Experienced. Dependable. Innovative.

Gregg Drilling is known as the site investigation provider our clients can depend on for quality work through experienced personnel, planning and innovative equipment.


“My name is Sarah Winn, I work for Kleinfelder, And I had the pleasure of working with one of your drill teams for this last project. I have to say they are the best drillers I have ever worked with. Not only were they fast and efficient, they were also safe, kind, hilarious and very clean. They took extra care to even sweep up tire marks so that property owners, who are forced to allow us on their land because of court orders, did not feel like we left a trace. Even the environmental biologists on site were impressed, with Christy at ESA taking photos to use as an example to other sites.”

“I wanted to let you know that Juan, Jose and Frank did an excellent job with the well abandonments at Miramar. I really appreciated their thoroughness and professionalism, they were great to work with!” – Joseph Plummer, Bay West

“John, I have never worked with a PM that worked so hard to maintain excellent communication with me, the contractor and your own crew to make sure everyone had what they needed, were on the same page and the job was a success. I couldn’t believe how smooth everything ran thanks to your efforts.” – Jason Miller, Rinconada Water Treatment Plant

“I have worked with many drilling crews over the years and can easily say this was the best team I have ever worked with.  The crew of Francisco, Jarred and Robert were absolutely incredible.  Besides the obvious strong work ethic, everyone who stopped by noticed they were always in the correct PPE at all times which made safety very happy.  Automatically without ever a word spoken they operated in a manner that made our environmental team extremely pleased with their visqueen placement, cleanliness and way the jobsite looked at all times.  With our local neighbors being notorious for noise complaints, this crew never started an engine before 8 and always had everything shut down right before 5 which brought high praise from our public outreach team.  My manager and many other district staff are calling this project a huge success and a major part of that is on the shoulders of this crew.  I look forward to working with all of you again soon.” – Jason Miller, Rinconada Water Treatment Plant

“I worked with Armando and Danny 11/9-11/11 and they are the best drill crew I have ever had. They were such a positive experience because they did the job per the county parameters without complaint, consistently wore the correct safety gear without being reminded, and always had a positive attitude even through the challenging work. Because of their hard work we got so much done, and I wanted to let you know how much we appreciate that. If possible, we would love to request them on the last part of the job from 11/29-12/2.” – Avery Knizek, Antea Group

“Just wanted to let you know that our field team had a really positive experience working with the crew out in Redwood City over the past two weeks. They specifically mentioned that Christian and Rodrigo were “very professional, worked their butts off, were great at communicating/listening/answering questions, and were just great guys to work with.” I would definitely request them again on future projects.

I’ve worked with Rodrigo several times over the last four years and definitely agree with this praise, and from the few times I’ve worked with Christian, I’m not surprised to hear this kind of feedback either. Thanks to you too for putting together such a great team and making it such an easy job out there.” – Nick Frederiksen, Sr. Staff Geologist, Geosyntec

“I wanted to also thank you for putting together the well organized and highly valuable Field Day on Saturday [March 11, 2023]. It was excellent! It was a great experience for our staff of varying experience levels, from entry level geologist to Principal level. I also really appreciated that Gregg included the gender diversity that does exist in this line of work.  Visibility is so important- for the new graduates especially, so it is always nice to hear and learn from experienced women in the industry.

Thanks again, and great job to all of you who helped plan and deliver the Field Day.” – Jamie Cachine, BSNC

“I just wanted to pass along how happy I was with Keith’s, and his team’s, performance on my project in Los Angeles last week. Access was the most difficult that I’ve encountered in my 30+ years of fieldwork, with fractions of an inch of space between the rig and walls/equipment during our drive and several overhead lines and objects. Keith was confident and his eyeball estimates and driving abilities were spot on. The property owner, who can be difficult to work with, loved Keith and his attitude. He made a tremendously tough job much less stressful, and he succeeded despite my estimate of us having < 30% chance of completing the scope. I’ve worked with Keith many times and never fail to appreciate his attitude and his professionalism, yet he outdid himself on this one.

I’ve always appreciated your support team but the drillers most of all. They’re the best in the business. I’ve drilled in 40 states and there’s no comparison.” – Jim Robert, Salem Engineering Group

AECOM has had the pleasure of working with Gregg Drilling and their overwater drilling capabilities with the Quin Delta in the past, and most recently in the Summer of 2023. Their knowledge of the region, overwater drilling expertise, and incredible staff have been a tremendous asset to many projects that AECOM has worked with Gregg on in the Sacramento Delta Region.   Some of the geotechnical exploration work with “The Quin Delta”  has required difficult navigation into shallow waters, but the Gregg Over-water team has done a great job in working through these difficult challenges.  We look forward to working with Gregg and “The Quin Delta” when duty calls in the future.” – David Pieczynski, AECOM

“I wanted to let you know that it was a real pleasure working with Jarred, Clay, and Armando. They were honestly the best drilling crew I have worked with in a long time (probably ever) and certainly the best crew I have worked with at Gregg.

They were friendly, hard-working, and competent – willing and able to answer all my and [our client’s] questions. They kept to the schedule and most importantly did so safely, amidst the chaos of downtown and all the other hurdles we had to jump over.” – Carolina Zamora, Shannon & Wilson

Industries Serviced

Over the past 37-years, Gregg Drilling has been involved in a wide range of projects for both geotechnical and environmental sectors. From initial geotechnical investigations through to instrumentation installation, Gregg has worked extensively across the Western US in construction and mining.

Our environmental services cover large superfund sites, refineries and military bases to small dry-cleaner sites. We install both large and small monitoring wells supporting the Department of Water Resources though to on-going sampling and monitoring at sites. We have grown our remediation division to support injection platforms and work closely with chemical vendors and our clients to help design the best solutions for  your site clean-up.

As part of Sealaska, we believe a better future, one in which both people and the planet thrive, is within reach.

Equipment Delivering Solutions

Since our inception, Gregg Drilling has been delivering high-quality environmental, geotechnical, and marine drilling and testing solutions to clients in California and world-wide. We pride ourselves in communicating our client’s goals to our field crews and ensuring we provide the best equipment solutions and personnel to complete the project, exceeding expectations.

Innovative solutions, sound technical advice drive results.

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

Through Sealaska’s ‘Woocheen’ group, Gregg Drilling is working together with other partner companies including Sealaska Marine Services, CS Marine Constructors and Causeway Geotech to solve our ocean health crisis.

Sealaska’s Hydro Sciences teams bring together expertise in geosciences, construction, data science and more to keep freshwater clean, heal our oceans and support harnessing offshore wind energy.