Underground Storage Tanks and Compliance

Our Underground Storage Tank (UST) Program enforces the North Carolina Administrative Code Title 15A Subchapters 2N and 2L. Our staff enforces the UST regulations of North Carolina through a memorandum with NC Department of Natural Resources (DENR), Waste Management Division. We determine who is the responsible party for environmental contamination, conduct leak detection compliance inspections, and oversee tank removal, assessment, and remediation.

Underground Storage Tank (UST) systems are regulated by the North Carolina Department of Environment and Natural Resources. The 2N rules establish criteria and standards applicable to regulated USTs and include the requirements and procedures for permanently closing UST systems. The 2N rules do not apply to unregulated USTs. However, when a release from a unregulated UST is discovered or confirmed, the responsible party (tank owner) needs to comply with 15A NCAC 2L .0115 for the assessment and remediation.

Regulated vs. Unregulated USTs

Regulated
Unregulated
  • Any UST containing regulated substances, as defined in 15A NCAC 2N, specially petroleum (including but not limited to gasoline, diesel, and used/waste oil) or a hazardous substance (including halogenated or non-halogenated solvents).
  • Farm and residential tanks <1,100 gallons of motor fuel used for non-commercial purposes
  • Tanks storing heating oil used on premises where stored
  • Tanks on or above the floor of an underground area
  • Septic tank
  • Storm water or wastewater collection systems
  • Tanks <110 gallons
  • Emergency spill and overfill tanks
  • Field construction tanks
  • Flow through tanks
  • Operational tanks (hydraulic lifts etc.)

Leaking Petroleum UST Cleanup Fund

A State Trust Fund is available for the cleanup of leaking petroleum USTs. The commercial fund covers regulated USTs and those unregulated USTs required to be registered, permitted, and to pay annual operating fees. The Non-Commercial Trust Fund has been phased out by Session Law 2015-241 Section 14.16A.

Commercial USTs vs. Non-commercial USTs

Commercial USTs

Non-commercial USTs

  • Commercial motor fuel USTs
  • USTs for heating oil >1,100 gallons such as used by: churches, hospitals, schools, colleges, orphanages, factories, commercial centers, etc.
  • USTs for petroleum fuel used at golf courses etc., even if< or = 1,100 gallons
  • Farm or residential USTs >1,100 gallons
  • Farm or residential USTs < or = 1,100 gallons of motor fuel for non-commercial purposes
  • USTs < or = 1,100 gallons of heating oil for consumptive use on premises where stored
  • USTs >1,100 gallons of heating oil for consumptive use by four or fewer households

If you have any questions about the Trust Fund, please contact Guilford County Environmental Health at 336-641-3771, Winston-Salem Regional Office at 336-776-9800, or UST Section Central Office Trust Fund Branch at 919-707-8600.

Notification Requirements

  • Following a known or suspected release from an underground storage tank (UST) system, the responsible party (tank owner or operator) is required to submit a 24-Hour Release and UST Leak Reporting Form within 24 hours of discovery of a known or suspected release to the Winston-Salem Regional Office UST Section or Guilford County Environmental Health.
  • Prior to removing a regulated UST, the tank owner or operator must complete and submit a GW/UST-3 Form (UST Permanent Closure of Change-in-Service) at least five (5) working days if a Professional Engineer (P.E.) or a Licensed Geologist (L.G.) provides supervision for closure assessment activities and signs and seals all closure reports. Otherwise, 30 days' notice is required.

Regulatory Procedures for Regulated USTs

Please refer to the UST Section’s Guidelines for Assessment and Corrective Action.

  • Within 30 days after closure has been completed, a UST closure report following the UST-12 Format, and a UST-2 Form (Site Investigation Report for Permanent Closure or Change-in-Service of USTs), must be completed and submitted to the regional office. A copy of UST-2 Form needs to be submitted to the UST Section Central Office to change the UST status.
  • Once evidence of a petroleum release is discovered, the responsible party must take immediate action to prevent any further release of product from the UST and identify and mitigate any fire, explosion or vapor hazards, remove free product, and comply with the 2N requirements.
  • If the responsible party cannot demonstrate that soil contamination has been cleaned up, a limited site assessment report (LSA) must be submitted within 120 days of the discovery of the release. The LSA report must include the information needed by the DENR to assign a land use classification and to determine the risk level for the incident.
  • After determining the risk level of the site, the DENR will notify the responsible party about the requirements for assessment and remediation.

