Underground Storage Tank Program

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Program Information

The Yolo County Environmental Health Department regulates the construction, operation, repair and removal of underground storage tank systems (UST’s) throughout Yolo County. The purpose of the UST program is to ensure that hazardous materials being stored in underground storage tanks are not released into the environment and/or groundwater.

Hazardous Materials Specialists working in the UST program:

  • 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


Over 300 UST’s at 109 regulated facilities


California Health & Safety Code chapter 6.7
Title 23 California Code of Regulations

New UST Construction/Installation

 Underground Storage Tank Construction/InstallationTanks and associated piping systems are required to meet stringent construction standards designed to reduce the potential for product loss. All tanks installed after July 1, 2004 (or upgrades completed after this date that involve replacing the underground storage tank) must be continuously monitored using vacuum, pressure, or interstitial liquid level measurement methods. This holds true for ALL parts of the underground storage tank system including the interstitial space of the tank and product piping (including fill, vent, and vapor recovery piping) that are underground.

When an underground storage tank application is submitted, the permit review process will not begin until a contractor has been specified on the application. Contractors installing underground storage tank systems must submit documentation confirming their status as an ICC Certified UST Installer. Please note that this certification 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.

The plan check process will begin once all required documentation has been submitted. Plan checks take an average of two (2) weeks. Re-submittals will be handled on a case-by-case basis and billed an hourly rate for the additional review time.

Final approval will be granted via an ‘Authority to Construct’ letter issued by the Yolo County Environmental Health Department. Copies of this letter will be sent to both the property owner and the contractor performing the work. It will list site-specific construction requirements and inspection scheduling requirements. No UST construction activities can proceed prior to the issuance of this letter. Upon receipt of your approval letter, work can begin. Additional permits may be required from other agencies including the Yolo-Solano Air Quality Management District , the local planning/building agency and/or the local fire district. It is your responsibility to ensure that you have received all permits necessary before beginning work. Once work commences, you must keep a copy of your ‘Authority to Construct’ letter on site at all times. Several inspections will be required during the installation or repair process. These inspections must be scheduled with a Yolo County Hazardous Materials Specialist at least 48 hours in advance. Inspections may be scheduled by calling (530) 666-8646.

UST Installation Application packets can be downloaded here. For fee requirements please refer to the Yolo County Fee Schedule


UST Repairs/Upgrades/Modifications

Underground Storage Tank Upgrades The Yolo County Environmental Health Division classifies underground storage tank repairs, modifications and upgrades into one of three categories: major, minor, or no permit necessary. These categories are determined by the scope of work and the number of inspections necessary. A major repair/modification involves more than one inspection and may include soil and/or ground water sampling. Minor repairs/modifications require only one inspection and do not involve soil and/or ground water sampling. For assistance in determining the classification of repairs to be made to your underground storage tank system please refer to our Repair Classifications guidance. For fee requirements please refer to the Yolo County Fee Schedule.

Underground Storage Tank RepairsFor work not requiring a permit, contractors should contact the Yolo County Environmental Health UST inspector assigned to the facility where work is to be completed to determine if an inspection is necessary. Although some repairs do not require a permit, Yolo County requests that after completing the work a “Description of Repair Work Completed”form is submitted to our office within 5 business days. Please note that any contractor performing work on an underground storage tank system must be prepared to submit documentation verifying their certification as an ICC Certified UST Service Technician. 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


 UST Removals/Closures

Underground Storage Tank RemovalUnderground storage tanks may be removed for a variety of reasons including the discovery of a leak in the system, property redevelopment, or discovery of a tank that was not known to exist. A permit is required to remove any underground storage tank in Yolo County, regardless of the size of the tank.

It is the policy of the Yolo County Environmental Health Department to have all tanks permanently removed, rather than abandoned in place, whenever possible. To download an application for a UST Removal please click here Applications requesting to abandon an underground storage tank in place will be thoroughly reviewed and will only be approved in cases where removal of the tank will cause damage to an existing building or structure. Yolo County also does endorse the onsite cutting and cleaning of an underground storage tank due to the inherent danger of the operation. To download an application packet to abandon an underground storage tank in place please click here. For fee requirements for both permanent removals and tank abandonment in place please refer to the Yolo County Fee Schedule

Yolo County also allows the temporary abandonment of an underground storage tank system for a period not to exceed one year. Temporary abandonment extensions for a period of one additional year will be reviewed on a case-by-case basis. While temporarily abandoned, the UST system must be disconnected from the power source and may not receive fuel deliveries. To download an application packet to temporarily abandon an underground storage tank system please click here. For fee requirements for both permanent removals and tank abandonment in place, please refer to the Yolo County Fee Schedule. A representative of the Yolo County Environmental Health Division must witness all UST removals and temporary abandonment. These inspections must be scheduled a minimum of 48 hours in advance. To schedule an inspection please call us at (530) 666-8646.


