: CE for the most advanced license satisfies all lesser licenses (Rule 1.4(E)(3)(h)). Providers: DPO "ALL CE COURSES must be taken through a CE vendor or provider that has attested to the Board that their courses and instructors meet the continuing education requirements of Board Rule." Records: "Licensees must maintain their own CE records for at least six years" (DPO; Rule 1.4(E)(3)(f)(2)); documentation is submitted only if requested (audit). Water conditioning installers and principals are not subject to the CE rule (Rule 1.4(E)(3)(d)(4)). From March 1, 2027, the license period lengthens: C.R.S. 12-155-112(1)(a) says that "Beginning with the plumbing license cycle that begins on March 1, 2027, and each subsequent license cycle thereafter, the board shall issue and renew plumbing licenses for a period of three years unless otherwise determined by the director." The statutory rate in 12-155-112(3)(a) is "eight hours of continuing education for every twelve months".

Every requirement in the agency's own words: Requirements in detail, below.

Legal basis

Colorado State Plumbing Board administers plumber licensing in Colorado. Every figure below is verified against the board’s own official pages and dated. Who must personally hold a credential — the contractor, the business, or the individual worker — is set out under Requirements.

What it’s called

Colorado licenses individual tradespeople through the Colorado State Plumbing Board (DORA Division of Professions and Occupations). Key credential designations include: (1) ‘Journeyworker Plumber’ – the term replaced ‘Journeyman Plumber’ in the practice act under HB24-1344, effective July 1, 2025; both refer to the same license tier (code ‘JP’). (2) ‘Residential Plumber’ (code ‘RP’) – limited to one- to four-family dwellings not more than two stories above ground (C.R.S. 12-155-103(13)). (3) ‘Master Plumber’ (code ‘MP’) – the highest individual credential; the Guide says it “allows you to perform all plumbing work”; a plumbing contractor must be or employ one. (4) ‘Plumbing Apprentice’ (code ‘AP’) – mandatory registration for unlicensed individuals employed in the trade. (5) ‘Plumbing Contractor’ (code ‘PC’) – the business registration. (6) ‘Water Conditioning Installer / Principal / Contractor’ (codes ‘WI’, ‘WP’, ‘WC’) – registrations for water conditioning appliance work.

