USTs are primarily used for the storage of petroleum products. They are found at service stations, connected to boilers/steam generators, or connected to emergency generators.
Summary of Federal Requirements
It is important to remember that a tank is a UST if 10 percent or more of the tank (including the volume of underground pipes connected to the tank) is underground. It does not have to be completely underground. Also, not every tank that is "underground" is Federally regulated. Under federal regulations an UST is any one or a combination of tanks (including underground pipes connected thereto) that is used to contain an accumulation of regulated substances, and the volume of which (including the volume of underground pipes connected thereto) is 10 percent or more beneath the surface of the ground.
This page is not intended to provide guidance on all aspects of the UST regulations. Its intent is to highlight changing requirements/new deadlines from 15 July 2015 publication of the revised 40 CFR 280.
EPA has also published the following aids about this revised rule and its implementation:
What Is and Is Not Federally Regulated
Under Federal regulation, the term "underground storage tank" does not include any of the following tanks (40 CFR 280.12):
- farm or residential tank of 1100 gal or less capacity used for storing motor fuel for noncommercial purposes
- tank used for storing heating oil for consumptive use on the premises where stored
- septic tanks
- pipeline facility (including gathering lines):
a. Which is regulated under 49 U.S.C. chapter 601; or
b. Which is an intrastate pipeline facility regulated under state laws as provided in 49 U.S.C. chapter 601, and which is determined by the Secretary of Transportation to be connected to a pipeline, or to be operated or intended to be capable of operating at pipeline pressure or as an integral part of a pipeline;
- surface impoundment, pit, pond, or lagoon
- stormwater or waste water collection system
- flow-through process tank
- liquid trap or associated gathering lines directly related to oil or gas production and gathering operations
- storage tank situated in an underground area (such as a basement, cellar, mineworking, drift, shaft, or tunnel) if the storage tank is situated upon or above the surface of the floor.
(NOTE: The definition of UST does not include any pipes connected to any tank which is described in para (1) through (9) of this list.)
The following types of USTs are also completely excluded from being regulated under 40 CFR 280 (see 40 CFR 280.10(b)):
- any UST system holding hazardous wastes listed or identified under Subtitle C of the Solid Waste Disposal Act, or a mixture of such hazardous waste and other regulated substances
- any wastewater treatment tank system that is part of a wastewater treatment facility regulated under Section 402 or 307(b) of the Clean Water Act (CWA)
- equipment or machinery that contains regulated substances for operational purposes such as hydraulic lift tanks and electrical equipment tanks
- any UST system whose capacity is 110 gal or less
- any UST system that contains a de minimis concentration of regulated substance
- any emergency spill or overflow containment UST system that is expeditiously emptied after use.
The following types of USTs are considered partially excluded, they only have to meet the requirements in 40 CFR 280, Subparts A, F, H, and I. They are exempt from Subparts B, C, D, E, G, J, and K (see 40 CFR 280.10(c)):
- Wastewater treatment tank systems not covered in the definition of Excluded USTs;
- Aboveground storage tanks associated with:
a. Airport hydrant fuel distribution systems regulated under 40 CFR 280, Subpart K; and
b. UST systems with field constructed tanks regulated under 40 CFR 280, Subpart K;
- Any UST systems containing radioactive material that are regulated under the Atomic Energy Act of 1954 (42 U.S.C. 2011 and following); and
- Any UST system that is part of an emergency generator system at nuclear power generation facilities licensed by the Nuclear Regulatory Commission and subject to Nuclear Regulatory Commission requirements regarding design and quality criteria, including but not limited to 10 CFR 50.
Prior to the 15 July 2015 publication of the revised UST regulations, 40 CFR 280 also used the terminology "Deferred USTs." This terminology is no longer valid. Instead, the following previously deferred systems are now subject to requirements under 40 CFR 280:
- Airport Hydrant Fuel Distribution System - (also called airport hydrant system) an UST system which fuels aircraft and operates under high pressure with large diameter piping that typically terminates into one or more hydrants (fill stands). The airport hydrant system begins where fuel enters one or more tanks from an external source such as a pipeline, barge, rail car, or other motor fuel carrier (40 CFR 280.250)
- Field-constructed Tank - a tank constructed in the field. For example, a tank constructed of concrete that is poured in the field, or a steel or fiberglass tank primarily fabricated in the field is considered field-constructed (40 CFR 280.250).
