EPA Underground Storage Tank (UST) Regulations

There are approximately half a million federally regulated underground storage tanks across the United States — buried tanks holding petroleum products and hazardous substances at gas stations, airports, farms, and industrial facilities. When a tank leaks, the results can be severe: petroleum and chemical contamination of soil and groundwater that can migrate to drinking water supplies, sometimes years after a release begins. The EPA Underground Storage Tank (UST) program, operating under Subtitle I of the Resource Conservation and Recovery Act (RCRA), establishes the technical standards, release detection requirements, corrective action procedures, and financial responsibility rules that govern these tanks — with most day-to-day enforcement handled by state-run programs that EPA has approved.

The UST program has been a substantial environmental success: EPA estimates that proper installation and operation requirements have prevented hundreds of thousands of releases, while the corrective action framework has addressed contamination at hundreds of thousands of sites over the past four decades. But the work isn't finished — the agency estimates tens of thousands of leaking UST sites remain with open corrective action.

Current Rule (2026)

What This Rule Does

Part 280 regulates underground storage tanks that hold petroleum or certain hazardous substances. A UST system includes the tank itself plus underground piping, pumps, and ancillary equipment connected to it. Most regulated USTs store gasoline, diesel, and other petroleum products at gas stations and fleet facilities; the regulations also cover USTs holding hazardous substances defined under CERCLA.

Who is regulated. The rule applies to every owner and operator of a regulated UST system. Owners include whoever holds title or has a registered interest in the tank. Operators include whoever has daily control over the UST system's operations. Gas station franchisees, commercial fuel storage operators, airports, school districts with fuel storage, and industrial facilities are all common regulated parties. Several categories are excluded: farm or residential tanks of 1,100 gallons or less storing motor fuel; tanks storing heating oil used on-site; septic tanks and surface impoundments; flow-through process tanks; and most emergency spill containment structures.

The program structure. EPA sets the national minimum standards, but most regulated USTs are overseen by state implementing agencies — state environmental agencies with EPA-approved programs. When EPA has approved a state's program, state regulators (not EPA) are the "implementing agency" for that state's USTs, handling permits, inspections, corrective action oversight, and enforcement. All states and territories now have EPA-approved or -delegated programs.

Key Provisions

• § 280.20 — Performance standards for new UST systems: new tanks must use corrosion-protected materials (fiberglass, protected steel, or cathodically protected steel); piping must be protected against corrosion and equipped with spill and overfill prevention equipment; secondary containment is required for new tanks installed in certain settings
• § 280.21 — Upgrading existing systems: tanks that cannot meet technical standards must be permanently closed; the 2015 rule required all existing tanks to have secondary containment, spill prevention, overfill prevention, and corrosion protection by specific deadlines
• § 280.30 — Spill and overfill control: owners/operators must ensure releases due to spilling (from overfills during delivery) and overfill (tank capacity exceeded) are prevented; spill buckets must contain at least 5 gallons; overfill protection (automatic shutoff or flow restrictor) is required on all tanks
• § 280.31 — Corrosion protection: all metal USTs must be protected from corrosion through cathodic protection, interior lining, or a combination; cathodic protection systems must be tested within 6 months of installation and every 3 years thereafter; impressed current systems require annual operating checks
• § 280.35–280.36 — Periodic testing and walkthrough inspections: spill prevention equipment must be tested at least every 3 years; containment sumps used for interstitial monitoring must be tested at least every 3 years; operators must conduct annual and every-30-day walkthrough inspections to check for proper operation and visible damage
• § 280.40–280.44 — Release detection: every UST must have a method of detecting releases from the tank and piping; acceptable methods include automatic tank gauging, interstitial monitoring (the most reliable, using secondary containment space between inner and outer tank walls), statistical inventory reconciliation, vapor monitoring, and groundwater monitoring; manual tank gauging is only allowed for tanks of 2,000 gallons or less; piping release detection requires pressurized or suction line monitoring; records of all release detection must be kept for one year
• §§ 280.50–280.53 — Release reporting: suspected releases must be reported to the implementing agency within 24 hours; spills of more than 25 gallons or causing a sheen on nearby water must be cleaned up and reported; all confirmed releases must be reported within 24 hours
• §§ 280.60–280.67 — Corrective action: after a confirmed release, owners/operators must take initial response (remove product from tank, mitigate fire/safety hazard), perform initial abatement (remove free product, investigate source), characterize the site, remove free petroleum floating on groundwater, and submit a corrective action plan; the state implementing agency reviews and approves corrective action plans; public participation is required for corrective action plans affecting drinking water sources
• § 280.93 — Financial responsibility: owners/operators must demonstrate ability to pay for cleanup and third-party damages; minimum coverage is $1 million per occurrence (for petroleum USTs at facilities with 1–99 tanks) or $2 million per occurrence (for petroleum marketers with 100+ tanks); total annual aggregate coverage is $1–2 million; financial responsibility may be demonstrated through insurance, state funds, trust funds, surety bonds, letters of credit, or self-insurance through a corporate financial test
• §§ 280.240–280.245 — Operator training: all UST facilities must have designated Class A operators (management oversight), Class B operators (on-site operations and maintenance), and Class C operators (station employees who activate emergency response); Class A and B operators must complete state-approved training; retraining is required after significant violations

How It Affects You

If you own or operate a gas station or fuel storage facility: Your state's UST program — not EPA directly — is the agency you deal with for permits, inspections, and corrective action. Look up your state's UST program agency through EPA's state program directory at epa.gov/ust. Core compliance calendar: spill bucket inspection at every delivery; annual walkthrough inspection of all equipment; every-30-day walkthrough of containment sumps; release detection system checks per method requirements; cathodic protection testing every 3 years; spill prevention equipment testing every 3 years. Keep records of all inspections, tests, and release detection readings — you need 1-3 years of records on-site for state inspection. If you discover or suspect a release, call your state UST program immediately — 24-hour reporting is a hard requirement, and delays worsen both the environmental damage and your legal exposure.