License types & fees

Type	Experience	Exam	Fee
Registered Plumbing Apprentice (AP)	Entry-level credential. The Plumbing Licensing Guide lists basic eligibility: be at least 18 years of age, possess a high school diploma or GED equivalent, have a valid driver's license, and have a Social Security Card. Under C.R.S. 12-155-108(2)(a), apprentices "shall, within thirty days after the date of initial employment, be registered with the board"; the employer is responsible for the registration (12-155-108(2)(b)). DPO: "Any individual employed in the plumbing trade is considered an apprentice and must be registered until such time as the individual has obtained a Colorado Plumber's license." The apprentice works under the supervision of a licensed plumber at the job site, and "One licensed journeyworker plumber, master plumber, or residential plumber shall not supervise more than three plumbing apprentices at the same job site" (C.R.S. 12-155-124(1)). By July 1 each year, registered plumbing contractors and registered apprenticeship programs report each apprentice's cumulative practical training hours to the board (12-155-124(3)). Long-term apprentices must test: see the exam field and the 'Mandatory testing for long-term registered apprentices' requirement.	None for initial registration. Under C.R.S. 12-155-124(4) (contingent on available department resources or gifts, grants and donations), an apprentice registered for at least six years must take the license examination at least every two years in alignment with the license renewal cycle until passing: (4)(a)(I) covers apprentices who have completed 6,800 hours of practical training and meet all other license requirements; (4)(b) covers apprentices registered six years or more who do NOT meet the license requirements, who must still test every two years and, after passing, meet all other requirements before a license issues.	$30 registration fee ("currently $30", Plumbing Licensing Guide); the fee requirement is C.R.S. 12-155-108(2)(c): "No apprentice shall be registered until payment of a registration or registration renewal fee, as determined by the board, has been made." DPO: "There is no fee for notifying the Board that an apprentice has been terminated."
Residential Plumber (RP)	Two years (3,400 hours) of practical experience: DPO Applications page "You must verify 2 years (3,400 hours) of practical experience"; Rule 1.4(A)(3)(f)(1) "Residential Plumber 3,400"; C.R.S. 12-155-110(1)(a) caps the experience the board may require at 3,400 hours. A graduate of a board-approved community college or trade school plumbing program "receives one year of work experience credit" (12-155-110(1)(b)(I)); other academic training, including military training, is credited by a uniform ratio set by rule (12-155-110(1)(b)(II)): Rule 1.4(A)(3)(d) one hour of classroom training equals one hour of on-the-job training up to one year (2,000 hours), and Rule 1.4(A)(3)(e) one month for every six months of military training or experience up to one year. Experience is documented on Affidavit of Experience forms; Rule 1.4(A)(3)(g): "Applicants cannot verify their own experience." SCOPE: C.R.S. 12-155-103(13) defines a residential plumber as one qualified "to install plumbing and equipment in one-, two-, three-, and four-family dwellings, which dwellings must not extend more than two stories aboveground." Rule 1.4(H): "Residential Plumbers must maintain an apprentice registration when working on commercial jobs and be supervised accordingly."	Residential Plumber Examination through PSI Services LLC: "The exam consists of 100 multiple-choice questions with a 240-minute time limit. A score of 70% (70 correct items) is required to pass" (Plumbing Licensing Guide). The Guide says to study the IPC and IRC as adopted by Colorado ("currently the 2018 editions are referenced for exams"). The PSI candidate handbook gives the exam fee (DPO Applications page); no DPO page or rule states the amount. DPO: "Examinations are administered in English only through a private testing agency." The Guide says the exam "is typically open-book." Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says "Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education," and DPO's online application previews say "You must have taken and passed the Residential Plumber examination administered by PSI Exams before submitting this application." DPO's Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: "Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided"). The rule is the binding text; the board's own pages disagree with it.	$100 application fee and $100 renewal fee (Plumbing Licensing Guide: "currently $100"; renewal "Residential: $100"). Fees are set under C.R.S. 12-155-110(1)(c) and 12-20-105.
Journeyworker Plumber (JP)	Four years (6,800 hours) of practical experience: Rule 1.4(A)(3)(f)(2) "Journeyworker Plumber 6,800"; DPO: "The maximum experience the board requires for an applicant to qualify to receive a Journeyworker Plumber's license is 4 years (6,800 hours) of practical experience." The Guide says this "can include your residential plumbing experience." Education and military credit as for the Residential Plumber (12-155-110(1)(b); Rule 1.4(A)(3)(d)-(e)). The Affidavit of Experience is signed by "the master plumber for, or a signatory authority of, the plumbing contractor, or employer" (Rule 1.4(A)(3)(c)); "Applicants cannot verify their own experience" (Rule 1.4(A)(3)(g)). The title changed from 'journeyman' to 'journeyworker' under HB24-1344, effective July 1, 2025.	Journeyworker Plumber Examination through PSI Services LLC: "The exam consists of 100 multiple-choice questions with a 240-minute time limit. A score of 70% (70 correct items) is required to pass" (Plumbing Licensing Guide). The Guide lists topics including water supply, vents, fixtures, piping support, traps, storm drainage, sanitary drainage, indirect/special waste, and isometric analysis, studied from the IPC and IRC as adopted by Colorado. The PSI candidate handbook gives the exam fee (DPO Applications page); no DPO page or rule states the amount. DPO: "Examinations are administered in English only through a private testing agency." The Guide says the exam "is typically open-book." Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says "Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education," and DPO's online application previews say "You must have taken and passed the Journeyworker Plumber examination administered by PSI Exams before submitting this application." DPO's Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: "Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided"). The rule is the binding text; the board's own pages disagree with it.	$120 application fee and $120 renewal fee (Plumbing Licensing Guide: "currently $120"; renewal "Journeyworker: $120"). Fees are set under C.R.S. 12-155-110(1)(c) and 12-20-105.