Also now specifically regulated under 40 CFR 280 are USTs used for the storage of substances containing > 10 percent ethanol or substances containing > 20 percent biodiesel (40 CFR 280.32(b)).
13 October 2015 Deadline Requirements
UST systems that store fuel solely for use by emergency power generators installed after 13 October 2015 meet all applicable requirements of 40 CFR 280 at the time of installation.
For Federally regulated USTs, when overfill prevention is installed or replaced after 13 October 2015, no flow restrictors may be used to achieve compliance with overfill prevention equipment requirements.
Airport hydrant fuel distribution systems and UST systems with field constructed tanks installed on or before 13 October 2015 must meet the following 40 CFR 280 requirements by 13 October 2015:
11 April 2016 Deadline Requirements
- release reporting (40 CFR 280.50)
- response and investigation (40 CFR 280.51 and 280.52)
- closure (40 CFR 280.70 through 280.74)
- financial responsibility and notification
With some exceptions, Federally regulated USTs installed on or before 11 April 2016 must be monitored every 30 days using one of the following methods (40 CFR 280.41):
- automatic tank gauging
- vapor monitoring
- groundwater monitoring
- interstitial monitoring
- statistical inventory reconciliation
- other acceptable methods.
Federally regulated USTs installed after 11 April 2016 are monitored for releases at least every 30 days in accordance with 40 CFR 280.43(g) interstitial monitoring requirements (40 CFR 280.41).
After 11 April 2016, regulated USTs or piping installed or replaced must be secondarily contained and use interstitial monitoring. Secondary containment must be able to contain regulated substances leaked from the primary containment until they are detected and removed and prevent the release of regulated substances to the environment at any time during the operational life of the UST system. For cases where the piping is considered to be replaced, the entire piping run must be secondarily contained.
UST systems with new dispenser systems installed after 11 April 2016 must have under dispenser containment (40 CFR 280.20(f)) A "Dispenser" is defined as equipment located aboveground that dispenses regulated substances from the UST system. A "Dispenser System" is the dispenser and the equipment necessary to connect the dispenser to the underground storage tank system. Under-dispenser Containment or UDC is defined as containment underneath a dispenser system designed to prevent leaks from the dispenser and piping within or above the UDC from reaching soil or groundwater.) A dispenser system is considered new when both the dispenser and the equipment needed to connect the dispenser to the UST system are installed at an UST facility. The equipment necessary to connect the dispenser to the UST system includes check valves, shear valves, unburied risers or flexible connectors, or other transitional components that are underneath the dispenser and connect the dispenser to the underground piping.) The UDC must be liquid-tight on its sides, bottom, and at any penetrations. Additionally, the UDC must allow for visual inspection and access to the components in the containment system or it must be periodically monitored for leaks from the dispenser system.
Piping installed on or before 11 April 2016 that routinely contains a regulated substance must be monitored for releases in a manner that meets one of the following requirements (40 CFR 280.41):
- pressurized piping:
- be equipped with automatic line leak detector
- annual tightness testing or monthly monitoring.
- suction piping: line tightness testing every 3 yr or acceptable monthly monitoring.
Piping installed or replaced after 11 April 2016 must meet one of the following release detection requirements (40 CFR 280.41):
- pressurized piping is monitored for releases at least every 30 days in accordance with 40 CFR 280.43(g) and be equipped with an automatic line leak detector in accordance with 40 CFR 280.44(a)
- suction piping is monitored for releases at least every 30 days in accordance with 40 CFR 280.43(g).
13 October 2018 Deadline Requirements
By 13 October 2018 owners and operators of Federally regulated USTs must implement one of the following inspection processes to ensure their equipment is operating correctly:
- conduct a walkthrough inspection that, at a minimum, checks the following equipment as specified:
- every 30 days (Exception: spill prevention equipment at UST systems receiving deliveries at intervals greater than every 30 days may be checked prior to each delivery)
- annually check containment sumps
- annually check hand-held release detection equipment
- conduct operation and maintenance walkthrough inspections according to a standard code of practice developed by a nationally recognized association or independent laboratory that checks equipment.
- conduct operations and maintenance walkthrough inspections developed by the implementing agency.
For UST systems in use on or before 13 October 2015, the initial spill prevention equipment test, containment sump test and overfill prevention equipment inspection must be conducted not later than 13 October 2018 (40 CFR 280.35)
UST systems that store fuel solely for use by emergency power generators installed on or before 13 October 2015 meet the release detection requirements in 40 CFR 280.40 through 280.45 on or before 13 October 2018.
