Leaking Gas Tanks Under Your Feet — EPA's UST Database

Data source: ZipCheckup analysis of EPA Underground Storage Tank (UST) and Leaking UST (LUST) data, cross-referenced with EJScreen proximity indicators

Under the parking lot of your neighborhood gas station, there are tanks. Steel or fiberglass, buried 4 to 8 feet underground, holding thousands of gallons of gasoline, diesel, or heating oil. When those tanks corrode — and they do — the fuel seeps into the soil and, eventually, into the groundwater you might be drinking.

The EPA tracks every one of these tanks. Every leak. Every cleanup. And ZipCheckup has mapped all of it to your ZIP code.

The Numbers

Across the United States, the EPA monitors 455,830 underground storage tanks. Of those, 43,801 have confirmed leaks that remain unresolved — open LUST (Leaking Underground Storage Tank) cases where contamination hasn't been fully cleaned up.

ZipCheckup's analysis of EJScreen data shows the geographic concentration of UST risk across 42,675 ZIP codes:

Over 17,600 ZIP codes — 41% of the country — have census tracts that exceed EPA's EJScreen threshold for UST proximity. That means nearly half of American ZIP codes have at least some elevated underground tank contamination risk.

The States With the Most Tanks

Texas leads the nation with 52,345 registered underground storage tanks and 2,876 open LUST cases. But California has a worse leak-to-tank ratio:

California has 38,215 tanks but 3,812 open leaks — the highest in the nation. Pennsylvania has fewer tanks (18,234) but 3,789 open leaks, nearly matching California's contamination burden.

Michigan stands out with 3,456 open LUST cases from only 14,567 tanks — a leak rate that suggests aging infrastructure and delayed cleanups.

The Highest-Risk ZIP Codes

EJScreen's UST proximity indicator measures how close residents live to underground storage tanks relative to the national distribution. ZIP codes in the 97.5th percentile have the most concentrated UST exposure in the country:

New Jersey dominates the very-high-risk list with 325 ZIP codes rated very high — more than any other state. New York follows with 321, and Washington, D.C. has 284 (nearly all its ZIP codes).

This makes geographic sense. Dense urban areas have more gas stations, commercial heating oil tanks, and legacy industrial sites packed into smaller footprints. A ZIP code in Newark, NJ (97.5th percentile) has far more buried tanks per square mile than a rural ZIP in Kansas.

What's Actually Leaking

Underground storage tanks don't leak water. They leak petroleum products — gasoline, diesel, heating oil — which contain some of the most harmful groundwater contaminants:

• Benzene — a known carcinogen, even at low concentrations
• Toluene — affects the nervous system
• Ethylbenzene — potential carcinogen
• Xylenes — can cause liver and kidney damage
• MTBE — makes water undrinkable at extremely low concentrations (taste and odor threshold: 20-40 ppb)

These compounds are collectively called BTEX. They dissolve readily in groundwater and can travel significant distances from the leak source. A single leaking gas station tank can contaminate a groundwater plume extending thousands of feet.

The Cleanup Backlog

The "closed LUST" numbers tell an important story about remediation pace. Nationally, far more sites have been cleaned up than remain open — but 43,801 open cases represents a massive backlog.

Some of these open cases have been on the books for decades. Cleanup depends on state funding, responsible party cooperation, and the complexity of the contamination. In many cases, the gas station that caused the leak no longer exists — the company closed, the property changed hands, and the contamination sits in legal limbo while benzene continues to migrate through the soil.

What This Means for Homeowners

If you're buying a house, UST proximity is one of the environmental factors that can affect:

• Property value — homes near active LUST sites can see 5-15% value reduction
• Water quality — especially if you're on a private well (no EPA monitoring)
• Mortgage and insurance — some lenders require Phase I environmental assessments near known contamination
• Future liability — in some states, property owners can be held responsible for contamination they didn't cause

Check Your ZIP

ZipCheckup combines EPA UST/LUST data with EJScreen environmental justice indicators, water quality records, lead risk data, and dozens of other factors. Every data point is sourced from federal agencies.

Check your ZIP code on ZipCheckup