Before installing any monitoring/remediation wells at the site, a permit must be obtained from Guilford County Health Department.  The well installation application can be downloaded for your use.

UST for Home Heating Oil

Home heating oil tanks are those tanks defined as unregulated, non-commercial USTs above.  A list of frequently asked questions has been compiled for your information about heating oil tanks.

UST Compliance

USTs registered with NC Department of Environment and Natural Resources are required to be inspected by Division of Waste Management UST Section. The goal of the compliance inspections is to protect humans and the environment from release from UST’s. The regulations require owners and operators to prevent releases, detect releases, and correct problems caused by releases. An inspection of your UST system and a review of your records will find and help you correct and deficiencies to ensure that human health and the environment are protected and to fulfill the state and EPA requirements. Owners and operators are equally responsible for complying with all applicable UST regulations. Compliance inspections for the past 12 months in North Carolina indicated less than half the facilities inspected are in compliance.

A UST system consists of the underground storage tank, all associated piping and ancillary equipment (e.g. flex connectors, submersible pumps, pipe joints, etc.), and the dispenser (gas pump). Tank owners are required to pay tank fees for their registered tanks even if the tanks are in temporary closure. The fees are part of the owner’s financial responsibility requirements in case of a leak from the system.

Information and current status for any active UST systems installed in Guilford County can be obtained by visiting Guilford County GIS web site.

Additional Information

Tab/Accordion Items

NC General Statute requires a UST facility to have a current operating permit to receive fuel deliveries. If a facility does not have a current permit then a fuel deliverer cannot deliver any fuel to the UST system.  A facility will not be issued a operating permit for following reasons: incorrect mailing address, failure to pay tank fees, improper completion of the forms, insufficient proof of ownership, insufficient proof of financial responsibility, and/or compliance violation.

All regulated UST systems are required to have overfill devices to ensure that petroleum or hazardous material are not released to the environment while filling USTs. The overfill protection includes a flapper valve, a overfill alarm, and a ball float valve. The flapper valve will shut off filling operation at 95% of the USTs capacity. The overfill alarm works in conjunction with automatic gauge system to provide a visual and audible alarm when the tank reaches 90% of the UST’s capacity or within one (1) minute of being overfilled. The ball valve is installed at the tanks vent pipe to restrict the UST's vapor flow. It works on the principle that as the tank fills, the ball in the valve rises to restrict vapor flow. Once activated it will slow the product delivery by increasing the vapor pressure in the tank. 

The fill port of each UST system must have a spill bucket free of holes or defects, and free of water, fuel, and debris. It should be clean and dry at all times. The spill bucket is not made to hold product for extended period of time. If there are holes in the bucket, the UST system has a release to the environment.

The UST’s piping system is either pressurized or suction piping. Release from piping systems is one of primary sources of contamination from UST system. Pressurized piping must have an automatic line detector capable of detecting a release of 3 gallons per hour. If the leak detector is mechanical, it must be tested annually. If the detector is electronic, it must also be tested annually unless the manufacturer states the unit performs an automatic functional self-test. Suction piping for some new systems has only one (1) check valve under the dispenser pump (also known as safe suction or European suction). While most check valves are readily visible, those encased in a union may not be. If there is a check valve under the dispenser, and no other check valve in the line, no additional leak detection is required if the piping operates at less than atmospheric pressure and is sloped so the pipe contents drain into the tank when suction is released. 

UST systems are required to be sited at certain distance from wells and specified surface waters.

  • No regulated UST system (including tank, piping and dispensers) may be installed within 100 feet of the public water supply well. Regulated UST systems may be installed between 100 and 500 feet of public water supply well, but secondary containment (double-walled UST systems with interstitial monitoring) is required.  
  • No regulated UST system (including tank, piping and dispensers) may be installed within 50 feet of any other well used for human consumption. Regulated UST systems may be installed between 50 and 100 feet of any other well used for human consumption, but secondary containment (double-walled UST systems with interstitial monitoring) is required.

All UST systems installed on or before January 1, 1991 that met “new tank system” performance standards (corrosion protection, spill prevention and overfill prevention) by that date are excluded from these siting and secondary containment regulations.

Evidence of a suspected release includes product present in containment sumps, stained soil from an overfill, and/or any growth of the piping or other unusual conditions. Evidence of a release requires that the release be reported and investigated. Release that are 25 gallons or greater must be reported and cleaned up. Owners and/or operators may not know that must report releases less than 25 gallons which cannot be cleaned up within 24 hours.

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