Underground Storage Tank (UST) Program

Low-Threat Underground Storage Tank Case Closure Policy

This policy is a state policy for water quality control and applies to all petroleum UST sites subject to Chapter 6.7 of Division 20 of the Health and Safety Code and Chapter 16 of Division 3 of Title 23 of the California Code of Regulations.

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Additional Actions to Improve the Underground Storage Tank Cleanup Program

On November 6, 2012, the State Water Board approved the Plan for Implementation of Low-Threat Underground Storage Tank Case Closure Policy and Additional Program Improvements (Plan). See State Water Board Resolution No. 2012-0062.

The approved Plan: (1) implements the Low-Threat Underground Storage Tank Case Closure Policy (Policy) adopted by the State Water Board under Resolution No. 2012-0016, and (2) summarizes other actions to improve the administration of the UST Program. The Plan is intended to provide consistent application of the Policy and consistent implementation of the UST Program in general, throughout the state. The Plan’s major elements related to implementing the Policy are to specify the roles and responsibilities of the agencies in implementing the Policy. The Plan’s major elements related to UST Program improvement are to provide: (1) focus on high-priority cases (such as impacted drinking water wells, other human health impacts, and sources of free product still remaining in place), and (2) for development of Path to Case Closure Plans for each open case, including specific milestones and timelines.

Resolution No. 2012-0062 directs State Water Board staff and regulatory agencies (Regional Water Boards, local oversight program agencies, and other local agencies) to aggressively implement the Plan and to take a number of additional actions to improve the UST Program. Resolution No. 2012-0062 also directs State Water Board staff to review a regulatory agency’s decision when the regulatory agency has denied a request by a responsible party for case closure pursuant to the Policy, and propose case closure, as appropriate, within six months of the update to GeoTracker indicating closure denial.

State Water Board staff developed frequently asked questions (FAQs) to help all parties (regulatory agency staff, responsible parties, Fund claimants and consultants) better understand the Policy and the basis for the Policy. These FAQs are intended to normalize the implementation of the Policy and ensure consistent application of the Policy throughout the state. These FAQs will be an “evergreen” document, and will be updated and revised as necessary in the future.

Low-Threat UST Case Closure Policy (effective August 17, 2012)

On May 1, 2012, the State Water Board adopted a Low-Threat Underground Storage Tank Case Closure Policy. See State Water Board Resolution No. 2012-0016. The Policy was approved by the Office of Administrative Law (OAL) on July 30, 2012.  On August 17, 2012, the Notice of Decision was filed with the California Secretary for Natural Resources, and the Policy became effective.

The Policy applies to petroleum UST sites subject to Chapter 6.7 of the Health and Safety Code. The Policy establishes both general and media-specific criteria. If both the general and applicable media-specific criteria are satisfied, then the leaking UST case is generally considered to present a low threat to human health, safety and the environment. The Policy recognizes, however, that even if all of the specified criteria in the Policy are met, there may be unique attributes of the case or site-specific conditions that increase the risk associated with the residual petroleum constituents. In these cases, the regulatory agency overseeing corrective action at the site must identify the conditions that make case closure under the Policy inappropriate.

Under existing policy, regulatory agencies consider site-specific conditions when determining if the level of corrective action ensures the protection of human health, safety and the environment pursuant to Health and Safety Code section 25296.10, subdivision (g). With the knowledge and experience gained over the last 25 years of investigating and remediating petroleum UST releases, site conditions and characteristics have been identified that if met, will generally ensure the protection of human health, safety and the environment. This Policy identifies those standardized criteria. The Policy is necessary to establish consistent, statewide case closure criteria for low-threat petroleum UST sites in California.


Regional Water Boards and local agencies have been directed to review all cases in the petroleum UST Cleanup Program using the framework provided in the Policy. This review shall be accomplished within existing budgets and be performed no later than 365 days from the effective date of this Policy.

These case reviews shall, at a minimum, include the following for each UST case:

  1. Determination of whether or not each UST case meets the criteria in the Policy or is otherwise appropriate for closure based on a site-specific analysis.
  2. If the case does not satisfy the criteria in this Policy or does not present a low-risk based upon a site-specific analysis, impediments to closure shall be identified.
  3. Each case review shall be made publicly available on the State Water Board's GeoTracker web site in a format acceptable to the Executive Director.

A "Checklist"” has been developed by State Board staff as a tool to assist all parties in determining if a site meets the criteria in the Policy.

Adoption Hearing

The State Water Board conducted an Adoption Hearing on Tuesday, May 1, 2012 and adopted Resolution No. 2012-0016 that approved a Substitute Environmental Document and adopted a Water Quality Control Policy for Low-Threat Underground Storage Tank Case Closure.

Public Hearing

The State Water Board conducted a Public Hearing for the receipt of oral comments on a Draft Policy and Draft SED on Tuesday, April 17, 2012. No Board action was taken.

The public comment period for both the Draft Policy and Draft SED ended March 19, 2012  »»   See Comments

CEQA Scoping

The adoption of policies for water quality control has been certified as an exempt regulatory program under the California Environmental Quality Act (CEQA).

The State Water Board held public scoping meetings to gather input from public agencies and interested persons on the scope and content of the environmental documentation to be prepared for this project.

The public comment period ended November 8, 2011.

Peer Review

Health and Safety Code Section 57004, requires all Cal/EPA organizations to submit for external scientific review the scientific basis and scientific portion of all proposed policies, plans and regulations. The peer reviewer’s responsibility is to determine whether the scientific findings, conclusions, and assumptions are based upon sound scientific knowledge, methods, and practices. Go to the State Water Board’s Peer Review web page.

Policy Stakeholder Group

The Draft Low Threat UST Closure Policy was developed by a group of nine individuals from several different California UST stakeholder groups including two Regional Water Quality Control Board (RWQCB) agencies, a Local Oversight Program (LOP) agency, a water district, responsible party (RP) representatives from the Western States Petroleum Association (WSPA) and California Independent Oil Marketers Association (CIOMA), two participants from Non-Government Organizations (NGOs), and one UST consultant.

Regulatory Outreach Proposed Petroleum Low-Threat Closure Policy

Documents Developed by the UST Stakeholder Group