UST Operating Permits and Inspections

The Yolo County Environmental Health Division issues an annual operating permit to facilities operating underground storage tanks. This permit is mailed to the facility-specified address each year. Operating an underground storage tank without a valid permit is a violation of State Law. Operators should ensure that their valid permit is displayed in a conspicuous location within their facility. Permits will not be issued unless a facility is in full compliance with all laws and regulations, and all fees have been paid. If you have not received a copy of your current permit, please contact us at (530) 666-8646 to discuss possible reasons for this.

State law mandates that all underground storage tank systems be inspected on an annual basis. The Yolo County Environmental Health Division generally conducts these inspections during annual testing required by the state. 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 refer to the “UST Self-Audit Checklist



 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.

We maintain an electronic list of known leaky sites and have files with detailed information about most of these sites in Yolo County. Our files are open for a free public review on Wednesday mornings and by appointment at other times for a small fee. By calling ahead and letting us know which facility files you would like to review, we can serve you better by having the files ready and space reserved when you arrive. For further information on public files reviews including information about setting up an appointment please click here.


UST Designated Operator Information & Training Requirements

Beginning January 1, 2005 all underground storage tank facilities were required to provide proof that they have a Designated Operator for their facility. A Designated Operator is an individual designated by the UST operator to have responsibility for training facility employees on the UST system and conducting a monthly inspection of the UST facility. If your facility changes designated operators you must notify the Yolo County Environmental Health Division in writing. Forms are available here.

The designated operator must:

  • Posses a current “California UST System Operator” certification issued by the International Code Council (ICC). 
  • Provide on-the-job training for facility employee(s). Initial training was required by July 1, 2005. Facility employees hired on or after July 1, 2005 must complete initial training within 30 days from their date of hire.
  • Perform monthly visual inspections and record results on an inspection report, which must be provided to the owner/operator.

The training provided by the Designated UST Operator to the facility employees must be conducted within 30 days of hire and every 12 months thereafter and must include at minimum:

  • The operation of the UST system in a manner consistent with the facility’s best management practices.
  • The facility employee’s role with regard to the monitoring equipment as specified in the facility’s monitoring plan.
  • The facility employee’s role with regard to spills and overfills as specified in the facility’s response plan.
  • The name of the contact person(s) for emergencies and monitoring equipment alarms.

Facility operators should maintain on site the following:

  • UST Designated Operator Statement showing the contact information and ICC Certification number of the person serving as the facility’s designated operator
  • Copies of the monthly inspection reports completed by the designated operator for the previous twelve (12) months
  • Training logs showing that all employees have received initial training from the designated operator and refresher training every 12 months thereafter


Frequently Asked Questions

 Who can serve as a Designated UST Operator?

Persons wishing to act as a Designated UST Operator are required to possess a current California UST System Operator certificate. In addition, it is the responsibility of any person wishing to act as a Designated UST Operator to ensure that they comply with other applicable state, federal or local requirements. The Designated UST Operator could be the facility owner, operator, employee, service technician, or a third party. For more information on the certification process please refer to the International Code Council homepage

 What paperwork am I required to maintain on-site?

For a list of requirements that apply to underground storage tank facilities including a list of documentation that is required to be maintained on-site please refer to the “UST Self-Audit Checklist

 What testing am I required to perform on my UST system?

Underground storage tank systems in the state of California are required to complete different types of testing depending on when the system was installed and the capabilities of the monitoring system. The best way to determine what testing your facility is required to complete is to call us and speak to the underground storage tank inspector assigned to your facility. We can be reached Monday thru Friday 8:00am – 5:00pm at (530) 666-8646.

I received a letter stating that I have testing coming due. Why did I receive this?

The Yolo County Environmental Health Division sends out automatically generated letters 60 days and again 30 days before any testing and/or financial responsibility documents are due for your facility. These letters are sent as a courtesy reminder to help you schedule your testing on time to avoid potentially costly violations.

Where can I get a list of licensed UST contractors?

Yolo County Environmental Health has a list of contractors that are licensed to do various types of work. This list is not an endorsement of any of the contractors or companies listed. For a copy of this list please click here.


Useful UST Links 


 Contact Us

 Yolo County Environmental Health Department
Underground/Aboveground Storage Tank Specialist
292 West Beamer Street
Woodland, CA 95695

Call: (530) 666-8646
Fax: (530) 669-1448



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