Part 3: Underground Storage Tank (UST) Requirements

September 11, 2017


In our last post, we discussed requirements for businesses that generate, handle, store, and ship hazardous waste. In this post, we focus on hazardous material Underground Storage Tank (UST) requirements.


What kinds of underground storage tanks are regulated?

With few exceptions(1), any tank system (including the piping) that is completely or partially buried and contains a hazardous material is regulated by Federal and California laws and regulations.


Why are USTs Regulated?

USTs are heavily regulated for a reason. USTs, if left unattended, will leak. There have been 120,322 confirmed leaking tank systems in the United States. At the end of the 2016 Fiscal Year, 18,546 remain active clean-up sites. Most of these leaking tank systems were single-walled with single wall-piping with little or no electronic leak monitoring. Modern USTs and piping have double walls and other secondary containment spaces to prevent leaks from entering the ground and ground water. In addition, secondary containment spaces are electronically monitored. If there is a primary containment system leak, the monitoring system will go into alarm mode and notify the operator that there is a problem before contaminants can enter the environment.


Who permits, regulates and inspects USTs in California?

Underground storage tanks in California are regulated by the local Certified Unified Program Agency (CUPA). The local CUPA is responsible for enforcement and permitting. Your CUPA is obligated to inspect every tank system annually. Inspections will almost always occur at the same time as the annually-mandated monitoring system certification. Your local CUPA also issues permits to operate a UST within their jurisdiction.


California Environmental Reporting System (CERS) Requirements for USTs

If your facility has a UST, the following additional items will need to be submitted on CERS:

  1. UST Facility Operating Permit Application

  2. UST Tank Information/Monitoring Plan

  3. UST Certifications of Installation/Modification

  4. UST Monitoring Site Plan

  5. UST Certification of Financial Responsibility

  6. UST Response Plan

  7. UST Owner/Operator: Written Agreement

  8. UST Letter from Chief Financial Officer (If using State Coverage to show financial responsibility)

  9. Owner Statement of Designated UST Operator Compliance

Testing Requirements for USTs

Most tanks need to have the following tests completed annually:

  1. Monitoring System Certification

  2. Electronic or mechanical line leak detection testing

  3. Spill Containment Testing

Every three years most tanks systems must conduct:

  1. Secondary Containment Testing. However, tanks that continuously monitor the secondary containment spaces for leaks, using vacuum, pressure or hydrostatic (VPH), are exempt.

  2. Enhance Leak Detection is required every three years if tank is located within 1,000 feet of a drinking water well and has single-walled components.


California Designated UST Operator (DUSTO) Requirements:

California regulations require an International Code Council (ICC) certified DUSTO to conduct a monthly inspection of the UST system. The “Designated UST Operator” should not be confused with the “operator” of the tank system who is in control of day-to-day operations. Both of these definitions can be found in 23 CCR 2610. The inspection Designated UST Operator Inspections include:

  1. Reviewing alarm console for proper operation

  2. Reviewing alarm history for evidence of a leak in system or water intrusion

  3. Verifying secondary containment spaces are free of liquid, debris and hazardous substances

  4. Reviewing documentation to ensure all required testing has been conducted in a timely manner.

In addition, the DUSTO must provide training for all new employees and provide training annually for existing employees. This training is expected to include:

  1. The best management practices for operation of the UST system

  2. How the monitoring system works and how to respond to alarms

  3. Responding to spills, overfills and other emergencies

  4. Emergency contacts for the facility

Records of training must be maintained on site for 36 months. Also, during business hours there needs to be a minimum of one person on-site who has received the required training.

If you have further questions about UST compliance, feel free to contact us at


Next, Part 4: Above ground Storage Tanks


(1) Underground Storage Tanks that are exempt from California and Federal regulations:

  • Farm and residential tanks of 1,100 gallons or less capacity holding motor fuel used for noncommercial purposes

  • Tanks storing heating oil used on the premises where it is stored

  • Tanks on or above floor of underground areas, such as basements or tunnels

  • Septic tanks and systems for collecting storm water and wastewater

  • Flow-through process tanks

  • Tanks of 110 gallons or less capacity

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