40 CFR 280: EPA Underground Storage Tanks

Regulatory citation: Resource Conservation and Recovery Act, Subtitle I; 40 CFR Part 280, Underground Storage Tanks

What Are EPA's Underground Storage Tank Rules?

40 CFR Part 280 sets technical standards for underground storage tank (UST) systems that store petroleum or certain hazardous substances. A tank system is generally a UST if 10% or more of its volume, including underground piping, is beneath the ground. EPA strengthened the rules in 2015, adding operator training and more frequent inspection and testing.

Why UST Rules Matter

Leaking USTs are a major source of groundwater contamination, which can affect drinking water supplies and create fire and vapor hazards. Common UST owners include gas stations, fleet facilities, utilities and government agencies.

Core Requirements

1. Know What's Covered

Exclusions include farm and residential tanks of 1,100 gallons or less storing motor fuel for noncommercial purposes, and tanks storing heating oil used on the premises. Some excluded tanks may still be regulated by states.

2. Corrosion Protection

Tanks and piping in contact with the ground must be protected from corrosion, for example by using noncorrodible materials or cathodic protection that is tested regularly.

3. Spill and Overfill Prevention

UST systems must have spill and overfill prevention equipment. Spill prevention equipment must generally be tested every three years, and overfill prevention equipment inspected every three years.

4. Release Detection

Owners and operators must use release detection methods for tanks and piping, such as automatic tank gauging, interstitial monitoring or statistical inventory reconciliation, and keep monitoring records.

5. Walkthrough Inspections

Walkthrough inspections must be done at least every 30 days, covering spill prevention equipment and release detection, with additional annual checks of containment sumps and handheld release detection equipment.

6. Operator Training

Facilities must designate trained Class A, Class B and Class C operators, who are responsible for overall compliance, day-to-day operation and initial response to emergencies.

7. Release Reporting and Closure

Suspected and confirmed releases must be reported to the implementing agency, generally within 24 hours. Owners must notify the agency before permanently closing a tank, usually 30 days in advance, and assess the site for contamination.

Common Compliance Approaches

Compliance Calendar

Track 30-day, annual and three-year inspection and testing deadlines for every tank in one calendar.

Respond to Alarms Promptly

Train Class C operators to respond to release detection alarms and spills, and escalate quickly.

Check State Program Rules

Most states run approved UST programs, often with additional requirements such as registration fees and state-specific inspections.

Example: UST Compliance in Practice

A city fleet garage has two 10,000-gallon fuel USTs. The fleet manager is the designated Class A and B operator, and fueling attendants are trained as Class C operators. The automatic tank gauge runs monthly leak tests, staff complete documented 30-day walkthroughs, and a contractor tests the spill buckets every three years. When the tank gauge triggers a leak alarm, the operator investigates, finds a failed sensor rather than a leak and documents the result for the state agency.

Related regulations: EPA SPCC Rule, EPA release reporting, EPA Industrial Stormwater.

Note: This summary reflects federal EPA requirements. Many states run authorized programs with additional or stricter rules. Always check the current regulation text and your state environmental agency's requirements.

Frequently Asked Questions

What counts as an underground storage tank?

A UST is a tank system, including connected underground piping, that has 10% or more of its combined volume underground and stores a regulated substance such as petroleum. Some tanks are excluded, such as small farm or residential motor fuel tanks and heating oil tanks used on site.

How often must UST walkthrough inspections be done?

Walkthrough inspections must be done at least every 30 days, with additional checks of containment sumps and handheld release detection equipment at least annually, unless the implementing agency approves a different schedule.

What are Class A, B and C UST operators?

Class A operators have primary responsibility for operating and maintaining the UST system and broad compliance knowledge. Class B operators handle day-to-day implementation of requirements. Class C operators respond to alarms and emergencies, and are usually on-site staff such as attendants.