UST Program - Cleanup

An Introduction to Leaking Petroleum Underground Storage Tanks

Leaking underground storage tanks are a significant source of petroleum impacts to groundwater and may pose the following potential threats to health and safety:

  • Exposure from impacts to soil and/or groundwater
  • Contamination of drinking water aquifers
  • Contamination of public or private drinking water wells
  • Inhalation of vapors

These threats are minimized when UST owners or operators (responsible parties) report a leak to the environment to the local regulatory agency within 24 hours of detection, as required. Regulatory Agencies are ready to assist UST responsible parties in responding to leaking USTs. If you are the owner or operator of an underground storage tank that has encountered an unauthorized release (leak), you are required to report the leak and may be required to perform a soil and groundwater investigation and/or cleanup under the direction of the lead regulatory agency.

If a leak occurs, responsible parties or their representative must notify the appropriate Regional Water Quality Control Board or County Agency and submit an unauthorized release form. Site investigation and cleanup (corrective action) costs can only be reimbursed by the Cleanup Fund after the tank release has been reported to the Regional Board or county regulatory agency.

Regional Board and many County Agencies are authorized to oversee the investigation and cleanup of UST system releases.

Leak Reporting Requirements

Owners and operators of USTs who have reported a release to the Regional Board or County will be notified by the appropriate regulatory agency if corrective action is required. The following chronology is a brief explanation of regulatory requirements:

  • 24 Hour Report
    Owners or operators should notify the regulatory agency within 24 hours of detection. Every step should be taken to stop the leak and empty the tank if necessary.

    NOTE: A leak that is contained within a tank system is not subject to the same reporting requirements as a release into the surrounding soil-water environment.
  • 5 Day Report
    This is a report on which the owner or operator is required to submit the local regulatory agency within five working day of discovering a leak.
  • Free Product Removal Report
    Free product refers to petroleum that floats on top of the water surface as opposed to being dissolved in the water. The owner or operator is required to remove as much free product as practicable, and submit a report within 45 days of a reported release. This report documents the extent of, and the actions taken to recover free product.
  • Quarterly Reports
    During investigation and cleanup, owners and operators must submit reports to the county agency or regional board once every quarter, or as specified by the regulatory agency. Geotracker is the state's Internet-accessible database for groundwater and environmental data and is the vehicle for Electronic Data Reporting. It tracks regulatory data about UST sites and public drinking water wells, as well as other types of data. Go to the Electronic Data Reporting Page.

Finding a Consultant

Choosing an environmental consulting firm to perform the required investigation and cleanup will probably be the most difficult and time consuming task required of you in the corrective action process. It is also the most important task. No other single factor, within your control, will affect the cost, duration, and overall frustration level of corrective action. You are advised to take this task very seriously and proceed with caution. Get more information about finding a consultant or contractor.

Site Assessment and Cleanup

  • Site Assessment
    If a UST leak occurs, the owner or operator (Responsible Party) must report the leak to the local regulatory agency. Soil and/or groundwater assessment may be required by the lead regulatory agency. Assessment and cleanup is governed by the Porter Cologne Water Quality Control Act (Water Code) and Chapter 16 (Article 11) of the Underground Storage Tank Regulations. Results of the assessment provide details about the size and magnitude of the release and are used to determine an appropriate cleanup strategy. A good site assessment study can be used to recommend one of several cleanup alternatives (feasibility study). Get more information about Site Assessment.
  • Cleanup
    Cleanup is conducted under the direction of the lead regulatory agency and may include free product removal, vapor extraction, ozone sparging or technologies such as groundwater extraction, for example. In some cases, soil excavation and disposal completes the cleanup. Get more information about Cleanup.
  • Evaluating Alternative Cleanup Technologies
    Evaluating alternative cleanup technologies requires an understanding of site specific conditions and the nature and extent of the contamination. Data from site assessment studies can be used to recommend one of several cleanup alternatives. Conducting extended interim remedial actions without concurrent evaluation of alternative cleanup technologies should be avoided. A responsible party must be aware of inherent limitations of a chosen cleanup alternative given the specific conditions of the site. Finally, the evaluation of alternative cleanup technologies should include cleanup objectives and estimated times to reach those objectives. Get more information about Evaluating Alternative Cleanup Technologies.
  • Path to Closure Meetings
    Path to Closure Meetings can be requested by the Lead Regulatory Agency or Responsible Party for a UST cleanup case that does not have an active claim with the UST Cleanup Fund. These meetings provide an opportunity for the Lead Regulatory Agency and Responsible Party to negotiate a path to closure with the assistance of State Water Board staff. Details regarding Path to Closure Meetings can be found in the State Water Board’s “Path to Closure Meeting Process” document.

Case Closure

An Underground Storage Tank (UST) case qualifies to receive a "Uniform Closure Letter" (UCL) once the owner or operator meets appropriate corrective action. State Water Resources Control Board (State Water Board) has adopted a Low-Threat Underground Storage Tank Case Closure Policy (Policy) to establish consistent statewide case closure criteria for low-threat petroleum UST sites. Cases that meet the criteria in this Policy do not require further corrective action and shall be issued a UCL consistent with Health and Safety Code section 25296.10.

Any owner or operator, or other responsible party who has an underground storage tank case and who believes that the corrective action plan for the site has been satisfactorily implemented may submit a request for closure (RFC) to the lead regulatory agency. If the RFC is denied by the lead regulatory agency, the State Water Board will automatically review the denial per Resolution 2012-0062. One may track the progress of the review of denied RFCs on GeoTracker’s "Closure Denial Review Report". Additionally owners or operators may appeal to the State Water Board for case closure per H&SC 25296.40. In general, a responsible party may petition the State Water Board for case closure after the site has been adequately characterized, remediated, and it is demonstrated that the Criteria of the Policy have been met or that Water Quality Objectives will be achieved within a reasonable timeframe (State Water Board Resolution No. 92-49, Amended by Resolution 96-0079, October 2, 1996). The State Water Board may dismiss the petition, or formally hear the matter at a State Water Board meeting for a closure decision. For more information about how to file a closure petition or other UST related petition, visit State Water Board UST petition page.

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