Master Plumber (MP)	Five full-time years (8,500 hours) of practical experience: DPO "An applicant for a master plumber's license must furnish evidence of having obtained five full-time years (8,500 hours) of practical experience"; Rule 1.4(A)(3)(f)(3) "Master Plumber 8,500". The Guide: "This includes all prior experience." The Affidavit of Experience is signed by "the master plumber for, or a signatory authority of, the plumbing contractor, or employer" (Rule 1.4(A)(3)(c)); "Applicants cannot verify their own experience" (Rule 1.4(A)(3)(g)). DPO's Licensing Guide says a Master Plumber license allows the holder to perform all plumbing work, including supervising and training apprentices, and that it is, as a general rule, required to register as a plumbing contractor for someone who plans to own a business. A plumbing contractor must either be, or employ full-time, a master plumber (C.R.S. 12-155-108(3)).	Master Plumber Examination through PSI Services LLC: "The exam consists of 120 multiple-choice questions with a 270-minute time limit. A higher score of 75% (84 correct items) is required to pass" (Plumbing Licensing Guide). The Guide: the exam "is the most comprehensive, covering all aspects of the IPC and IRC, including advanced topics and supervisory knowledge." The PSI candidate handbook gives the exam fee (DPO Applications page); no DPO page or rule states the amount. DPO: "Examinations are administered in English only through a private testing agency." The Guide says the exam "is typically open-book." Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says "Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education," and DPO's online application previews say "You must have taken and passed the Master Plumber examination administered by PSI Exams before submitting this application." DPO's Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: "Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided"). The rule is the binding text; the board's own pages disagree with it.	$140 application fee and $140 renewal fee (Plumbing Licensing Guide: "currently $140"; renewal "Master: $140"). Fees are set under C.R.S. 12-155-110(1)(c) and 12-20-105.
Plumbing Contractor (PC) (Business Registration)	Registration required to operate as a plumbing contractor: C.R.S. 12-155-108(3) "A person shall not operate as a plumbing contractor until the contractor has obtained registration from the board," on payment of the fee and evidence of compliance with workers' compensation and unemployment compensation laws. The contractor "must either be, or employ full-time, a master plumber, who shall be in charge of the supervision of all plumbing work performed by the contractor. A master plumber shall not be responsible for more than one plumbing contractor at a time." The Guide: "The master plumber and company owner (if separate individuals) must sign an Acknowledgment of Responsibility Form." Insurance amounts come from the Guide only (not the statute or rules): "Property Damage Insurance (minimum $100,000) General Liability Coverage (minimum $300,000) Workers' Compensation Insurance (if you have employees)". If the contractor loses its master plumber it has "twenty days in which to hire another master plumber" before being placed in "Need Master Hire-Cannot Practice" status (Rule 1.4(I)); a temporary master permit may be issued to finish a current project if the contractor has a journeyworker plumber full-time (12-155-117(4)).	None for the business entity registration. The qualifying Master Plumber of record must hold an active Master Plumber license gained by passing the Colorado Master Plumber examination or approved endorsement.	Registration fee set by the board under C.R.S. 12-155-105 (12-155-108(3)). The amount is not stated in DPO's Plumbing Licensing Guide (May 2025) or in the State Plumbing Board rules (3 CCR 720-1).
Water Conditioning Registrations (Contractor, Installer, Principal)	Specialized registrations authorized under C.R.S. 12-155-108(4), (5), and (6) for individuals and contractors whose work is restricted to the installation, servicing, and repair of water conditioning appliances (water softeners, conditioners, and filters). Licensed residential, journeyworker, and master plumbers are statutorily permitted to perform water conditioning work without holding these specialized registrations (C.R.S. 12-155-108(1)(b)).	No board examination is described. Installers and principals register on proof of certification "by a national water conditioning association recognized by the board" (C.R.S. 12-155-108(5), (6)(a)). Rule 1.4(A)(4)(a)(2): an installer "shall possess and maintain an active Certified Installer (CI) certification from the Water Quality Association or an equivalent certification as approved by the Plumbing Board"; Rule 1.4(A)(4)(b)(2): a principal holds an active CI plus an active Certified Water Specialist (CWS) or Master Water Specialist (MWS) certification from the Water Quality Association, or a board-approved equivalent. A water conditioning contractor must be or employ full time a water conditioning principal (Rule 1.4(A)(4)(c)).	Registration fees are set by the board ("upon payment of the fee as provided in section 12-155-105", C.R.S. 12-155-108(4)-(6)); amounts not published on DPO's plumbing pages.

