Rotary drilling & coring services
Highly experienced and dependable personnel
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Geotechnical & environmental subsurface investigations
Quality equipment to provide quality samples
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Injection & remediation services
Dedicated injection specialists can help with your design
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Sonic drilling services
We now offer sonic drilling services with automated rod handling
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Drilling services
Gregg Drilling is widely recognized as a leader and innovator in drilling, sampling, and subsurface investigation
Explore drilling services
Cone penetration testing services
We work to earn our clients’ trust and satisfaction by consistently responding to their needs with sound technical advice and innovative solutions
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Experienced personnel
All our personnel are highly trained, certified, and experienced in site investigation technologies and applications
Meet our team
Direct push Sampling
Soil and groundwater sampling services
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Full-service Remediation
Contact our remediation team to discuss the best options available
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Near-shore Site Investigations
With our dedicated drill ship, Quin Delta R/V
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Over-water Drilling & Testing
Experienced drillers can handle the difficulties with water-based investigations
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Delivering high quality environmental, geotechnical and marine drilling & testing solutions for over thirty five years.

Innovative solutions. Sound technical advice.

Workers in hard hats examining blueprints

Our commitment to responsive, reliable and cost effective service means solutions, savings and peace of mind to you and your organization.

Gregg Drilling, LLC is directed and staffed by geotechnical and environmental professionals with experience in industry, consulting, and research. All our personnel are highly trained, certified, and experienced in site investigation technologies and applications.

These exceptional qualifications enable Gregg personnel to solve complex problems and create a seamless working relationship between our staff and our clients.


Quality isn't something we test for after the job is done.
It's a way of doing business.

Keep up with the latest news

The services we offer, equipment & technologies we utilize, and project experience.

We want to hear from you

Please use the form below to e-mail us with any questions or project opportunities you may have. We will have the appropriate project manager return your request by the next business day. We hope to work with you soon.

Our offices

We have two convenient locations. Open M-F 7AM to 5PM

950 Howe Road
Martinez, California 94553
Job Related Questions & Cancellations: Jake Wilson
Cost Estimates & Other Questions: Tim Boyd
2726 Walnut Avenue
Signal Hill, California 90755
Cost Estimates, Scheduling & Cancellations: Joanna McKeehan