featured image for a blog post explaining how to get the C-42 sanitation systems contractor license

C-42 License: Sanitation Systems Contractor

Table of Contents

Sanitation systems contractors provide one of the most important services in the construction industry. Sometimes referred to as:

  • Sewer Contractors
  • Septic System Contractors 
  • Sanitation Engineers
  • Waste management consultant

Jobs You Can Do With a C-42 License

A sanitation contractor using a high pressure pump to drain a septic tank

Functioning sanitation systems are one of the cornerstones of living in modern society.

With 7 billion people on the planet, never at any point in history has there been more of a demand for efficient sanitation systems than now. 

In this article, we will go into detail about everything you need to know about C-42 license requirements, the exam, study guides, and even how to fill out the license application.

What is a Sanitation Systems Contractor?

“A sanitation system contractor fabricates and installs cesspools, septic tanks, storm drains, and other sewage disposal and drain structures. This classification includes the laying of cast-iron, steel, concrete, vitreous and non-vitreous pipe and any other hardware associated with these systems”-CSLB.GOV

The C-42 is the classification required in the state of California for all persons looking to bid on the fabrication and installation of sanitation systems where the cost of labor and materials exceeds $500.

Duties associated with the C-42 license

Sanitation systems contractors engage in a wide variety of duties including:

  • Installing storm drains, catch basins, septic tanks, and mainline sewers
  • Installing seepage pits, drain fields, and clarifies for industrial waste
  •  Complete design and fabrication of water treatment systems
  • Building brick manholes
  • Maintaining and repairing various types of water treatment systems
  • Estimating, bidding, creating invoices, and accounting
  • Maintaining job site safety
  • Working in compliance with environmental safety codes

To get the sanitation systems classification, you will have to be familiar with all aspects of sanitation systems.


Logo of the CSLB. Illustration of a saw, paint brush and cement truck

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

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

The C-42 license is issued to contractors by the CSLB.

The CSLB administers applications, exams, and maintains a database of all active and inactive contractor license numbers which are public domain.

General Engineering Contractor License

Sanitation companies that hold the C-42 contractor license often are contracted in a public works setting. 

Meaning they are being paid from public taxpayer funds to complete sanitation systems projects.

They may in some cases work with a company or property owner.

However,  in many cases, they work as a sub to a General Contractor or General Engineering Contractor to continually engage sanitation systems to work for multiple projects over an extended period of time. 

two construction workers cutting a pipe with a power saw

General Contractors oversee that the Sanitation systems subcontractor has executed their duties in adherence to the code as well as in adherence to environmental safety standards.  

Learn more about the General Engineering Contractor License!

How to get the C-42 license in California

To get a sanitation contractor license in California, you must meet the following basic 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 Journey level experience?

a large water treatment facility. Getting a C-42 license for sanitation contractors requires that you have 4 years journey level experience

Journeyman-level experience means that you have worked unsupervised full-time for a sanitation company, or contractor that holds the C-42 License.

  • A journeyman can perform all of the duties associated with his or her trade.

The CSLB will want to see four full-time years over the last ten years. The years do not need to be consecutive, but they do need to be four years in total. 

Filling out the Sanitation Contractor License Application

Your Qualifying Individual will also need to provide a brief but detailed description of your knowledge and skill set.

The way this description is written will be critical to whether or not your application is accepted.

For example:

“Tom is a great guy, he replaced our storm drain” is not descriptive enough.

 The CSLB will want to see something like:

“Ed has installed septic tanks, pre-cast manholes, catch basins, clarifiers for industrial waste and drain fields”.

The description written by your qualifying individual will need to include the core skills required a sanitation contractor.

Work experience for the Contractor 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.

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-42 License

The Current CSLB fees are: 

Can you get a Contractor's License with a Felony in California?

Having a criminal record in no way stops you from getting a C-42 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.

two law books and a wooden gavel laying on top of a white surface. sanitation contractors looking to get the C-42 license should be honest about their criminal history

BE 100% HONEST ON THE APPLICATION, because they will see everything anyway when you do fingerprinting.

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:

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, and Forgery.

California Contractor License Exam Prep

The exam will be:

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

Recommended Resources

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

The Sanitation System (C-42 sanitation contractor license) Examination is divided into five major sections:

1. Planning and Estimation (27%)

  •  Planning sanitation systems
  •   Estimating sanitation systems

2. New Septic System Installation (26%)

  • Installing septic tanks
  • Installing leach lines and seepage pits
  • Testing and grading over septic systems
  • Installing alternative treatment systems
  • Specialty sanitation systems

3. Sewer Lateral Installation and Repair (10%)

  • Installing sewer laterals
  • Maintaining and repairing existing sewer systems

4. Septic System Maintenance and Repair (10%)

  • Troubleshooting existing septic systems
  • Removing or repairing existing septic systems
  • Maintaining existing septic systems

5. Safety (27%)

  • Employee training and safety
  • Job site safety

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.

  • The state exam is not available online 
  • You are allowed to bring a pre-approved translator with you 
  • The CSLB will grant you 18 months after your application is accepted to pass both examinations 
  • ($100 per retake) 

Learn more about Contractor License LAW!

Sanitation Contractor License Practice Exams

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

water treatment tanks outside at a treatment facility

I have helped all types of tradesmen from various backgrounds and experience levels get licenses. Most are startled by how different the subject matter on the state exam is from their years of first-hand experience.

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.

Construction Apprenticeships

water treatment system

If you don’t have the 4 years required journeyman level experience to obtain a C-42 License, not to worry. Your journey begins here.

Ornamental Metalwork is a highly specialized trade with an unlimited amount of opportunity. 

Generally, someone looking to become a metalworks contractor would want to look into an apprenticeship or find a skilled tradesman to learn under. 

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

Blueprint Reading Course

blueprint reading is a critical skill for anyone looking to get the C-42 license

It is critical for the sanitation contractors to be able to read construction blueprints. Understanding complex designs and layouts are a fundamental part of the job sanitation contractors do.

Quickly interpreting construction blueprints and executing your duties safely is an invaluable skill for all tradesmen but is especially important for sanitation Contractors.

If you are also looking to get a sanitation systems license, you will absolutely want to be familiar with construction blueprints.

Check out our Free Blueprint Reading Course!

OSHA Certification

two construction workers working high up on a beam. sanitation contractors looking to get the C-42 license should be familiar with OSHA safety standards

Occupational Safety Hazard Association

Statistically, 21% of all work-related fatalities are in construction.

That equals about 1 and 5 worker deaths on average.

 In the construction industry, the leading cause of worker deaths is reported as falls, struck by an object, electrocution, and caught-in/between.

The sanitation construction industry can be dangerous, especially if your workers are not properly trained.

For employment with a sanitation contractor, it is typically required that you have completed some level of OSHA training.

Learn more about OSHA Training


Getting the C-42 sanitation license can be a huge step up in your career if you are looking to start your own company or become an RMO for an existing firm!

The key is to take action and follow these steps from beginning to end. 

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