Who does NOT need this license — exemptions

Colorado’s statutory plumbing exemptions are codified at C.R.S. 12-155-118:

Material Suppliers: (1) Any person selling or dealing in plumbing materials or supplies, but not engaged in the installation, alteration, repairing, or removal of plumbing, is not required to employ or have a licensed plumber in charge.
Property Owners and Routine Maintenance: (2) Nothing in Article 155 requires an individual to hold a license to perform plumbing work on the individual’s own property or residence or prevents a person from employing an individual on either a full- or part-time basis to do routine repair, maintenance, and replacement of sinks, faucets, drains, showers, tubs, toilets, and domestic appliances and equipment equipped with backflow preventers; EXCEPT THAT, if such property or residence is intended for sale or resale by a person engaged in the business of constructing or remodeling structures, or is rental property that is occupied or to be occupied by tenants for lodging (transient or permanent), or is a commercial or industrial building, the owner is responsible for and the property is subject to the provisions of Article 155 pertaining to licensing, unless specifically exempted therein.
Manufactured Housing: (3) The manufacture of housing subject to Title 24, Article 32, or the installation of individual residential or temporary construction units of manufactured housing water and sewer hookups inspected under C.R.S. 12-155-105(2).
Backflow Prevention Devices (Amended by HB25-1077, March 28, 2025): (4) Individuals who are engaged in inspecting, testing, or repairing backflow prevention devices are EXEMPT from licensure under Article 155. Individuals who engage in the installation or removal of backflow prevention devices are NOT exempt, except when installing or replacing a backflow device on a stand-alone fire suppression system pursuant to C.R.S. 24-33.5-1202(6).
Federal Employees: (5) Employees of the federal government performing plumbing work on federal property.
Appliances, Mechanical Systems, and Municipal Infrastructure: (6)(a) No plumbing license, registration, or permit is required for: (I) Installation, extension, alteration, or maintenance (including related water and indirect waste piping) of domestic appliances equipped with backflow preventers, including lawn sprinkler systems; residential ice makers, humidifiers, electrostatic filter washers, or water heating appliances; building heating appliances and systems; fire protection systems except for multipurpose residential fire sprinkler systems in one- and two-family dwellings and townhouses that are part of the potable water supply; air conditioning installations; process and industrial equipment and piping systems; or indirect drainage systems not a part of a sanitary sewer system; or (II) Repair and replacement of garbage disposals and dishwashers directly connected to sanitary sewers, including necessary tail pipes and traps; or routine repair, maintenance, and replacement of sinks, faucets, drains, showers, tubs, and toilets. (6)(b) Notwithstanding (6)(a), ‘plumbing’ does not include: (I) installations, extensions, improvements, remodeling, additions, and alterations in water and sewer systems owned or acquired by counties (Title 30, Article 20), cities and towns (Title 31, Article 35), or water and sanitation districts (Title 32, Article 1 or 4); (II) installations, extensions, improvements, remodeling, additions, and alterations performed by contractors employed by counties, cities, towns, or water and sewer districts that connect to the plumbing system within a property line; or (III) performance, location, construction, alteration, installation, and use of on-site wastewater treatment systems under Title 25, Article 10 that are located within a property line.

Fees

Amounts from DPO’s Plumbing Licensing Guide (May 2025), the only DPO source that states them (DPO publishes no plumbing fee page; the rules say fees are established under C.R.S. 12-20-105): Registered Plumbing Apprentice (AP): $30 registration fee (“currently $30”); no fee for notifying the Board that an apprentice has been terminated (DPO). Residential Plumber (RP): $100 application fee; $100 renewal fee. Journeyworker Plumber (JP): $120 application fee; $120 renewal fee. Master Plumber (MP): $140 application fee; $140 renewal fee. Plumbing Contractor (PC) and water conditioning registrations: fee set by the board under 12-155-105; the amount is not stated in DPO’s Plumbing Licensing Guide (May 2025) or in the State Plumbing Board rules. Examination fee: stated in the PSI candidate handbook (DPO); not published by DPO. Late renewal: Rule 1.4(E)(1)(a) allows a sixty-day grace period after expiration in which a delinquency fee is charged; after that, reinstatement requires a reinstatement application and “the current reinstatement fee” (Rule 1.4(E)(2)).

Exam

Colorado plumbing examinations are administered through PSI Services LLC (Plumbing Licensing Guide; DPO application previews). DPO Applications page: “Questions are based on the currently adopted codes, namely, the International Plumbing Code (IPC), the International Fuel Gas Code (IFGC), and the Rules and Regulations as adopted by the Examining Board of Plumbers”; the Guide tells Residential candidates to study the IPC and IRC (“currently the 2018 editions are referenced for exams”). Format and pass marks (Guide): Residential Plumber 100 multiple-choice questions, 240 minutes, 70% (70 correct items); Journeyworker Plumber 100 questions, 240 minutes, 70% (70 correct items); Master Plumber 120 questions, 270 minutes, 75% (84 correct items). DPO: “An overall score of 70% is required to pass the written portion of the examination for Residential and Journeyworker examinees, 75% is required for the Master examinee. Your results will indicate either pass or fail.” The Guide says the exam “is typically open-book, allowing you to reference approved code books.” Language: DPO says “Examinations are administered in English only through a private testing agency.” Fee: set out in the PSI candidate handbook (DPO); no DPO page or rule states the amount. Sequence: 3 CCR 720-1 Rule 1.4(A)(1) (rules effective 08/14/2026) says “Candidates must pass the required examination(s) before submitting an application to the Board with the required experience and education,” and DPO’s online application previews say “You must have taken and passed the Master Plumber examination administered by PSI Exams before submitting this application.” DPO’s Applications page and its May 2025 Plumbing Licensing Guide still describe approval first (Applications page: “Once your application has been approved by this office, a letter of acceptance and information on how to contact PSI to obtain a candidate handbook will be provided”). The rule is the binding text; the board’s own pages disagree with it. (Master Plumber preview; the Residential and Journeyworker previews say the same of their exams.)

