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Leaking Underground Storage Tank Cleanup

The State Water Resources Control Board contracts with Orange County to provide regulatory oversight for the cleanup of leaking underground storage tanks (USTs) under the Local Oversight Program (LOP) contract. The program services all the cities and unincorporated areas of Orange County except for the cities of Anaheim and Fullerton. 

LOP staff are responsible for:

  • confirming the release 
  • identifying and notifying Responsible Parties (RPs) 
  • reviewing and approving preliminary site assessment work plans to determine the type and extent of soil and groundwater contamination 
  • overseeing assessment activities 
  • reviewing assessment reports, quarterly reports, feasibility studies, risk appraisals, and corrective action plans 
  • issuing cleanup directives to the RPs 
  • overseeing cleanup operations 
  • approving and certifying cleanup operations 
  • completing all records 

Explaining the Requirements and the Process 

The RP shall undertake the following activities to identify the type and extent of the contamination caused by a released waste, initiate appropriate corrective action, and confirm that the corrective action has successfully mitigated the harmful effects of the release:

1. Site Assessment Work Plan: The site assessment work plan must:

  • define the lateral and vertical extent of contamination
  • determine the depth to groundwater
  • gather soil profile data

The work plan must also include:

  • release site history 
  • proposed number and location of soil borings/probes 
  • soil samples 
  • number and location of proposed groundwater monitoring wells/probes and water samples 
  • sampling methodology and laboratory analysis methods 
  • a health and safety plan where investigation activities could pose a threat to public health. 

This work plan can be implemented immediately after concurrence by LOP staff.

Well permits (see Water Quality)  must be obtained prior to beginning exploratory borings and construction of wells. LOP staff can assist in the identification of the appropriate agencies. All borings and abandoned wells must be properly sealed. Wells should be secured to prevent unauthorized access. Drilling procedures and well design and construction must be accomplished in a manner that prevents the spread of contamination, and should be developed by an appropriate registered professional (R.G., C.E.G. or equivalent) with expertise in subsurface investigations. 

Reports that include logs of soil borings or any findings or conclusions relating to the subsurface must be signed by a properly registered professional (R.G., C.E.G. or equivalent). 

2. Site Assessment Report and Remedial Action Plan:

After completion of the site investigation, the site assessment report outlining the findings must be submitted for review and concurrence.  

LOP staff will evaluate site contaminant data from the site investigation and discuss site cleanup goals considered protective of public health. Typically, this risk assessment evaluation includes the identification of potential exposure pathways (water, air, and direct contact) and quantitative prediction of exposure levels at human receptors. In general, soil cleanup goals for the protection of groundwater resources are not established. Guidance for groundwater cleanup goals is found in the most recent low-risk guidance documents distributed by the Santa Ana and San Diego Regional Water Quality Control Boards (RWQCBs). 

Once Environmental Health determines that site assessment is adequate, a corrective action plan, designed to mitigate the harmful effects of the release, will be requested when necessary. The corrective action plan may be included with the site assessment report; however, where Environmental Health staff does not agree that the site assessment is complete or that the corrective action plan adequately addresses the site's remedial requirements, a revised site assessment report or a revised remedial action plan will be requested. 

The Local Oversight Cleanup Program offers exceptional response time for the review of submitted reports and plans, 48 hours or less for the on-site presence of County oversight staff during assessment and remedial operations, and a convenient central Orange County business office location. Our staff is known for the efficient and timely manner in which cases are handled. The convenience of local agency oversight can help you avoid delays and achieve time objectives for site closure that can minimize your site cleanup expenses. 

For information regarding the submittal of work plans and reports, as well as assessment and remediation requirements for your site, please contact the Specialist assigned to your site as outlined below:

City Specialist (click on name to email) Phone (714)
Aliso Viejo Eugene Francisco 433-6254
Anaheim (Unincorporated) Karl Bewley 433-6264
Brea Eugene Francisco 433-6254
Buena Park Karl Bewley 433-6264
Costa Mesa Karl Bewley 433-6264
Coto De Caza Eugene Francisco 433-6254
Cypress Eugene Francisco 433-6254
Dana Point Karl Bewley 433-6264
Fountain Valley Karl Bewley 433-6264
Fullerton Karl Bewley 433-6264
Garden Grove Karl Bewley 433-6264
Huntington Beach Tamara Escobedo 433-6251
Irvine Eugene Francisco 433-6254
La Habra Eugene Francisco 433-6254
La Palma Eugene Francisco 433-6254
Laguna Beach Eugene Francisco 433-6254
Laguna Hills Eugene Francisco 433-6254
Laguna Niguel Eugene Francisco 433-6254
Laguna Woods Eugene Francisco 433-6254
Lake Forest Eugene Francisco 433-6254
Los Alamitos Eugene Francisco 433-6254
Midway City Karl Bewley 433-6264
Mission Viejo Eugene Francisco 433-6254
Newport Beach Eugene Francisco 433-6254
Orange Karl Bewley 433-6264
Placentia Karl Bewley 433-6264
Rancho Santa Margarita Eugene Francisco 433-6254
San Clemente Eugene Francisco 433-6254
San Juan Capistrano Eugene Francisco 433-6254
Santa Ana Eugene Francisco 433-6254
Seal Beach Eugene Francisco 433-6254
Stanton Karl Bewley 433-6264
Sunset Beach Eugene Francisco 433-6254
Tustin Eugene Francisco 433-6254
Villa Park Karl Bewley 433-6264
Westminster Karl Bewley 433-6264
Yorba Linda Eugene Francisco 433-6254


NOTE: The Specialist assigned to your site must be notified at least 48 hours prior to any soil or groundwater sampling activities so that they may be present at the site when such activities are being conducted.


For non-site specific information regarding the program, please contact Geniece Higgins, at 714-433-6260 or