We’re a small, experienced team offering hands-on field support for environmental consultants and engineers across Southern California. Whether it’s soil testing before a construction project or remediation during a cleanup, we show up on time, ready, and with the right tools.

For over 20 years, DEFS has been the go-to partner for accurate pilot testing, dependable soil gas sampling, and trusted field solutions. We don't just send techs  we work as part of your team.

Our Core Services

Soil Testing

Before any environmental decision is made, solid data is key. We collect and log samples efficiently to help you move forward confidently with investigations, cleanups, and compliance reports.

Remediation Fieldwork

We assist on-site with remediation system support, including system monitoring, maintenance, and sampling. Our team follows protocols, meets deadlines, and communicates clearly.

Pilot Testing

Need real-world system performance data? We help set up and execute pilot tests, manage flow rates, track emissions, and record everything you need for design-phase decisions.

Soil Gas Sampling

We handle soil gas sampling projects from small-scale sites to full commercial investigations. You can count on consistent data and proper QA/QC every time.

Why Environmental Pros Choose Us

• Based in Southern California, serving local counties with ease

• Over two decades of field experience

• Fully trained, safety-conscious technicians

• Flexible scheduling & rapid deployment

• Reliable communication & transparent reporting

Let’s Work Together

Whether you need same-week sampling or long-term field support, DEFS is ready to help. Reach out today and let’s talk about how we can support your next project.