The C-42 Sanitation License Guide

For contractors looking to commit their careers to keeping the world clean, fresh, and safe, the C-42 Sanitation License is the way to go.

In this comprehensive guide, we are going to spell out what this license is all about, how it relates to and differs from the C-36 Plumbing License, and also what you’ll need if you want to pass your C-42 Sanitation License exam the first time you take it!

What is the C-42 Sanitation License?

When you are not the one tasked with the responsibility of installing, maintaining, and repairing sanitation systems, it is very easy to take them for granted.

The average person doesn’t think too deeply about whether a sanitation system is functioning optimally – until that sanitation system no longer does! The expert contractors that we rely on in these cases, who quite honestly prevent society from full collapse, are C-42 Sanitation License holders.

These heroes are the ones we can trust to handle wastewater disposal, drainage, and plumbing fixtures related to those things. They have the Contractors State License Board (CSLB)’s blessing to work on residential, commercial, and industrial sanitation infrastructure throughout the state.

The C-42 Sanitation License vs. The C-36 Plumbing License

Let’s do a quick comparison to check the overlap between the C-42 Sanitation License and the C-36 Plumbing License. How are they similar? How are they different?

Both licenses are related to plumbing services, but the sanitation license requires a hyper-specialized focus on sanitation matters like sewage disposal, wastewater management, and drainage systems. This isn’t your run-of-the-mill check-the-pipes- situation – it’s a certification that allows for high-level infrastructure.

Meanwhile, C-36 plumbing contractors work on your everyday plumbing. They install and repair plumbing fixtures for commercial and residential projects – but they don’t involve overarching systems like wastewater management. They focus on general plumbing work like pipefitting and other such matters.

To put it plainly, the special C-42 license covers sanitation contractor work that goes beyond conventional plumbing services. Rarely do you see much overlap between these two licenses, as well, as they both cover different areas of expertise.

How to get the C-42 Sanitation License

The CSLB has laid out the criteria that applicants who are interested in becoming C-42 Sanitation License holders need to meet to be approved for the license.

The Basics
Contractors aiming for the sanitation license need to be at least 18 years old and they need a Social Security Number or ITIN to get going. Anyone who cannot work legally in the U.S. is ineligible for this California state-issued license.

There is a minimum level of work experience required for contractors who want to apply for the C-42 Sanitation License. In California, the CSLB requires about 4 years practical experience for sanitation contractor hopefuls.

A college degree can cover up to 3 of those years and self-employed experience is acceptable in California, but even with three years of schooling, you still need at least ONE year of on-the-job C-42 work experience.

Education & Exams
While there is no formal education requirement for pursuing this particular career path, you do have to pass the trade exam and the business law exam before that special C-42 license winds up in your hands.

There are online courses and in-person contractor schools dedicated to helping folks prepare for both the Sanitation System Exam and the Business Law Exam. These courses are designed to help sanitation contractors commit technical and safety knowledge to memory.

With these learning opportunities built into the process, contractors are primed for continuing education and any additional vocational training they might engage with later on in their careers.

There is a formal application that needs to be submitted to the CSLB for review. The application is comprehensive, covering work experience, education, and any other background details that are relevant to the CSLB’s mission to maintain high construction standards.

Sometimes a background check and financial proof that a contractor can afford the license play a role in whether or not the application is approved, but rarely.

The reason for evaluating financial stability is that application fees, renewal fees, the required insurance, and bonding are all necessary expenses to consider when embarking on this journey.

As far as the background check is concerned, rest assured that a very low percentage of applications are rejected because of an applicant’s criminal record.

Does a General Contractor Need a C-42 Sanitation License?

Since general contractors oversee various aspects of construction projects, situations may come up where they’d benefit from having a C-42 Sanitation License.

Rather than subcontract the work, a general contractor might want to keep their project’s timeline and budget tight by stepping in to complete the C-42 classified work themselves.

Consider it a case-by-case type of decision. If a general contractor engages with sanitation systems to a substantial degree, it might be worth it for them to go through with the whole process and then maintain their C-42 Sanitation License throughout their career.

In most cases, however, it’s going to be best for them to rely on subcontractors or sanitation specialists on their established crew to take care of all that business.

Anyone tasked with the actual installation, repair or maintenance of a sanitation system needs to prioritize safety and quality and they must comply with CSLB standards and local building codes.


The C-42 Sanitation License is a specialized credential issued by the CSLB, but the screening process is not an impossible one to cycle through.

Contractors just starting out or general contractors who want to be legally cleared to install, update, or fix sanitation systems need the C-42 Sanitation License before they can do so.

Once a person meets the experience requirements and passes the necessary exams, they’ll need to prepare themselves for the financial responsibility that comes with being a C-42 license holder.

Provided that they can keep up with the licensing requirements set by the CSLB, sanitation contractors need only to implement responsible sanitation practices that comply with CAL/OSHA safety and local public health regulations.

And sanitation professionals share the duty of mitigating negative impacts on environmental integrity.