Specialty · Insurance Term
Underground Storage Tank (UST)
Definition
An underground storage tank (UST) is a tank system, including connected underground piping, with at least 10% of its volume below ground, used to store regulated substances like gasoline or diesel. Gas stations rely on them, and federal and Texas rules require registration, leak detection and proof of financial responsibility.
In Plain English
The federal definition in 40 CFR 280.12 counts the tank and connected underground piping. It excludes some tanks, such as small farm or residential motor fuel tanks and heating oil tanks used on the premises.
Tank owners must meet operating rules and financial assurance requirements, usually through storage tank liability insurance. General liability policies often exclude leaks through a pollution exclusion.
Leaks can contaminate soil and groundwater on your site and neighbors' sites. Cleanup can take years, so older tanks and their records are a major focus for buyers, lenders and insurers.
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Example
Hypothetical: a buyer is purchasing a convenience store with three 20-year-old fiberglass tanks. The buyer orders an environmental assessment, reviews TCEQ records, and arranges a new tank liability policy effective at closing.
Why It Matters for Texas Property Owners
The Texas Commission on Environmental Quality administers UST rules in Texas, including registration and financial assurance. Tank age, registration status and any past releases are common questions in Texas gas station purchases.
What to Watch For
- Keep tank registration, testing and leak detection records organized.
- Know your tanks' age, materials and any past releases.
- Confirm tank liability limits meet federal and TCEQ minimums.
- Ask whether your tank policy covers both cleanup and third-party claims.
Common Questions
Does my property insurance cover a tank leak?
Usually not. Property and general liability policies commonly exclude pollution, so tank owners rely on a separate storage tank liability policy.
Do aboveground tanks follow the same rules?
No. Aboveground tanks have different rules, though they may still create pollution risks that need coverage.
Sources
- 40 CFR 280.12 (definitions)
- 40 CFR 280.93
- TCEQ: Financial Assurance for Petroleum Storage Tank Systems
Last updated October 14, 2026 · Primesure editorial team · How We Write