complete guide to the C-36 plumbing contractors license in California, navigating the CSLB

C-36 Plumbing License: Everything You Need to Know!

Table of Contents

Man wearing a white hard hat fixing a toilet

Plumbing Contractors provide one of the most in-demand services in the construction industry.

Plumbing is a basic requirement within virtually all residential and commercial construction projects. 

With every boom in the construction industry, an increase in the demand for highly skilled plumbing services inevitably follows. 

Plumbing Contractors who are professional, highly skilled, and deliver excellent customer service can build a highly profitable business that services a basic human need.

This article will give you everything you need to know about the plumbing license, requirements, the California plumbing license test, study guides, and even how to fill out the C-36 License application.

What is a Plumbing Contractor?

The C-36 license is the classification required in the state of California for all persons looking to bid over $500 on projects that involve:

  • Plumbing Installation
  • Repair
  • Inspection and Maintenance
  • Design

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. This classification includes but is not limited to:

(a)Complete removal of waste from the premises or the construction and connection of on-site waste disposal systems;

(b)Piping, storage tanks and venting for a safe and adequate supply of gases and liquids for any purpose, including vacuum, compressed air and gases for medical, dental, commercial and industrial uses;

(c)All gas appliances, flues and gas connections for all systems including suspended space heating units. This does not include forced warm air units;

(d)Water and gas piping from the property owner's side of the utility meter to the structure or fixed works;

(e) Installation of any type of equipment to heat water, or fluids, to a temperature suitable for the purposes listed in this section, including the installation of solar equipment for this purpose; and 

(f)The maintenance and replacement of all items described above and all health and safety devices such as, but not limited to, gas earthquake valves, gas control valves, back flow preventers, water conditioning equipment and regulating valves.CSLB.GOV

Duties associated with the Plumbing License

a man using a wrench to tighten a pipe

Plumbing Contractors generally engage in a wide variety of duties including: 

  • Installation, repair, and maintenance of gas, sewer, and water lines
  • Installation, repair, and maintenance of water heaters and in some cases solar equipment
  • Removal of on-site waste
  • Estimation, bidding, accounting, and book-keeping
  • Repairing sinks and toilets
  • Water Conservation
  • Fuel gas piping and re-piping of buildings
  • Maintaining a safe Job site
  • Blueprint reading 
  • To obtain the C-36 plumbing license you will be tested on all areas of the trade so it will be essential to your success to make sure you are familiar and up to speed

Plumbing Contractors that hold the C-36 license can work in a variety of settings. They could be hired by a homeowner to do a simple repair.

Jobs you can do with a C-36 license!

Plumbing Subcontractor

They may also be subcontracted by a General Contractor who has placed a bid on a project that includes a full plumbing installation. 

Check out this article for an in-depth look at the General Contractor License

Online Practice Tests and Study Guides


Logo of the contractors state license board. logo contains an illustration of a paint brush, saw and cement truck

The Contractors State License Board (CSLB) is the governing body for all contractors in the state of California.

Their responsibility is to protect the consumer public and ensure that anyone charging over $500 for plumbing services is qualified and registered with the state of California. 

The C-36 License is issued to plumbing contractors by the CSLB. 

The State Board:

  • Administers Exams
  • Processes Applications
  • Maintains a database of all active and inactive contractor license numbers 
  • Sets up Sting Operations targeting unlicensed contractors

How to get a Plumbing License in California

To get a C-36 license in California, you have to meet the following requirements:

  • Be at least 18 years of age
  • Have a valid Driver's License or USA Issued Identification
  • Have a Social Security or ITIN #
  • Not Currently be on probation or parole

You must also have:

  • 4 Years Journey Level Experience
  • A Certifier to sign off on your experience
  • A way to prove your experience if the state asks for documentation

What is a Journeyman Plumber?