Financial responsibility is a separate compliance obligation from the technical standards. You must document annually that you have $1 million or more in coverage for cleanup and third-party claims. Most small operators use their state's UST assurance fund (available in most states) or petroleum liability insurance. Make sure your insurance policy specifically covers UST corrective action costs — general commercial liability policies often exclude underground pollution.

If you're buying or selling property with a UST: Current or former UST presence is a significant due diligence issue. Request all UST registration records, release history, corrective action files, and state inspection reports from the seller and from the state implementing agency. Even a properly closed UST may have had an undetected historical release that left residual contamination. A Phase I environmental site assessment (ASTM E1527-21) is the standard for identifying UST-related recognized environmental conditions; a Phase II with soil and groundwater sampling may be needed if history or Phase I raises concerns. As a purchaser, you can become liable for corrective action costs under RCRA and potentially CERCLA even if the release predates your ownership — understanding the full UST history before closing is essential.

If you're a Class A or B operator due for training: EPA's operator training requirements have been in effect since 2018; all UST owners/operators were required to have trained operators by October 2018. If you've had a significant compliance violation since then, your Class A and B operators must complete retraining. Check your state UST program for approved training providers — many offer online courses. Undesignated or untrained operators are a common inspection finding that carries significant civil penalties.

Statutory Authority

This rule implements:

• 42 U.S.C. § 6912 — EPA authority under RCRA to prescribe regulations necessary to carry out the purposes of RCRA, including Subtitle I (Underground Storage Tanks), which Congress added to RCRA in 1984 to address the growing problem of UST releases contaminating drinking water supplies

Recent Rulemakings

• 80 FR 41566 (July 15, 2015) — Major update to Part 280 technical standards; added secondary containment requirements for new and replaced tanks and piping; added operator training requirements (Class A, B, C); strengthened release detection requirements; added walkthrough inspection requirements; phased in new requirements for existing tanks through 2018 deadlines
• No major Part 280 amendments 2020–2026 — the 2015 rule remains the current baseline; EPA has issued guidance on implementing the 2015 amendments and on compliance with operator training requirements

Recent Developments

• 2015 rule phase-in complete: The 2015 Part 280 update (80 FR 41566) required secondary containment for new and replaced UST systems and piping, and phased in operator training requirements (Class A, B, C) with deadlines extending through 2018. By 2020, the upgrade cycle was substantially complete. As of 2025–2026, most of the compliance focus is on maintaining newly-required equipment (sumps, interstitial monitoring systems) rather than new installation.
• PFAS contamination from UST leaks: Per- and polyfluoroalkyl substances (PFAS) contamination has emerged as a complication in UST release remediation. Some legacy fuel additives and firefighting foams used at fuel storage sites introduced PFAS to groundwater. While PFAS remediation is governed by CERCLA/RCRA cleanup standards rather than Part 280 directly, UST release investigations now routinely include PFAS sampling alongside traditional fuel contaminants (benzene, toluene, MTBE). EPA's 2024 PFAS MCL rule for drinking water creates new urgency for PFAS-contaminated UST sites near public water supplies.
• EV infrastructure and UST program overlap: The transition away from gasoline vehicles raises questions about the long-term future of the UST regulatory program. Federal EV charging infrastructure investment (NEVI program, IRA incentives) is driving gasoline station closings and tank removals, which trigger Part 280 closure and removal requirements. EPA and states are processing increased UST closure permits as fuel retailers anticipate reduced gasoline demand and close older facilities.
• State UST program delegation: Most UST program enforcement operates through state agencies that have received EPA approval to operate their own UST programs in lieu of federal enforcement. State program quality varies; EPA oversight reviews assess whether state programs maintain equivalence with federal Part 280 standards. States with large numbers of active USTs (California, Texas, Florida) account for a disproportionate share of confirmed releases and cleanup activity.

Pending Action

No comprehensive Part 280 rulemaking is currently pending. EPA's regulatory focus is on three near-term areas: (1) developing guidance on PFAS sampling at UST release sites following the April 2024 PFAS drinking water MCL rule, which creates new remediation urgency for UST sites near public water systems; (2) updating closure and removal requirements for UST sites associated with gasoline stations closing amid the EV transition; and (3) periodic state program oversight reviews to ensure EPA-approved state programs maintain equivalence with the federal standard. UST owners and operators with confirmed releases near public water supplies should consult EPA and state agency guidance on PFAS sampling requirements, which may apply even to sites in active BTEX remediation programs.