Renewal & continuing education

Currently biennial: DPO “All Plumbing Licenses, Water Conditioning Installer/Principal Registrations, Plumbing Contractor Registrations and Water Conditioning Contractor Registrations expire on the final day of February of odd-numbered years and must be renewed to continue practicing.” Renewal window: DPO’s Applications page says “renewals open approximately 4-5 weeks prior to the expiration date”; the Guide says “You can typically renew up to six weeks before the expiration date.” TRANSITION: C.R.S. 12-155-112(1)(a) (HB24-1344): “Beginning with the plumbing license cycle that begins on March 1, 2027, and each subsequent license cycle thereafter, the board shall issue and renew plumbing licenses for a period of three years unless otherwise determined by the director.” Grace period: “A licensee or registrant shall have a sixty-day grace period after the expiration of the license or registration to renew” with a delinquency fee (Rule 1.4(E)(1)(a)). Reinstatement more than sixty days but less than two years after expiration: reinstatement application, reinstatement fee, and evidence of the continuing education required by Rule 1.4(E)(3) (Rule 1.4(E)(2)(a); 12-155-112(2)(c)). Expired two or more years: C.R.S. 12-155-112(2)(b) requires the person to demonstrate competency by “(I) Providing verification of a license in good standing from another state and proof of active practice in that state for the year previous to the date of receipt of the reinstatement application; (II) Satisfactorily passing the state plumbing examination in accordance with section 12-155-110; or (III) Any other means approved by the board.” Rule 1.4(E)(2)(b) lists four routes: passing the State plumbing examination; verification of an active, substantially equivalent license in another state plus proof of active practice for the year before the application; “Holding an active Colorado plumbing license that is more advanced that the license to be reinstated”; or other means approved by the Board. The Guide states only the exam route (“Take and pass the full licensing examination BEFORE applying for reinstatement”). 8 hours of continuing education per licensure year. DPO: “All Residential, Journeyworker, and Master Plumbers with an Active Colorado license must complete at least 8 hours of Continuing Education (CE) during EACH YEAR (March 1 through February 28) of the two-year license period”; the Guide says “16 hours of continuing education every two-year licensing cycle (8 hours each year).” Statute: C.R.S. 12-155-112(3)(a) (“eight hours of continuing education for every twelve months” since the later of the last renewal or reinstatement; not applicable to the first renewal after licensure by examination). Rule 1.4(E)(3)(d)(1): hours are chosen from the listed core competencies, “except that, within every twenty-four month period, a minimum of four (4)” “continuing education hours must be related to codes as defined in Board Rule 1.2 and a maximum of two (2) hours can be related to safety training.” Code attestation: “Licensees must attest upon renewal that they have read the current Colorado Plumbing Code” (DPO; Rule 1.4(E)(3)(d)(2)). First renewal: “Plumbers who received their initial license through the examination method during the current license period are not required to complete CE until after the first renewal of their license” (DPO). Multiple licenses: CE for the most advanced license satisfies all lesser licenses (Rule 1.4(E)(3)(h)). Providers: DPO “ALL CE COURSES must be taken through a CE vendor or provider that has attested to the Board that their courses and instructors meet the continuing education requirements of Board Rule.” Records: “Licensees must maintain their own CE records for at least six years” (DPO; Rule 1.4(E)(3)(f)(2)); documentation is submitted only if requested (audit). Water conditioning installers and principals are not subject to the CE rule (Rule 1.4(E)(3)(d)(4)). From March 1, 2027, the license period lengthens: C.R.S. 12-155-112(1)(a) says that “Beginning with the plumbing license cycle that begins on March 1, 2027, and each subsequent license cycle thereafter, the board shall issue and renew plumbing licenses for a period of three years unless otherwise determined by the director.” The statutory rate in 12-155-112(3)(a) is “eight hours of continuing education for every twelve months”.

How to apply

Applications are handled by Colorado State Plumbing Board. Start at the official application page .