By 13 October 2018 owners and operators of all UST systems must provide a method, or combination of methods, of release detection that is operated and maintained, and electronic and mechanical components are tested for proper operation, in accordance with one of the following (40 CFR 280.40):
- manufacturer's instructions
- a code of practice developed by a nationally recognized association or independent testing laboratory
- requirements determined by the implementing agency to be no less protective of human health and the environment.
By 13 October 2018 , a test of the proper operation of the release detection must be performed at least annually and, at a minimum, cover the following components as applicable to the UST system (40 CFR 280.40):
- automatic tank gauge and other controllers
- probes and sensors
- automatic line leak detector:
- vacuum pumps and pressure gauges
- hand-held electronic sampling equipment associated with groundwater and vapor monitoring
By 13 October 2018 owners of airport hydrant fuel distribution systems and UST systems with field constructed tanks must submit a one-time notice to the implementing agency documenting the existence of these previously deferred tank(s).
By 13 October 2018 airport hydrant fuel distribution systems and UST systems with field constructed tanks which were installed on or before 13 October 2015 must meet the following 40 CFR 280 requirements:
- upgrading of UST systems or closure (40 CFR 280.21 and 280.70 through 280.74)
- general operating requirements (40 CFR 280.30 through 280.36)
- operator training (40 CFR 280.240 through 280.245).
By 13 October 2018 all airport hydrant fuel distribution systems and UST systems with field constructed tanks must meet release detection requirements based on the capacity of the tank/piping (40 CFR 280.252)
Hazardous Materials Storage in USTs
Depending on the type and amount of hazardous materials (i.e., gasoline, diesel fuel, other liquids) stored and/or used at the facility, EPA reporting requirements may apply. The regulatory impacts of hazardous materials being stored and/or used at facilities are outlined in the Laboratories -> Hazardous Materials Storage section of the Facility Regulatory Tour.
USTs in Indian County
EPA's report, dated August 2007, titled "Report to Congress on Implementing and Enforcing the Underground Storage Tank Program in Indian County" outlines a framework that can be used as a foundation for discussing the unique underground storage tank program implementation issues of different tribal governments and provides a consistent method whereby the EPA and each tribe can continue to cooperatively work on these issues in the future. Additionally, EPA has established a portal for information and guidance on UST programs in Indian country.
Summary of State Requirements
EPA and the States have been working together to develop guidelines for the implementation of the Underground Storage Tank Compliance Act. These guidelines describe the minimum requirements that a state's UST program must contain in order for a state to comply with statutory requirements for Subtitle I funding. These guidelines include definitions, requirements, and examples. A state may choose to develop more stringent requirements than described in these guidelines. The definitions from these guidelines can be found here.
States receiving Subtitle I funding must implement one of the following by 8 February 2007:
Option 1, Tank And Piping Secondary Containment:
NOTE: States are not required to apply the secondary containment requirements in the following situations:
- Each new or replaced underground tank, or replaced tank, that is within 1,000 feet of any existing community water system or any existing potable drinking water well must be secondarily contained and monitored for leaks.
- In the case of a replacement of an existing underground tank or existing piping connected to the underground tank, the secondary containment and monitoring applies only to the specific underground tank or piping being replaced, not to other underground tanks and connected pipes comprising such system.
- Each new motor fuel dispenser system installed within 1,000 ft of any existing community water system or any existing potable drinking water well must have under-dispenser containment. These requirements do not apply to repairs meant to restore an underground tank, pipe, or dispenser to operating condition.
Option 2, Evidence Of Financial Responsibility And Certification:
- A person that manufactures an underground tank or piping for an underground storage tank system or installs an underground storage tank system maintains evidence of financial responsibility under Section 9003(d) of Subtitle I in order to provide for the costs of corrective actions directly related to releases caused by improper manufacture or installation unless the person can demonstrate themselves to be already covered as an owner or operator of an underground storage tank under Section 9003 of Subtitle I.
- Underground Storage Tank installers must:
- Be certified or licensed (see below for certification details);
- Have the installation certified or approved;
- Install the underground storage tank system compliant with a code of practice and in accordance with the manufacturer's instructions; or use another method determined to be no less protective of human health and the environment.
Financial Responsibility and Installer Certification
- To underground tanks that are not new or replaced in a manifolded underground tank system.
