Underground storage tanks, or USTs, are have at least 10 percent of their volume beneath the ground’s surface.

They’re typically constructed of either steel or aluminum, composite materials (i.e., fiberglass, carbon fiber) or a composite-metal hybrid.

The typical volume of a UST varies upon the application, ranginge from a few hundred gallons to 500,000+ gallons. By way of example, the average corner gas station might have 3-4 10,000 gallon USTs underneath the concrete where drivers fill up their cars, one each for regular unleaded, mid-grade, premium and perhaps diesel.  

While still in use, USTs aren’t as common as they were in the past.  This is primarily due to leakage issues from corrosion and the associated liability from the resulting pollution. 

Today, USTs are strictly regulated to prevent the release of petroleum and other harmful contaminants. The right professionals are imperative to the design, construction, and operation/maintenance of USTs.


ASTs, or aboveground storage tanks, are similar to USTs in that they’re often constructed from metal, plastic, composite materials – or some combination of all three.

The primary difference, as the name implies, is that ASTs are located completely above the ground surface.

These tanks are more common than USTs, however like USTs, they must be designed according to the particular application as well as other factors such as resistance to fire/explosion, safety barriers for vehicular traffic, etc.  A typical AST for a commercial or municipal fueling operation might be a 10,000 gallon vaulted tank surrounded by a protective concrete covering. The average residential AST is a 275 gallon oval shaped steel vessel for heating purposes.

Expert UST & AST Services

At TEC, we specialize in taking USTs and ASTs from concept to reality, helping you with everything from installation to removal/abandonment to repair/replacement and the construction management that accompanies it.

TEC’s UST & AST Capabilities Include:

More Detail About our UST & AST Services

UST/AST Compliance Inspections

Local and federal laws require regular inspections of both underground storage tanks (USTs) and above ground storage tanks (ASTs). TEC can customize inspection plans as needed and store all data electronically.

UST compliance inspections are generally intended to detect fuel leaks before they occur. In addition to the tank itself, these inspections cover specific equipment such as cathodic protection equipment, alarms and sumps. AST compliance inspections assess the overall condition of the containment structure, including components such as dispenser pans, hoses, nozzles, spill containers and vents.

UST/AST Maintenance

TEC also repairs USTs and ASTs when inspections determine them to be faulty. Our team of trained professionals is qualified to perform any procedures needed to get these tanks back into compliance.

Some of the most common repairs include replacing a hose or breakaway, while troubleshooting and repairing an electrical problem can be a more challenging procedure. We also install fuel tanks when repair isn’t possible or practical, including the removal and closure of out-of-service tanks.