Requirements in detail

Who must hold a credential (Individual vs Contractor model)
Colorado licenses the INDIVIDUAL worker at the state level through the Colorado State Plumbing Board, housed within the Department of Regulatory Agencies (DORA) Division of Professions and Occupations (DPO). C.R.S. 12-155-108(1)(a): "A person shall not engage in or work at the business, trade, or calling of a residential, journeyworker, or master plumber in this state until the person has received a license from the division, upon written notice from the board or its authorized agent, or a temporary permit from the board or its authorized agent". The Guide: "The Board licenses, registers, and regulates plumbers, apprentices, and plumbing contractors." Any individual employed in the plumbing trade who is not licensed must be registered as a Plumbing Apprentice (12-155-108(2); DPO). An employed plumber cannot rely on an employer's business registration; the individual must personally hold an active Colorado license or apprentice registration. Separately, a business operating as a plumbing contractor must register as a Plumbing Contractor under C.R.S. 12-155-108(3).
Apprentice registration and the 30-day mandate
Under C.R.S. 12-155-108(2)(a), all plumbing apprentices must be registered with the State Plumbing Board within thirty days after the date of initial employment; the employer is responsible for the registration (12-155-108(2)(b)). DPO describes a two-step process: "Apprentice Applicants must create a new account and register as an apprentice," and contractors add the apprentice to their contractor registration. DPO: "After the initial registration, a card with a registration number is given to the apprentice. This number will remain the same through any employment changes. It is the apprentice's responsibility to have the card with them while working in the trade. Failure to do so may result in disciplinary action." Employers must notify the Board within 30 days when an apprentice terminates employment (Rule 1.4(J)); "There is no fee for notifying the Board that an apprentice has been terminated." From January 1, 2027, C.R.S. 12-155-124(3.5) bars a registered plumbing contractor from registering an apprentice who is in a US DOL- or state-registered construction apprenticeship program unless that program trains for a plumbing or mechanical-related occupation (BLS OES codes 17.3013, 47.2152, or 49.9021); it does not apply to apprentices trained directly by the contractor or in a non-registered program.
Direct supervision requirements and job-site ratios
C.R.S. 12-155-124(1): a plumbing apprentice "shall not do any plumbing work for which a license is required pursuant to this article 155 except under the supervision of a licensed plumber. Supervision requires that a licensed plumber supervise apprentices at the job site. One licensed journeyworker plumber, master plumber, or residential plumber shall not supervise more than three plumbing apprentices at the same job site." The supervising plumber is responsible for the apprentice's work (12-155-124(2)). Board Rule 1.2(E)(1)(c) and (2)(c) define direct supervision: "Direct supervision means that the supervising licensed master plumber, journeyworker plumber, or residential plumber is 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."
Ban on self-verification of experience hours
Rule 1.4(A)(3)(g) of 3 CCR 720-1 (rules effective 08/14/2026): "Applicants cannot verify their own experience." Experience is documented on the Board's experience verification forms, which must show exact dates of employment, a breakdown of commercial, residential and industrial work in hours and months, and the "Signature of the master plumber for, or a signatory authority of, the plumbing contractor, or employer" (Rule 1.4(A)(3)(a)-(c)). DPO: "Applicants shall not verify their own experience (even if currently licensed in another state)." The Affidavit of Experience form states "One month of plumbing experience must contain at least 163 hours of work" and marks Maintenance/Service work "Does not qualify for licensure." Hours required: Residential Plumber 3,400, Journeyworker Plumber 6,800, Master Plumber 8,500 (Rule 1.4(A)(3)(f)).
Plumbing contractor registration and master plumber of record
Under C.R.S. 12-155-108(3), operating as a plumbing contractor requires registration with the Board. A contractor must either be, or employ full-time, a master plumber "who shall be in charge of the supervision of all plumbing work performed by the contractor." The Guide: "The master plumber and company owner (if separate individuals) must sign an Acknowledgment of Responsibility Form." Statutorily, "A master plumber shall not be responsible for more than one plumbing contractor at a time" (C.R.S. 12-155-108(3)). "A master plumber shall notify the board within fifteen days after the master plumber's termination as a master plumber for a plumbing contractor"; failure to give notice "may lead to suspension or revocation of the master plumber license" (12-155-108(3)). The contractor then has "twenty days in which to hire another master plumber" (Rule 1.4(I)).
Contractor mandatory insurance coverage
C.R.S. 12-155-108(3) requires evidence that the applicant "has complied with the applicable workers' compensation and unemployment compensation laws of this state." The insurance minimums come from DPO's Plumbing Licensing Guide (they are not in the statute or the 08/14/2026 rules): "Property Damage Insurance (minimum $100,000) General Liability Coverage (minimum $300,000) Workers' Compensation Insurance (if you have employees)".
Contractor identification and vehicle display mandate (HB24-1344)
C.R.S. 12-155-125(1) (added by HB24-1344): "On and after July 1, 2025, a plumbing contractor shall display the following information on the plumbing contractor's vehicle or vehicles, billing materials, bid sheets, and website:" "(a) The plumbing contractor's Colorado registration identification number; and" "(b) The Colorado registration identification number for the master plumber attached to the plumbing contractor." Rule 1.4(N)(1) repeats the duty: display "their plumbing contractor registration number and the license number of their master plumber on their vehicles, billing materials, bid sheets, and website".
Contemporaneous review on-site enforcement
