C-36 – Plumbing Contractor License
California C-36 Plumbing Contractor License Exam Preparation
The C-36 Plumbing Contractor license is one of the most essential and in-demand specialty classifications in California. From residential repiping projects to commercial installations, licensed plumbing contractors are needed for virtually every type of construction project.
At Contractors State License Services (CSLS), we've helped thousands of aspiring plumbing contractors pass their CSLB exams and build successful businesses. With over 40 years of experience and a 99% pass rate, we offer the most comprehensive exam preparation programs in California.
Why Choose CSLS for Your C-36 License?
• 99% exam pass rate
• 40+ years helping contractors succeed
• 25+ convenient California locations
• Live instruction, online, and home study options
• Expert instructors with real-world plumbing experience
What Is a C-36 Contractor License?
Official CSLB Definition
"A plumbing contractor provides a means for a supply of safe water, ample in volume and of suitable temperature for the purpose intended and the proper disposal of fluid waste from the premises in all structures and fixed works."
— California Code of Regulations Title 16, Division 8, Article 3
In practical terms, a C-36 license allows you to install, maintain, and repair all water supply systems, drainage systems, gas piping, water heaters, and related equipment. This covers everything from residential plumbing to complex commercial and industrial systems.
Work You CAN Perform with a C-36 License
With a California C-36 Plumbing contractor license, you can legally perform:
- Water supply systems – All piping from the meter to fixtures, including pressure systems
- Drain/waste/vent (DWV) systems – Complete drainage and venting for all structures
- Gas piping and appliances – Gas lines from meter to appliances, including water heaters and ranges
- Water heaters – All types including tank, tankless, solar, and heat pump water heaters
- Backflow preventers – Installation, testing, and repair
- Medical gas systems – Piping and equipment for healthcare facilities
- On-site waste disposal – Septic systems and alternative waste treatment
- Earthquake shut-off valves – Gas and water safety devices
- Water conditioning equipment – Softeners, filters, and treatment systems
- Vacuum and compressed air – Piping systems for commercial/industrial use
Work You CANNOT Perform
Even with a C-36 license, there are limitations:
- Forced warm air heating – Requires C-20 HVAC license
- Fire suppression systems – Requires C-16 Fire Protection license
- General building construction – Multi-trade projects require B license
- Boiler/steam fitting – May require C-4 license depending on scope
- Well drilling – Requires C-57 license
Important: Many plumbing contractors work alongside general contractors (B license holders) as subcontractors on larger construction projects.
C-36 vs C-4: Understanding the Difference
Some plumbing work overlaps with the C-4 (Boiler, Hot Water Heating and Steam Fitting) classification. Here's how to understand which license you need:
| Feature | C-36 - Plumbing | C-4 - Boiler/Steam |
|---|---|---|
| Water Supply | Yes | Limited |
| DWV Systems | Yes | No |
| Gas Piping | Yes | Limited to boilers |
| Tank Water Heaters | Yes | Limited |
| Boilers | Limited | Yes |
| Steam Systems | No | Yes |
| Hydronic Heating | Limited | Yes |
| Process Piping | Limited | Yes |
Our recommendation: Most residential and commercial plumbing work requires a C-36 license. The C-4 license is primarily for contractors specializing in boiler systems, steam fitting, and hydronic (radiant) heating systems.
C-36 License Exam Preparation
The CSLB examination for a C-36 Plumbing contractor license consists of two parts:
- Law and Business Exam – 115 multiple-choice questions covering California contractor law, business management, and safety regulations
- Trade Exam – 100 multiple-choice questions on plumbing knowledge and skills
Trade Exam Topics
The C-36 Plumbing trade exam covers:
- California Plumbing Code (CPC) – State-specific requirements and amendments
- Uniform Plumbing Code (UPC) – Industry standards and best practices
- Drain/waste/vent design – Sizing, slope, and venting requirements
- Water supply design – Pressure, flow rates, pipe sizing
- Gas piping – Sizing, materials, testing, and safety
- Fixture installation – Proper methods and code requirements
- Water heater installation – Tank, tankless, solar systems
- Blueprint reading – Plumbing symbols, schedules, specifications
- Estimating and bidding – Material takeoffs, labor calculations, job costing
- Safety and OSHA – Trenching, confined spaces, hazardous materials
Available Course Options
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C-36 License Requirements
Experience Requirements
To qualify for a C-36 Plumbing contractor license, you must have:
- 4 years of journeyman-level experience in plumbing work within the past 10 years
- Experience must be verifiable through employer certification or other documentation
- Experience in the type of plumbing work you'll be performing (residential, commercial, or industrial)
Note: California does not require a separate journeyman plumber certification, but your experience must be at the journeyman level (working independently, not as an apprentice).
