Construction / Plumber License / Hawaii
- Hawaii
- Plumber License
- C-37 Plumbing Contractor
- Updated Oct 2026
How to Get Your Hawaii Plumber License
What the Hawaii C-37 plumbing contractor license covers, who qualifies, and what to expect on the two state exams.
Last updated October 27, 2026 from Hawaii Board of Electricians and Plumbers requirements
Application fee
$50
Plus $80 per PSI exam (two exams)
Exam time
6 hrs
Two exams, 180 minutes each
Time to get license
Varies
Experience requirement not stated in our sources
Continuing ed
Not stated
Confirm with the Board
Overview
Do you need a Hawaii plumber license?
Yes, if you install, repair or alter plumbing systems as a contractor in Hawaii. The C-37 license covers complete plumbing systems in buildings where people or animals live, work or gather.
License required when
- Water supply, hot water and wastewater piping
- Fuel gas piping and wastewater treatment systems
- Backflow prevention assemblies, fixtures and venting
- Medical gas, vacuum and air piping, spas, pools, lawn sprinklers and irrigation
- Solar hot water heating systems
Common exceptions
- Fire sprinkler systems may only be installed under a licensed mechanical engineer or licensed fire protection contractor
- Our source notes don’t list other exemptions, so confirm with the Board
Penalties for unlicensed work
Plumbing contracting without a license puts you at risk of discipline and penalties from the state. Get licensed before you bid or start work.
Your fast-track Hawaii plumber license checklist
The Hawaii application, one page
- Proof you’re at least 18
- Employment with a licensed contracting entity
- Approved exam application
- Passing Business & Law score (75%)
- Passing C-37 Plumbing Contractor score
- License application to DCCA
Types
Hawaii plumber license types and classifications
Our sources cover one plumbing classification: the C-37 Plumbing Contractor license.
C-37
Contractor
Plumbing Contractor
Installs, repairs and alters complete plumbing systems, including fuel gas, wastewater treatment, medical gas, pools, irrigation and solar hot water.
Exam
C-37 + Business & Law
Limit
Not stated
Requirements
Hawaii plumber license requirements, class by class
C-37 applicants must meet a minimum age, pass two exams and be employed by a licensed contracting entity.
| Requirement | C-37 Plumbing Contractor |
|---|---|
| Minimum age | 18 |
| Character | Good reputation for honesty, truthfulness, financial integrity and fair dealing |
| Trade exam | C-37 Plumbing Contractor exam |
| Business exam | Business & Law exam |
| Employment | Employed by a licensed contracting entity |
| Experience | Not stated |
Steps
How to get your Hawaii plumber license, step by step
- Check you qualifyBefore you apply
You must be at least 18, have a good reputation for honesty and fair dealing, and be employed by a licensed contracting entity. - Apply for exam approvalPre-approval required
Submit a completed application to the state. You can’t schedule either exam until it’s approved. - Schedule with PSIAfter approval
Book through PSI or call 833-333-4754. Test centers are in larger cities across the state. - Pass Business & LawExam day
80 questions in 180 minutes, closed book. You need 75% to pass. - Pass the C-37 trade examExam day
80 questions in 180 minutes, closed book. - Apply for your licenseAfter you pass
Apply through the Department of Commerce and Consumer Affairs (DCCA) to receive your license.
Exam
What to expect on the Hawaii plumber exam
You sit two closed-book exams with PSI: Business & Law and the C-37 Plumbing Contractor exam. No books are allowed in the room.
Format
Closed book
Questions
80 + 80
Passing score
75% (B&L)
Exam vendor
PSI
Scoring & content
- Business & Law: 80 questions, 180 minutes, 75% to pass
- C-37: 80 questions, 180 minutes; passing score not stated
- Trade topics: fixtures, storm drainage, fuel gas, water supply, water heaters, DWV, plumbing math, medical gas, OSHA
- References include the 2018 Uniform Plumbing Code and 2018 International Fuel Gas Code
- Business topics include contracts, estimating, lien law, labor law, tax and public works law
Retake policy
- You can retest as soon as two business days later, depending on space
- Each attempt is a new $80 PSI exam fee
- State approval is required before you schedule
Exam references · Closed book
Hawaii’s contractor exams are closed book, so you can’t bring any books into the testing room. Use these references to study for the C-37 Plumbing trade exam and the Business & Law exam.
