---
title: "What Is UST (Underground Storage Tank)? | Calibre Glossary"
description: "An underground storage tank system is a tank and connected underground piping with at least 10 percent of its combined volume underground, regulated."
url: https://calibre.multisites.ai/glossary/underground-storage-tank
publisher: Calibre Commercial Inspections
phone: "+1-208-305-6245"
email: Schedule@CalibreCBI.com
---

Environmental

# Underground Storage Tank (UST)

An underground storage tank system is a tank and connected underground piping with at least 10 percent of its combined volume underground, regulated federally when it stores petroleum or certain hazardous substances.

## Why it matters

Old fuel tanks at gas stations, fleet yards and industrial sites are common sources of soil and groundwater contamination. Finding one can raise a recognized environmental condition. Removal and closure records matter to buyers and lenders.

Source: [epa.gov](https://www.epa.gov/ust/learn-about-underground-storage-tanks)

[Related Calibre servicePhase I Environmental Site Assessments](https://calibre.multisites.ai/cre-services/esa-environmental-site-assessments)

## Where we discuss it

-   [Phase I ESAs in the Inland Northwest: Which State Records Get Searched](https://calibre.multisites.ai/cre-inspector-insights/phase-1-esa-state-records-inland-northwest)

## Ready for your next inspection?

Tell us about the property and your timeline. We will scope the right report and send a proposal.

[Request a proposal](https://calibre.multisites.ai/request-proposal) [(208) 305-6245](tel:+12083056245)