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Underground Storage Tanks: Heating Oil USTs


This fact sheet outlines the regulatory requirements associated with underground storage tanks (USTs) that store fuel oil for direct consumptive use (referred to here as heating oil USTs). Heating oil USTs are no longer utilized at the University of Maryland; the University does not intend to initiate the placement of USTs on campus. This Fact Sheet does not address motor fuel, used oil or emergency generator USTs. Regulatory requirements for such USTs are presented in the Compliance Officer Sheet entitled "Underground Storage Tanks: Motor Fuel, Used Oil and Emergency Generator USTs."

Heating oil USTs are regulated by the Maryland Department of the Environment (MDE).


Consumptive Use: Fuel oil used exclusively for area heating and/or heating of domestic water on the premises where stored.

Existing facility: A tank system whose construction, installation, or operation began prior to December 31, 1986.

Flammable and combustible liquids: A flammable liquid is any liquid having a flash point below 100°F. Flammable liquids are known as Class I liquids and are divided into the following classifications: Class IA, Class IB and Class IC (depending on flash point levels). A combustible liquid is any liquid having a flash point at or above 100°F. Combustible liquids are also known as Class II or Class III liquids.

New or Replacement facility: A tank system whose construction, installation or operation commenced on or after December 31, 1986.

Underground Storage, Underground Storage Tank (UST): An underground storage tank, connected underground piping, underground auxiliary equipment and containment system if any. 10% or more of the tank volume and piping must be underground. A UST does not include a free-standing container within a building.

Applicable University Policy

University of Maryland Environmental, Safety and Health Management Policy

Applicable Regulation

  • COMAR 26.10- Oil Pollution and Tank Management
  • 40 CFR Part 280- Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks (UST).

Summary of Requirements

This section provides an overview of the operational requirements found in MDE regulations. These regulations include requirements related to UST notification/permitting, leak detection, tightness testing, upgrading of existing USTs, abandonment and/or removal and response to releases. Heating oil USTs are subject to the requirements outlined in this section. ESSR must be notified of the installation, modification, or removal of all University owned and operated Heating oil USTs.




  1. Registration: USTs are required to be registered with MDE. Registration forms are completed by the Department of Environmental Safety, Sustainability and Risk (ESSR).
  2. Leak Detection, Tightness Testing and/or Inventory Requirements: Heating oil USTs installed prior to March 15, 1985 must:
    • Be gauged prior to filling;
    • Be precision tested at 15 years of age and every 5 years thereafter; and
    • Have filled pipes marked in accordance with the American Petroleum Institute (API) guidelines.

  3. Inventory Methods: If the UST does not meet new tank design standards, then monitoring must be conducted through:


    • A daily inventory system consisting of the maintenance and reconciliation of daily inventory records. The inventory is based on the actual daily measurement and recording of tank product and water levels. Daily measurements may be conducted with a gauge, gauge stick or by a readout from an automated gauging system. The records must include a daily computation of gain or loss. At the close of each calendar month, the owner must determine the number of days in which any amount of product was dispensed and the number of days in which a product loss was recorded. If the computations indicate a release of greater than 0.5% of the volume of product in the tank, an abnormal release has occurred and additional remedial steps are required;



    • The use of monthly monitoring controls and annual tightness testing.

      Heating oil tanks installed after March 15, 1985 must:

      • Be gauged prior to filling;
      • Have corrosion protection;
      • Be installed by a certified technician;
      • Be precision tested prior to first use;
      • Be equipped with 2 monitoring pipes in the tank field;
      • Have pipes marked according to API guidelines;
      • Be precision tested at 15 years of age and every 5 years thereafter;
      • Have spill and overfill protection.

  4. Upgrading Existing USTs: All existing heating oil USTs with a capacity of greater than 1,100 gallons, must be retrofitted with a spill containment manhole and an overfill prevention device. An overfill prevention device may include an automatic flow shutoff or a high level alarm.

    All heating oil USTs should be equipped with specific leak detection components. In the interim, USTs without leak detection components are required to satisfy specific leak detection and testing requirements on a case-by-case basis.

    Unprotected steel USTs and/or piping are required to be retrofitted with cathodic protection.

  5. Tank Abandonment and/or Removal: At least 30 days prior to removal, notification must be provided to MDE.

    USTs must be removed from the ground. However, in some instances, USTs may be located under a building or in a location such that its removal could endanger the structural integrity of another tank or structure. In these cases, USTs are typically abandoned in-place and must meet specific abandonment requirements.

  6. Response to Releases: In the event of a leak, whether determined by testing or otherwise, the following steps must be taken:
    • ESSR should be notified immediately;
    • MDE must be notified within 2 hours;
    • If testing indicates that the source of the leak is the tank, the tank must be emptied of all its product within 24 hours;
    • If testing indicates that the source of the leak is the piping, the tank must be taken out of service immediately.

MDE will determine immediate responsible actions.


It is recommended that University of Maryland personnel involved in petroleum delivery, storage and other aspects of UST management be familiar with this Fact Sheet.


Reporting requirements associated with USTs involve the MDE. The following are reporting-related requirements:

  • Change of service;
  • Tank removal/abandonment request;
  • Written notifications of tank and piping installations and upgrades; and
  • Release notification.


The owner of heating oil USTs must meet with the following record keeping requirements:

  • Maintain all records associated with each repair or relining for the remaining operating life of the UST system;
  • If applicable, records of cathodic protection monitoring, leak detection monitoring, inventory records and any other records shall be maintained and made available to MDE upon request;
  • If applicable, the negative voltage of cathodic protection systems equipped with a test wire and/or box shall be recorded at least annually.

University Resources

Department of Environmental Safety, Sustainability and Risk (301) 405-3960
ESSR Fax No. (301) 314-9294
ESSR Website:
Environmental Affairs (301) 405-3968

Written 5/98
Revised 5/03
Reviewed 4/05