What is a C61 / D9 Drilling, Blasting and Oil Field Work Contractor?

A drilling contractor working on an oil field

C-61 Limited Specialty Classification

The C-61 Limited Specialty License is an umbrella term for all licenses that may fall under a more obscure category of construction work.  

If your skill set or business is limited to one particular portion of trade work, you could obtain a C-61 limited specialty license to contract over $500 for your services legally.

Typical duties of Drilling Contractors

D-9 drilling contractors are sometimes referred to as: directional or horizontal drilling contractors, oil drilling contractors, or drilling and blasting contractors.

The C-61 / D-9 classification covers all of these duties. Drilling contractors typically engage in:

  • Core and post hole drilling
  • Foundation and limited access drilling
  • Septic system and seepage pit drilling
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    Operating blast hole drilling rigs
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    Working on oil fields
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    Maintenance of heavy duty machinery including bores and rigs
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    Site evaluation and geological testing
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    Pulling permits for drilling
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    Returning soil to its natural state
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    Adhering to environmental regulations
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    Bidding, cost calculation, and accounting
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    Maintaining a safe job site

To drill water wells and engage in piping specifically you will need to obtain a C-57 Well Drilling License, however if your business is primarily drilling or oil field specialty work you can obtain the D-9 License.

Drilling Subcontractor

A metal drill penetrating the ground

In a construction setting, a General Engineering Contractor may hire a drilling contractor specifically for their expertise and equipment.

As a result, a general contractor ensures that the drilling phase of the project is executed correctly.

Learn more about the General Engineering License!


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. 

They ensure that anyone charging over $500 for construction services is qualified and registered with the state.

The C-61/D-9  Drilling contractor license is issued to contractors by the CSLB. 

C-61 / D-9 Drilling Contractor License Requirements

Drilling contractors in California must prove a minimum of 4 years journeyman level experience and pass a law exam.

To qualify for an exam date you must meet the 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 #
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    Not Currently be on probation or parole

You must also have:

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

What is journey level experience?

A contractor operating a drill. drilling contractors must have 4 years of journey level experience to get licensed in California

Journeyman level experience means that you have worked unsupervised full time for a drilling service, or for a contractor that holds the D-9 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. 

Signature of a Qualifying Individual

The following people may act as a Qualifying Individual when applying for your D-9 drilling contractor license

  • Licensed General Contractor
  • C-61 / D-9 Drilling License Holder
  • Former Supervisor (within the last 10 years)
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    Fellow Employee (within the last 10 years)
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    Business Associate
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    Fellow Journeyman
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    Union Representative

How to fill out the Contractor License application

In addition, your Qualifying Individual will need to provide a brief but detailed description of your knowledge and skillset.

The way this description is written is critical to whether or not your application gets accepted. For example: 

“Hank and his team drilled our post holes” is not descriptive enough.

 The CSLB will be looking for something like: 

"Hank has operated various types of directional drilling rigs, he has engaged in oilfield work, hill side drilling, placement of charges, blasting and site dewatering" etc.

Most importantly, the description written by your qualifying individual has to include the core skills required a drilling contractor.

Work experience for the Contractor License

A red truck with a large drill attached at the back, penetrating the earth in a large pasteur

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 which include:

  • 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.

However, 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 some where 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 

Contractor License Costs

The Current CSLB fees are: 

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

person holding a pen filling out a criminal background check form

Having a criminal record in no way stops you from getting the a drilling contractor license.

Thousands of tradesman get licenses each year despite their criminal records. Be honest on the application. Even if the felony or misdemeanor happened years ago and even if it was expunged. 

BE 100% HONEST ON THE APPLICATION, because the CSLB sees everything when you do live scan fingerprinting. The CSLB handles criminal records on a case by case basis. Remember, the state board's responsibility is to protect the public.

In my experience, the CSLB are primarily concerned with criminal charges dealing with fraud, embezzlement, forgery, and financial related crimes.

The Contractor License Exam

Contractor licenses are broken down into four categories:

1) A-General Engineering

2) B-General Building

3) C-Specialty classes

4) C-61 / D-Limited Specialty classes

Each category of license except the D-Limited Specialty license class requires that you pass a TRADE exam. C-61 Classification licenses do not have trade portions.

You must only pass a LAW exam. The exam is:

  • 115 Questions on Contractor LAW
  • 3 Hours to complete
  • Multiple choice, taken on a computer
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    Closed Book

The Law Examination is divided into eight major sections:

1. Business Organization (10%)

  •  Company organization
  •  Project organization

2. Business Finances (15%)

  • Cash management
  • Budget and planning
  • Taxes
  • Financial reporting

3. Employment Requirements (12%)

  • Employment regulations
  • Evaluation and record-keeping
  • Payroll

4. Bonds, Insurance, and Liens (10%)

  • Bonds
  • Workers’ compensation insurance
  • Liens and other remedies
  • Other insurance

5. Contract Requirements and Execution (23%)

  • Bidding
  • Cost control
  • Contracts
  • Payments

6. Licensing Requirements (8%)

  • Business license
  • Contractor’s license
  • Activity regulation

7. Safety (15%)

  • Training and reporting requirements
  • General safety
  • Hazardous/unknown materials

8. Public Works (7%)

  • Prevailing wage requirements
  • Bonding requirements
  • Insurance requirements

Learn more about Contractor License LAW!

Recommended Resources

CSLB Test Locations

featured image for a blog post about how to get the Drilling contractor license

The CSLB has testing locations in the following cities:

  • Berkeley 
  • Fresno 
  • Norwalk 
  • Oxnard
  • Sacramento 
  • San Bernardino 
  • San Diego  
  • San Jose
  • The CSLB will assign you a testing center based on your location
  • The test is not available online
  • The CSLB allows you to bring a pre-approved translator with you 
  • The CSLB will grant you 18 months after your application is accepted to pass the law test 
  • You must wait three weeks before retaking the state exam ( $60 per retake )

California Contractors License Exam Prep

  • Getting your concrete services contractors license is a smooth process if you have the right information. 
  • It can be confusing to see un-familiar terms used to describe tools or job site practices. The Contractor LAW exam covers a number of different topics.
  • Questions are presented to you as if you are running a large scale remodeling business with multiple employees.
  • Being prepared and knowing what to study is the most important thing you can do in ensuring your success on the contractor license exam.

Drilling Apprenticeships

three construction workers wearing yellow hard hats on a job site looking up at a drill about to penetrate the earth

If you do not have the experience required to get the C-61/D-6 Concrete services Contractor license, not to worry!

Your journey begins here. Generally someone looking to become licensed contractor would want to look into an apprenticeship for find an experienced person to work with.

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

Blueprint Reading Course

several construction contractors analyzing blueprints at a table. drilling contractors looking to get the C-57 license should know how to read construction blueprints

It is critical for drilling contractors to be able to read designs and symbols on construction blueprints.

If installation or repair is part of a larger project, being able to execute their duties within the larger scope of the job is essential. 

They also communicate what materials were used for its construction. Reading blueprints is an invaluable skill for all tradesman but can be especially important for concrete services contractors.

Check out our Free Blueprint Reading Course!

OSHA Certification

two construction workers on top of a steel beam. drilling contractors should be familiar with OSHA safety regulations

Occupational Safety Hazard Association

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

That equals about 1 and 5 worker deaths on average. Professionals in the landscaping and tree removal industry must take pre-caution to prevent falls and injury.

Drilling can be dangerous, especially if your workers are not properly trained. For employment with a drilling company you may be required that you have completed some level of OSHA training.

 Learn more about OSHA Training!


Getting the C-61/D-9 Drilling 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! T

he 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!

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