A plumber using a yellow wrench to tighten a pipe

A Journeyman plumber is someone who has gained experience working unsupervised full time for:

  • Plumbing Company
  • General Contractor
  • Union 
  • Someone that holds the C-36 License
  • Some Journeyman plumbers have also completed apprenticeship programs. 
  • A Journeyman plumber can perform all the duties associated with his or her trade. The state will want to see 4 full-time years of experience within the last 10 years. The years do not need to be consecutive, but they do need to be 4 years in total.

Signature of a Certifier

The following people may be used as a certifier to sign off on your experience when applying for the C-36 plumbing license:

  • Licensed General Contractor
  • C-36 Plumbing License Holder
  • Fellow Employee (within the last 10 years)
  • Former Supervisor (within the last 10 years)
  • Business Associate
  • Fellow Journeyman
  • Union Representative

Filling out the C-36 License Application

Your Qualifying Individual will also need to provide a brief but detailed description of your knowledge and skillset. The way this description is written will be critical to whether or not your application is accepted.

For example:

Writing: “Bob is a great guy, he fixed our toilet” will not be enough.

 The CSLB will want to see something like: “Bob has repaired plumbing problems, installed gas lines, sewer lines, installed bathroom fixtures, water lines, and re-piped buildings”

Work Experience for the C-36 Plumbing License

C-4 Contractors License

You must be prepared to submit documentation supporting the experience you claim to have. The Contractors State License Board gives you a few ways that you can prove your experience.

  • Tax Returns
  • Check Stubs
  • Contracts
  • Material Order Invoices or Receipts

The CSLB  receives thousands of applications per month so there is a good chance they won’t document your experience but if you are one of the applicants that get reviewed you will need to be ready to submit something. 

The CSLB does not accept pictures of projects.

C-36 License Application Processing, Fees, and Criminal History

The time it takes to get your application processed and assigned a test date fluctuates throughout the year.

Typically you can expect:

  • 6-8 Week Application Processing Time
  • 3-4 Week wait for an Exam date

I have seen some situations where applicants got their test date sooner and somewhere they got their test date much later.

The most common reasons your application would get held up are:

  1. Time of year (processing time slows down during the holidays) 
  2. Criminal History 
  3. Proving Experience
  4. Mistakes on your application 

Application Costs for the C-36 License

The Current CSLB fees are: 

Can you get a Contractors License with a Felony in California?

A picture of a fingerprint

Having a criminal record in no way stops you from getting a C-36 License. I have personally helped guys with all types of criminal records obtain multiple licenses.

The key is, to be honest on the application, even if the felony or misdemeanor happened years ago and even if it was expunged.

See the CSLB's verbiage below:

Just because you have been convicted of a crime does not automatically mean
your application will be denied. CSLB's Criminal Background Unit (CBU) reviews
all criminal convictions to determine if the crime is substantially related to
the duties, qualifications, and/or functions of a contractor. Since no two
conviction records are the same, they are reviewed on a case-by-case basis. The
criteria used by CSLB include whether the crime shows the present or potential
unfitness of an applicant or licensee to perform the functions authorized by
the license in a manner consistent with the public health, safety, or welfare.
In addition, CSLB reviews and considers any evidence of rehabilitation
submitted by the applicant or licensee. Please see the above link to the
California Code of Regulations sections 868 and 869 for more specific
information on the criteria for determining substantial relationship and

Learn more about the Background Check Process here:

BE 100% HONEST ON THE APPLICATION, because they will see everything anyway when you do fingerprinting. The CSLB handles criminal records on a case-by-case basis.

Remember, their responsibility is to protect the public.

In my experience, they are primarily concerned with criminal charges associated with Fraud, Embezzlement or Forgery

California Plumbing License Test

The exam will be:

  • 115 Questions of Contractor LAW
  • 115 Questions of Plumbing
  • 3 hours to complete each portion
  • Multiple choice exam done on a computer
  • Closed Book

For more information on what will be on the Contractor, LAW exam click here.

