Underground Storage Tank (UST) Facility File Selection Process

In preparation for a Certified Unified Program Agency (CUPA) Performance Evaluation, the State Water Resources Control Board (State Water Board) will identify and select UST facilities within a CUPA’s jurisdiction for review. State Water Board Evaluation staff use the following UST facility file selection criteria to select the appropriate number and type of facility files to include in the CUPA Performance Evaluation.

File Selection

The number of UST facilities within a CUPA’s jurisdiction is determined using the most recent Report 6 UST facility count.

The number of UST facilities within a CUPA's jurisdiction is determined using the most recent Report 6 UST facility count. The table below depicts the minimum and maximum number of facility files that typically will be requested per total number of CUPA UST facilities:

Selection Criteria

Staff consider the following criteria when determining the number of facility files to review, including but not limited to:

Single Walled USTs

Single-walled USTs and non-exempt single-walled piping were required to be permanently closed by December 31, 2025, pursuant to Health and Safety Code, chapter 6.7 (H&SC, 6.7). Any single-walled UST that has not been permanently closed is considered out of compliance and should no longer be in operation.

Generally, testing results for single-walled UST systems will not be included in the facility file request. Instead, staff will request inspection and enforcement documentation for single-walled UST facilities that failed to meet the closure deadline. CUPAs should provide all inspection and enforcement documentation, including correspondence when submitting facility files.

Note: For single-walled USTs still in the ground, evaluation staff will request copies of required UST testing results.

Previous Evaluations

CUPAs that have been approved for paperless Report 6 and have historically provided complete and accurate facility files during previous evaluations may have a reduced number of facility files requested in future evaluations. While previous evaluations are considered, the evaluation staff has the discretion to select from the number of UST facility files requested as outlined in the table above.

UST Construction Configurations and Status

Staff also consider the following UST system information during facility file selection:

• Tank Construction
• Piping Construction
• Line Leak Detectors and Monitoring Systems
• Public or Private UST ownership
• Closures, Temporary Closures and Abandoned USTs

Emergency Tank Systems

Due to more complex and unique configurations of emergency tank systems, the evaluation staff may select at least one emergency tank system facility for review. In recent evaluations, staff have observed an increase in non-compliant emergency tank systems.

Participating Agencies (PAs)

If the CUPA has one or more PAs, evaluation staff will identify and select facilities using the same criteria described above.

Note: The decision on the number and type of facility files requested during the CUPA Performance Evaluation is not negotiable and will be determined exclusively by the State Water Board. Staff may request additional files during the evaluation, if necessary, and use information in the California Environmental Reporting System (CERS) prior to or during the evaluation period. Information that is captured from CERS and used by staff during the evaluation may be shared with the CUPA upon request.