C.R.S. 12-155-120(10): inspections by the state, towns, cities, counties and qualified state institutions of higher education must include, for each project, a contemporaneous review to ensure compliance with 12-155-108 (licensing) and 12-155-124 (apprentices); "A contemporaneous review may include a full or partial review of the plumbers and apprentices working at a job site being inspected." An inspecting entity's standard procedures "need not require a contemporaneous review for each inspection of a project," but must let inspectors conduct "occasional, random, on-site inspections while actual plumbing work is being conducted, with a focus on large commercial and multi-family residential projects" and request documentation of who performed the work. Each inspecting entity must post its current procedures on its public website (12-155-120(10)(b)(III)).
Criminal history (HB24-1004)
DPO: "On June 4, 2024, Governor Polis signed HB24-1004 Ex-Offenders Practice in Regulated Occupations into law. Under this bill, if an applicant for a registration, certification, or license has a conviction for a crime, a regulator may only consider the applicant's conviction for a three-year period beginning on the date of conviction or the end of incarceration, if the applicant has not been convicted of any other criminal offense during the three-year period." The General Assembly's bill summary adds that the period runs from the conviction or end of incarceration, "whichever date is later"; that a conviction "directly related to the profession or occupation" may be considered after the three years; and that "An applicant's conviction for a crime does not, in and of itself, disqualify the applicant from being issued a registration, certification, or license." The Plumbing Licensing Guide: "Felony convictions do not automatically disqualify you but must be disclosed to the board with a full accounting of the events. The board considers these on a case-by- case basis."
Backflow prevention device testing and repair exemption (HB25-1077)
HB24-1344 (effective July 1, 2024) required "persons who are engaged in the business of installing, removing, inspecting, testing, and repairing backflow prevention devices to be licensed, except when installing or testing a stand-alone fire suppression sprinkler system" (bill summary). HB25-1077 (effective March 28, 2025) then amended C.R.S. 12-155-118(4): "Individuals who are engaged in inspecting, testing, or repairing backflow prevention devices are exempt from licensure under this article 155. Individuals who engage in the installation or removal of backflow prevention devices are not exempt from licensure under this article 155, except when the individuals are installing or replacing a backflow prevention device on a stand-alone fire suppression system, as defined in section 24-33.5-1202 (6)." HB25-1077 also added C.R.S. 12-155-126: "On and after July 1, 2025, a licensed plumber who installs, tests, inspects, repairs, or reinstalls a backflow prevention device shall affix a tag on the backflow prevention device" showing the business name and contact information, the plumbing contractor's registration number or the license number of the master plumber attached to the contractor, the date of service, and a description of the service.
Mandatory testing for long-term registered apprentices
C.R.S. 12-155-124(4), "contingent on the availability of existing resources within the department or the receipt of gifts, grants, and donations": (a)(I) "A plumbing apprentice who has been registered for at least six years, has completed six thousand eight hundred hours of practical training, and meets all other license requirements specified in section 12-155-110 shall take the license examination at least every two years in alignment with the license renewal cycle until the plumbing apprentice receives a passing score." (b) "A plumbing apprentice who has been registered for at least six years and who does not meet the license requirements specified in section 12-155-110 shall take the license examination at least once every two years in alignment with the license renewal cycle until the plumbing apprentice receives a passing score"; after passing, the apprentice must meet all other license requirements before a license issues. So every apprentice registered six years or more must test every two years. Under (a)(II), an apprentice who has failed in two consecutive two-year periods may request an exemption, which the board grants if it finds "legitimate educational or professional circumstances that justify the exemption." If an apprentice fails to take a required exam, the board may suspend the registration until the requirement is met (12-155-124(5)(a)).
License by endorsement (out-of-state plumbers)
C.R.S. 12-155-116: the board may license by endorsement a person licensed in another jurisdiction who has "credentials and qualifications that are substantially equivalent to requirements in Colorado for licensure by examination," and "may further require a waiting period of six months after the issuance of a license in another state." Rule 1.4(B)(1)(a) conditions: completion of a state or federally approved or registered apprenticeship program, or the required years and type of experience; "Successful completion of a comparable state plumbing examination based on the current or previous edition of the plumbing code adopted by the Board"; and an active license in the endorsing state. DPO's Applications page asks for a photocopy of a "currently held state (not city or county) issued license which you have held for a minimum of six (6) months" plus Affidavits of Experience. The Master Plumber application preview asks whether the applicant passed "a state licensing examination based on the 2018 or the 2021 IPC" and says "Licenses not issued by testing or by testing on a different version of the IPC or on a different code are not eligible for endorsement."
Temporary permits
C.R.S. 12-155-117: the board may issue a temporary permit to do the work of a journeyworker or residential plumber to an applicant who has shown the experience required to qualify for the examination and has applied for an examination; it expires "no later than thirty days after the date of the examination for which the applicant has applied or upon written notice by the board of the results of the examination, whichever date is earlier," and no permit issues to anyone who "has twice previously failed an examination or who has received two temporary permits."

