Public Record Summary Information of Underground Storage Tanks

The State Water Resources Control Board (State Water Board) has prepared the data below, in compliance with the requirements of the National Energy Policy Act of 2005, summarizing the State of California’s total number of active underground storage tanks (USTs), active UST facilities, the number of UST facilities inspected between July 1, 2022 and June 30, 2023 and the findings from those inspections. Also provided below, is a summary of the source and cause of confirmed unauthorized releases from USTs reported during the same period.

Post Date: November 1, 2023

Summary of Information on Underground Storage Tanks

Data and Inspection Period:
July 1, 2022 – June 30, 2023
Total Active UST Facilities:
13,626
Total Number of Facilities Inspected:
13,505
Total Active UST Systems:
37,703
Percent of UST Systems in Compliance:
60.4% *

*In compliance indicates the UST system has met a series of performance measures developed by and reported to the United States Environmental Protection Agency (U.S. EPA). Other non-reportable violations, such as those not meeting specific state UST regulations, may also be included in the compliance percentage. More information on the U.S. EPA performance measure can be found on their UST Performance Measures web page.

UST Facility, System, Inspection and Compliance Information

The active number of UST facilities, UST systems and corresponding inspection information for this reporting period consists of 13,626 regulated UST facilities, of which 36,292 petroleum UST systems and 1,411 hazardous material UST systems were identified. These numbers, including the percent of USTs in compliance are based on those facilities and UST systems regulated pursuant to Subtitle I in 40 CFR 280.12 (except for tanks identified in 40 CFR 280.10(b) and 280.10(c)), California Health and Safety Code, division 20, chapter 6.7 and California Code of Regulations, title 23, division 3, chapter 16. The percent of UST systems in compliance is further measured using the Federal Technical Compliance Rate (TCR) as clarified by the State Water Board guidance on TCR criteria in LG-164-4. The TCR compliance data collection and reporting began on October 1, 2018 with the implementation of new California UST regulations.

Summary of UST Unauthorized Release Source and Cause (October 1, 2022– September 30, 2023)

Source Cause
Spill Overfill Physical or Mechanical Damage Corrosion Installation Problem Leak Detection Other Unknown Total
Tank 0 (%) 0 (%) 0 (%) 4 (31%) 0 (%) 0 (%) 0 (%) 9 (69%) 13 (100%)
Piping 0 (%) 0 (%) 0 (%) 0 (%) 1 (50%) 0 (%) 1 (50%) 0 (%) 2 (100%)
Dispenser 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 1 (100%) 1 (100%)
Turbine Sump 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%)
Delivery Problem 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%)
Other 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 0 (%) 16 (100%) 16 (100%)
Total 0 (%) 0 (%) 0 (%) 4 (13%) 1 (3%) 0 (%) 1 (3%) 26 (81%) 32 (100%)

* Data shown as number of releases (percent of total)

Data Sources

UST facility and compliance information is prepared biannually by local implementing agencies and collected by the State Water Board on March 1 and September 1 each year. The information presented on this page is a portion of the data reported to the U.S EPA. The additional information reported to U.S. EPA can be found at the U.S. EPA Performance Measures web page. For questions regarding compliance data for a specific UST facility, please visit the CalEPA directory for local implementing agency contact information.

Unauthorized release source and cause data is collected using State Water Board's Geotracker. Unauthorized release source and cause data is uploaded to Geotracker by the nine Regional Water Quality Control Boards and by counties approved by the State Water Board as a Local Oversight Program. For unauthorized release source and cause information at a specific location, please visit the Geotracker website.

Red Tag Data

Underground storage tanks determined to have a significant violation that poses an imminent threat to health, safety of the environment may have a red tags affix by the local implementing agency preventing that UST system from either accepting fuel deliveries or dispensing fuel. There are three categories of significant violation:

  • A violation causing or threatening to cause a release to the environment
  • A violation that impairs the leak detection system
  • A chronic violation committed by a recalcitrant violator

Information and data collection for affixed red tag can be found on the State Water Board Red Tag Data and Regulations web page.

For information about this page, please contact Tom Henderson or (916) 319-9128.