- For underground tanks with multiple piping runs, to those piping runs that are not new or replaced.
- To suction piping that meets the requirements at 40 CFR 280.41(b)(2)(i) – (v) or to piping that manifolds two or more underground tanks together.
- When a new motor fuel dispenser system is installed at an existing underground storage tank facility and new piping is added to the underground storage tank system to connect the new dispenser to the existing system, the existing piping to which the new piping is connected does not have to meet these guidelines.
(NOTE: States receiving Subtitle I funding must implement either the financial responsibility and installer certification requirements or the secondary containment requirements.)
A person that manufactures an underground tank or piping for an underground storage tank system or installs an underground storage tank system must maintain evidence of financial responsibility under Section 9003(d) of RCRA, Subtitle I in order to provide for the costs of corrective actions directly related to releases caused by improper manufacture or installation unless the person can demonstrate themselves to be already covered as an owner or operator of an underground storage tank under Section 9003, Subtitle I.
In states where a single installer of an underground storage tank system is identified by the state (e.g., for purposes of obtaining a permit), that person is the one required to maintain financial responsibility for that installation and meet the certification requirements described in these guidelines. Where there is not a single installer on record, states must define those who must maintain evidence of financial responsibility and meet the certification requirements described in these guidelines.
Underground storage tank installers must:
For installers, States must require a minimum of $1 million per occurrence and $2 million annual aggregate to cover the costs of corrective action of a release from a regulated underground storage tank system due to improper installation.
Installers of underground storage tank systems maintain financial responsibility for ten years after installation, or until the underground storage tank system is permanently closed.
Installers of underground storage tank systems must meet one of the following:
- be certified or licensed;
- have the installation certified or approved;
- install the underground storage tank system compliant with a code of practice and in accordance with the manufacturer's instructions; or
- use another method determined to be no less protective of human health and the environment.
Delivery Prohibition Requirements
Underground storage tank owners/operators and product deliverers are responsible for not delivering, depositing, or accepting product to an underground storage tank identified by EPA or a state as ineligible to receive product. Tanks should be tagged as to whether they are ineligible or eligible (i.e., red tags or green tags).
A state must classify an underground storage tank as ineligible for delivery, deposit, or acceptance of product as soon as practicable after the state determines an underground storage tank meets one or more of the following conditions:
- Be certified or licensed by the tank and piping manufacturer;
- Be certified or licensed by the EPA Administrator or a state, as appropriate;
- Have their underground storage tank system installation certified by a registered professional engineer with education and experience in underground storage tank system installation;
- Have their installation of the underground storage tank inspected and approved by the Administrator or the state, as appropriate;
- Be compliant with a code of practice developed by a nationally-recognized association or independent testing laboratory and in accordance with the manufacturer's instructions; or
- Be compliant with another method that is determined by the Administrator or a state, as appropriate, to be no less protective of human health and the environment.
NOTE: These requirements are similar to the requirements already found under 40 CFR Parts 280.20(d), 280.20(e), and 280.33(a). Most, if not all, state underground storage tank regulations already cover these requirements for new installations and repairs. However, states must also require that persons who replace or add equipment after the initial installation of the underground storage tank system meet the installer certification requirements.
A state should also classify an underground storage tank as ineligible for delivery, deposit, or acceptance of product if the owner/operator of that tank has been issued a written warning or citation (notice of violation or other form indicating a violation) under any of the following circumstances and the owner/operator has failed to take corrective action after a reasonable time frame that is determined by the state:
- Required spill prevention equipment is not installed;
- Required overfill protection equipment is not installed;
- Required leak detection equipment is not installed;
- Required corrosion protection equipment is not installed;5 or
- Other conditions a state deems appropriate.
States may choose to prohibit delivery, deposit, or acceptance of product to an individual underground storage tank or to every underground storage tank at a facility. The state must develop criteria and time frames for prohibiting the delivery, deposit, and acceptance of product.
- Failure to properly operate and/or maintain leak detection equipment;
- Failure to properly operate and/or maintain spill, overfill, or corrosion protection equipment;
- Failure to maintain financial responsibility;
- Failure to protect a buried metal flexible connector from corrosion; or
- Other conditions a state deems appropriate.
Laws and Statutes
Resource Conservation and Recovery Act, Subtitle I
Underground Storage Tank Compliance Act (Title XV, Subtitle B of the Energy Policy Act of 2005)