Alternative Pathways:
- Education can substitute for up to 3 years of experience (degree-dependent)
- Technical training programs may count toward experience
- Military plumbing experience may qualify
- Apprenticeship completion plus additional experience
Application Process
- Verify Eligibility: Confirm you have 4 years of qualifying plumbing experience and are at least 18 years old
- Complete Application: Fill out the CSLB application form accurately and completely
- Pay Application Fee: Submit the $450 application fee to CSLB
- Background Check: Complete fingerprinting and criminal background check
- Experience Verification: Have employers certify your plumbing work experience
- Schedule Exams: Once approved, schedule your Law & Business and Trade exams
- Pass Exams: Score 72% or higher on both examinations
- Obtain Bond: Secure a $25,000 contractor bond
- Pay License Fee: Submit the $200 initial license fee
Fees and Costs
| Application Fee | $450 |
| Initial License Fee | $200 |
| Contractor Bond | $25,000 (premium varies) |
| Renewal Fee (every 2 years) | $450 |
Need help with your application? CSLS offers Application Processing Services to ensure your application is complete and accurate, reducing delays and rejections.
Career Outlook for Plumbing Contractors
California's plumbing industry continues to show strong growth, driven by several key factors:
- Median Annual Salary: $68,730 for plumbers in California, with experienced contractors earning significantly more (BLS, 2023)
- Job Growth: 5% projected growth through 2032 (as fast as average)
- High Demand Areas:
- Water conservation – California's drought conditions drive demand for efficient systems
- Repiping – Aging homes need copper or PEX repipes
- Tankless water heaters – Growing demand for energy-efficient solutions
- ADU construction – Accessory dwelling units require full plumbing systems
- Commercial construction – New buildings and tenant improvements
- Service and repair – Steady demand for maintenance work
- Self-Employment: Many C-36 holders operate their own contracting businesses
With California's strict water efficiency requirements and aging infrastructure, licensed plumbing contractors are positioned for long-term career success.
Source: Bureau of Labor Statistics, California Employment Development Department
Frequently Asked Questions
What is a C-36 contractor license in California?
A C-36 Plumbing contractor license allows you to install, maintain, and repair water supply systems, drain/waste/vent systems, gas piping, water heaters, and on-site waste disposal systems in residential, commercial, and industrial settings.
How do I get a plumbing contractor license in California?
You need 4 years of journeyman-level plumbing experience, pass the CSLB Law & Business and Trade exams, obtain a $25,000 contractor bond, and complete the application process. CSLS provides comprehensive exam preparation to help you pass on your first attempt.
What work can a C-36 contractor perform?
C-36 contractors can install water supply systems, drain/waste/vent systems, gas piping and appliances, water heaters (including solar and tankless), backflow preventers, medical gas systems, septic systems, and earthquake shut-off valves.
What's the difference between a journeyman plumber and a C-36 contractor?
A journeyman plumber works for a licensed contractor. A C-36 contractor can own their own business, bid on projects, pull permits, and contract directly with property owners. You need journeyman-level experience to qualify for the C-36 license.
How hard is the C-36 contractor license exam?
The C-36 exam has two parts: Law & Business (115 questions) and Trade (100 questions). The trade exam covers the California Plumbing Code, system design, installation methods, and safety. With proper preparation, most students pass. CSLS has a 99% pass rate.
How much does a C-36 contractor license cost?
Total costs include: application fee ($450), initial license fee ($200), contractor bond ($25,000 minimum), and exam prep courses. Total investment is typically $1,500-$3,000.
What experience do I need for a C-36 license?
You need 4 years of journeyman-level experience in plumbing work within the last 10 years. Education from accredited programs can substitute for up to 3 years of experience.
Can a C-36 contractor install water heaters?
Yes. C-36 contractors can install all types of water heaters including tank, tankless, solar, and heat pump water heaters. This includes the water connections, gas connections, and venting.
Ready to Get Your C-36 License?
Join thousands of successful plumbing contractors who passed their CSLB exam with CSLS. With 40 years of experience and a 99% pass rate, we're California's most trusted contractor licensing school.
Whether you prefer live classroom instruction, online self-study, or home study materials, we have a program that fits your learning style and schedule.
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