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CTS’s Sioux City location has moved!

The new Sioux City office is located at 1400 US Highway 75  Sioux City , IA 51105.

Our mailing address will remain at P.O. Box 1193, Sioux City, IA 51102.

Geotechnical Engineering

Construction Materials Testing

Your Partner in Precision and Promptness: Certified Testing Services, Inc.

At Certified Testing Services, Inc., we pride ourselves on being more than just a service provider; we're your partners in ensuring quality and reliability. With 36 years of rich experience under our belt, our journey has been one of dedication, skill, and unwavering commitment to our clients. Our client-centric approach is the cornerstone of our business, guiding every interaction and service we provide.

Why Choose Certified Testing Services, Inc.?

Fast, Accurate, and Reliable Results

Trusted Professionals

Locally Owned and Operated

Certified Laboratory

IOWA DOT

Nebraska DOT

Army Corps of Engineers

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Valued Client Care

The Base of a Strong Foundation Starts Here!

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A group of construction workers are working on a concrete floor
A group of construction workers are working on a concrete floor