The Plumbing License (C-36 ) Examination is divided into five key sections:

1.    Planning and Estimation (22%)

  • Scope of work and code compliance
  • Pipe sizing and venting requirements
  • Shop drawings, plans, and specifications
  • Job site inspections
  • Coordination of projects
  • Water conservation
  • Cost estimation for materials, equipment, labor, and overhead

2.    Underground and Rough Systems (24%)

  • Excavation and underground installations
  • Piping layout and installation
  • Fuel gas piping
  • Insulation and system testing

3.    Finish Plumbing Installations (18%)

  • Plumbing fixtures
  • Water heaters
  • Shut-off valves
  • Specialty installations
  • Industrial and commercial piping 
  • Sanitary systems

4.    Service, Repair, and Remodel Plumbing Systems (19%)

  • Troubleshoot plumbing issues
  • Isolate leaks and damage
  • Repair plumbing
  • Retrofit plumbing
  • Disposal of plumbing materials

5.    Safety (17%)

  • Job site safety
  • Personnel safety
  • Environmental safety

Recommended Resources

CSLB Test Locations

The CSLB has exam centers all over the state of California. Once your
application is approved you will be given a list of locations you can go and
take the exam based on your zip code.

These are proctored facilities with cubicles where you take the exam on a
computer. The computer will have a calculator for your use. You will not be
able to bring in a phone, notes, or personal calculator to the exam center.

  • You get 18 months after your application is accepted to pass both examinations.
  • You must wait three weeks before retaking the state exam ($100 per retake)

Learn more about Contractor License LAW

C-36 license Study Guides and Exam Prep

a large plumbing installation on the floor going into the wall

Some things to remember:

  • The questions you will see on the exam may use outdated terms
  • Processes may be completely different from how things are done on the job site
  • You will see questions about things you may have never done before
  • Questions will be presented to you as if you are running a large-scale construction business with several employees and jobs happening all at once. 
  • Know all aspects of your trade

I have helped plumbers from all over the country get licensed in California. Many are startled by how strange the questions on the exam are.

Be as prepared as you possibly can.

Studying just 10 minutes a day consistently can dramatically increase your chances of passing the test on your first try.

Focus on and study ONLY the information that you need to pass the C-36 License.

Plumbing Apprenticeships

a plumber holding wires and a wrench preparing to work on a sink. apprenticeships are a great way to give yourself the foundation needed to get the plumbing license

An apprenticeship is an excellent way to learn your trade and set yourself up for a lucrative career as a plumber

If you don’t have the 4 years required journeyman-level plumbing experience to get a C-36 license, your journey begins here.

Generally, someone looking to get into this trade would begin by finding a union or plumbing apprenticeship program.

For a detailed explanation of this process, check out my article: Apprentice vs Journeyman.

Blueprint Reading Course

Plumbing contractors looking to get the C-36 license should know how to read construction blueprints at least at a basic level

It is critical for plumbing contractors to be able to read blueprints or at least be able to recognize lines and symbols.

  • Construction blueprints communicate important information about how a structure must be built as well as what materials are necessary for its construction.
  • Being comfortable with construction blueprints is an invaluable skill for all tradesmen but is especially important for those looking to get the C-36 license.
  • See our Free Blueprint Reading Course.

EPA Certification

Plumbing contractors may encounter lead based paint when working in a residential setting. The environmental protection agency has set guidelines for how lead paint must be contained. Plumbing contractors looking to get the C-36 license should get epa certified

Understanding how to safely contain lead-based paint when altering structures built before 1978 is required by the Environmental Protection Agency

The most profitable plumbing contractors are ones that position themselves as the experts and are the most knowledgeable and helpful to their clients. 


Getting the C-36 License can be a huge step up in your career if you are looking to start your own plumbing company or become an RMO!

The key is to take action and follow these steps from beginning to end. If you are looking to get work in another state you can find information here about plumbing contractor licenses in New MexicoUtahArizonaNevadaColorado, Louisiana, Alabama, Georgia, and Florida 

If you have found this article helpful feel free to drop a comment below and be sure to check back for updates!