| Book | Edition | Use |
|---|---|---|
| Uniform Plumbing Code (UPC) — C-37 Plumbing exam | 2018 | Study only |
| International Fuel Gas Code (IFGC) — C-37 Plumbing exam | 2018 | Study only |
| Mathematics for Plumbers and Pipefitters — C-37 Plumbing exam | 8th edition | Study only |
| OSHA 29 CFR 1926 Construction Industry Regulations — C-37 Plumbing exam | Not stated | Study only |
| NASCLA Contractor’s Guide to Business, Law and Project Management, Hawaii edition — Business & Law exam | 1st edition | Study only |
| Hawaii Revised Statutes Chapter 103, Expenditure of Public Money and Public Contracts — Business & Law exam | Not stated | Study only |
| Hawaii Revised Statutes Chapter 104, Wages and Hours of Employees on Public Works — Business & Law exam | Not stated | Study only |
| Hawaii Administrative Rules Title 12, Chapter 22, Wage Determinations — Business & Law exam | Not stated | Study only |
Prep
Best Hawaii plumber exam prep, compared
We haven’t compared prep courses for this exam yet.
Costs
How much does a Hawaii plumber license cost?
| Item | Type | Estimate |
|---|---|---|
| Application fee | Fixed | $50 |
| Business & Law exam (PSI) | Fixed | $80 |
| C-37 trade exam (PSI) | Fixed | $80 |
| Initial license fee (sole proprietor or entity) | Fixed | $663 or $494 |
| State fees and exams | Application, two PSI exams and the sole proprietor or entity license fee; excludes credit report and insurance | $704–$873 |
Fees from the Hawaii Contractors License Board application and FAQ, HAR §16-53-17 and the PSI Hawaii contractor candidate bulletin, checked October 2026. The license fee is $663 if you’re licensed October 1 of an even year through September 30 of an odd year, and $494 otherwise ($438 or $334 for a responsible managing employee).
Reciprocity
Does Hawaii accept out-of-state plumber licenses?
Our sources don’t list any reciprocity agreements for Hawaii plumbing licenses.
No reciprocity agreements
None are listed in our sources. Plan to apply as a new applicant and pass both exams, and confirm with the Board.
Local
Do Hawaii cities and counties have their own plumber licensing rules?
Your license comes from the state, but county building departments still handle permits and inspections.
State handles
- Licensing and exam approval
- Exams, through PSI
- Discipline of licensees
City & county handle
- Plumbing permits
- Inspections
Governance
Who regulates plumbers in Hawaii
Licensing authority
Hawaii Board of Electricians and Plumbers
808-586-3000
Oversight responsibilities
- Reviews plumbing license applications
- Approves applicants to sit for state exams
- Issues and renews licenses
- Disciplines licensees
Maintenance
How to renew your Hawaii plumber license and keep it active
Hawaii contractor licenses renew every two years. The biennial renewal fee is $353 for a sole proprietor or contracting entity and $208 for a responsible managing employee. Our sources don’t state CE rules for plumbing contractors, so check with the Board.
Renewal cycle
Not stated
CE hours
Not stated
Renewal fee
$353 ($208 RME)
Late penalty
$50 plus renewal fee
FAQ
Hawaii plumber license FAQs
What exams do I need for a Hawaii plumbing license?
Two: the Business & Law exam and the C-37 Plumbing Contractor exam. Each has 80 questions and a 180-minute limit.
Are the Hawaii plumbing exams open book?
No. Both exams are closed book.
What score do I need to pass Business & Law?
75% correct.
Who gives the Hawaii plumbing exam?
PSI. You need state approval of your application before you can schedule.
How old do I have to be?
At least 18.
Does the C-37 license cover fire sprinklers?
Only under the supervision of a licensed mechanical engineer or licensed fire protection contractor.
Sources
Official sources for the Hawaii plumber license
- Hawaii Board of Electricians and Plumbers
- PSI, Hawaii trade exams
- HRS Chapter 103, Expenditure of Public Money and Public Contracts
- HRS Chapter 104, Wages and Hours of Employees on Public Works
- HAR Title 12, Chapter 22, Wage Determinations (PDF)
- 2018 Uniform Plumbing Code
- Hawaii Contractors License Board, Requirements and Application, Sole Proprietor (PDF)
- Hawaii Contractors License Board, Contractor FAQ (fees) (PDF)
- HAR Title 16, Chapter 53, Fees (PDF)
- PSI, Hawaii Contractor Examinations Candidate Information Bulletin
Last updated October 27, 2026. Spot something out of date? Tell us.
Exam Insiders is an independent guide and is not affiliated with the Hawaii Board of Electricians and Plumbers.