Frequently asked questions

Do you need a state license to work as a plumber in Colorado?

Yes. Colorado licenses the individual tradesperson at the state level through the Colorado State Plumbing Board (DORA Division of Professions and Occupations). Under C.R.S. 12-155-108(1)(a), a person cannot engage in or work at the trade of a residential, journeyworker, or master plumber without an active state license or temporary permit. Anyone learning the trade must be registered as a Plumbing Apprentice within 30 days of hiring and work under direct supervision. In addition, any business entity performing plumbing contracting must hold a separate Plumbing Contractor registration with an assigned Master Plumber of record.

What is the difference between a Journeyworker Plumber and a Master Plumber in Colorado?

A Journeyworker Plumber requires 4 years (at least 6,800 hours) of practical plumbing experience and a passing score of 70% on the 100-question PSI journeyworker examination. A Master Plumber requires 5 full-time years (at least 8,500 hours) of practical plumbing experience and a passing score of 75% on the 120-question PSI master examination. Only a Master Plumber can serve as the designated qualifying supervisor for a registered Plumbing Contractor business.

Can a Colorado homeowner perform their own plumbing work without a license?

Yes, within statutory limits. C.R.S. 12-155-118(2) says nothing in the article requires an individual to hold a license to perform plumbing work on the individual’s own property or residence, or prevents a person from employing an individual to do routine repair, maintenance, and replacement of sinks, faucets, drains, showers, tubs, toilets, and domestic appliances and equipment equipped with backflow preventers. That does NOT apply if the property is intended for sale or resale by a person engaged in the business of constructing or remodeling, is rental property occupied or to be occupied by tenants, or is a commercial or industrial building; then the property is subject to the article’s licensing provisions. Permitted work is still inspected. C.R.S. 12-155-120(1)(a) says any plumbing or gas piping installation in new construction or remodeling or repair “must be inspected by a state plumbing inspector”, except (among other exclusions) where the local entity “conducts inspections and issues plumbing permits”. Under 12-155-120(1)(c)(I), “Prior to the commencement of any plumbing or gas piping installation, the person making the installation, who must be a qualified applicant, shall apply for a permit and pay the required fee”, and 12-155-120(11)(c) lists as a qualified applicant “A homeowner performing work on the homeowner’s home.” DPO’s Electrical and Plumbing Permits page offers “Purchase a Permit or Request an Inspection - Homeowner” and says “The State does not inspect in local jurisdictions having its own Plumbing Inspection Program.”

How many apprentices can a licensed plumber supervise in Colorado?

Under 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.” Board Rule 1.2(E) 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.”

Do you need state approval before scheduling a Colorado plumbing exam?

Under the current rule, no: 3 CCR 720-1 Rule 1.4(A)(1) says “Candidates must pass the required examination(s) before submitting an application to the Board,” and DPO’s online application previews say the exam must be passed through PSI before submitting the application. DPO’s Applications page and its May 2025 Licensing Guide still describe the older order (application approval first, then PSI scheduling information), so the board’s own pages disagree with its rule.

What continuing education (CE) is required to maintain a Colorado plumbing license?

Active Residential, Journeyworker, and Master Plumbers must complete at least 8 hours of continuing education during each licensure year (March 1 to February 28) (DPO; C.R.S. 12-155-112(3)(a); Rule 1.4(E)(3)). Within every 24-month period, at least 4 hours must relate to codes and no more than 2 hours may relate to safety training (Rule 1.4(E)(3)(d)(1)). Plumbers who received their initial license by examination during the current license period need no CE until after their first renewal. Licensees must keep CE records for at least six years.

Did Colorado change the title of Journeyman Plumber?

Yes. HB24-1344 changed the term “journeyman” to “journeyworker” throughout the plumbing practice act, effective July 1, 2025 (bill summary; C.R.S. source notes).

Can you test or repair backflow prevention assemblies without a plumbing license in Colorado?

Yes. Under HB25-1077 (effective March 28, 2025; C.R.S. 12-155-118(4)), individuals who inspect, test, or repair backflow prevention devices are exempt from plumbing licensure. Installing or removing backflow devices still requires a license, except installing or replacing a device on a stand-alone fire suppression system. On and after July 1, 2025, a licensed plumber who installs, tests, inspects, repairs, or reinstalls a backflow prevention device must affix a service tag to it (C.R.S. 12-155-126).

See every license and certification LicensingAtlas covers in Colorado.

Sources & verification

Last verified against these sources: October 9, 2026.

We re-check cited sources on a weekly schedule wherever a source can be fetched automatically. See what changed at the agencies, or every correction we have ever made.

LicensingAtlas states licensing and certification requirements categorically from official sources. It is a reference, not legal or career advice, and requirements change frequently — confirm details with the issuing board before you act.