Underground Storage Tank Program

The Yolo County Environmental Health Department regulates underground storage tank (UST) systems to help prevent hazardous materials from contaminating the environment and groundwater. The program ensures USTs are installed, operated, maintained, repaired, and removed safely and in compliance with state and federal regulations.

Conduct state-mandated annual inspections of all UST systems
Review and approve all permit applications for UST installations, repairs, upgrades and modifications
Conduct installation, repair and removal inspections
Conduct plan checks for all new installation proposals
Ensure that business operating underground storage tanks are properly permitted and meet the monitoring requirements specified in state and federal laws and regulations
Oversee site clean-up and remediation of UST sites identified as contaminated

State law mandates that all underground storage tank systems be inspected on an annual basis. Facilities should make all attempts to have a site representative available during these times to meet with the inspector. For guidance on how to prepare for a UST inspection, please call 530-666-8646 and request the UST Self-Audit Checklist.

UST Designated Operator Information & Training Requirements

Since January 1, 2005, all underground storage tank (UST) facilities must have a Designated Operator. The Designated Operator is responsible for training facility employees and conducting monthly inspections of the UST system. If your facility changes Designated Operators, notify the Yolo County Environmental Health Division in writing.

Designated Operator Responsibilities

Hold a current California UST System Operator certification issued by the International Code Council.
Train new employees within 30 days of hire and provide refresher training every 12 months.
Conduct monthly visual inspections and provide inspection reports to the facility owner or operator.

Employee Training Must Include

Proper operation of the UST system.
Use of monitoring equipment.
Spill and overfill response procedures.
Emergency contacts and alarm response.

Required On-Site Records

Designated Operator Statement with contact information and ICC certification number.
Monthly inspection reports for the previous 12 months.
Employee training records documenting initial and annual refresher training.

New UST Construction/Installation

Underground storage tanks (USTs) and piping must meet strict construction standards to prevent leaks and protect the environment. USTs installed or replaced after July 1, 2004, must use continuous leak monitoring for all underground system components, including tanks and piping.

Permit review begins only after a qualified contractor is identified on the application. Contractors must provide proof of current ICC Certified UST Installer certification, which must be renewed every 24 months. For more information on the certification process please refer to the International Code Council homepage or to the State Water Resources Control Board Training Certification page.

Plan review begins once all required documents are submitted and typically takes about two weeks. Additional review time for revised plans may be billed at an hourly rate.

Construction may not begin until the Yolo County Environmental Health Department issues an Authority to Construct letter. The letter outlines project-specific requirements and inspection procedures. Property owners are responsible for obtaining any additional permits required by other agencies before work begins.

A copy of the Authority to Construct letter must be kept on-site throughout construction. Required inspections must be scheduled with a Yolo County Hazardous Materials Specialist at least 48 hours in advance by calling (530) 666-8646.

UST Repairs/Upgrades/Modifications

The Yolo County Environmental Health Division classifies underground storage tank (UST) repairs, modifications, and upgrades as major, minor, or no permit required, based on the scope of work and inspection requirements. Major repairs typically require multiple inspections and may include soil or groundwater sampling, while minor repairs require a single inspection. Refer to the Repair Classifications Guidance to determine the appropriate category for your project.

For work that does not require a permit, contractors should contact the Yolo County Environmental Health UST inspector assigned to the facility to determine whether an inspection is required. After the work is completed, contractors should submit a Description of Repair Work Completed form to our office within five business days.

All contractors performing work on an underground storage tank (UST) system must provide proof of current ICC Certified UST Service Technician International Code Council home certification. For certification information, visit the International Code Council homepage or the State Water Resources Control Board Training Certification.

UST Removals/Closures

Underground storage tanks (USTs) may be removed due to leaks, property redevelopment, or the discovery of an unregistered tank. A permit is required to remove any UST in Yolo County, regardless of its size.

Yolo County Environmental Health requires tanks to be permanently removed whenever possible. Requests to abandon a tank in place are reviewed on a case-by-case basis and are approved only when removal would damage an existing building or structure. On-site cutting and cleaning of USTs is not permitted due to safety risks.

Temporary abandonment of a UST is allowed for up to one year. Requests for a one-year extension are reviewed on a case-by-case basis. During temporary abandonment, the UST must be disconnected from its power source and cannot receive fuel deliveries.

A Yolo County Environmental Health representative must witness all UST removals and temporary abandonments. Inspections must be scheduled at least 48 hours in advance by calling (530) 666-8646.

Leaky UST Site Information

When a leak is found to have occurred from underground tank and/or piping systems, the owner or operator of the facility is required to take immediate steps to stop the leak from continuing. Once this step has been completed an investigation is required to determine the extent of soil and/or ground water contamination. Based on the findings of the investigation, a determination is made whether active clean up, monitoring, or additional investigation is necessary. The lead agency for oversight of these cases can be either the Yolo County Environmental Health Division or the Central Valley Regional Water Quality Control Board.

Useful UST Links

High temperatures are expected across Yolo County. If you need relief from the heat, find local cooling locations through Yolo County Places to Cool.