Underground Storage Tank System Closure/Removal:
California Law and regulations requires that if you own a property with underground storage tank (UST) system in the ground that has not been permitted for use for mote than one year you must permanently closure the UST by either legally removing the UST system or legally closing the tank in place by filling the tank with an inert solid such as concrete and typically, removing the piping see US EPA and SWRCB Tank Removal Requirements. You must obtain a permit from Solano County CUPA to either legally remove or legally close the UST system in place. Additionally, California Law and Regulations requires single wall UST systems to be permanently closed or upgraded by December 31, 2025.  For more information see Single Wall UST System Notification, Single Wall Tank System Removal Requirement Guidance,  UST Closure Application (Temporary, Closure In Place, & Removal). For specific requirements call (707) 784-6765 and ask for  the staff of the  Hazardous Materials Section.

Unauthorized Releases: 
An unauthorized release, as defined Health and Safety Code (H&SC) §25295, is a release which 1) escapes from a UST’s secondary containment, or from the primary containment, if no secondary containment exists, 2) increases the hazard of fire or explosion, or 3) causes any deterioration of the secondary containment of the underground tank system. An unauthorized release can happen at any moment—during tank fueling or by failure of tank, from the piping, at the dispensers, or from waste-oil tanks at service stations. Regardless of how or where the unauthorized release occurs, it is the responsibility of the owner or operator to respond and to report the release to Solano County CUPA and the applicable California Regional Water Quality Control Board.

Once an unauthorized release is detected, the first step is to take immediate action to stop the leak and prevent further release. This may require removing the residual product from the equipment in question. It is critical to determine whether any fire, explosion, or vapor hazards are present and, if so, to mitigate them. Tank owners or operators shall provide an initial report to the local agency within 24-hours and then follow up with a full written report within five working days. Owners and operators shall transmit information regarding an unauthorized release to the local agency on a written form or using an electronic format developed by the State Water Resources Control Board (State Water Board) and approved by the Secretary for Environmental Protection see Unauthorized Release Reporting Form

Release Reporting:
An Unauthorized Release Report needs to include information regarding an unauthorized release to the local agency on a written form or using an electronic format developed by the State Water Board and approved by the Secretary for Environmental Protection. The report shall include, but is not limited to, the following:

• Facility/site name, address, and telephone number;
• Discharge date or discovered date, and report date;
• Discharge cause and discharge source;