Site Mitigation Programs
Local Oversight Program

Since April 1993, the State Water Resources Control Board has contracted with the County of Solano to provide regulatory oversight for the cleanup of leaking underground storage tanks (USTs) under local Oversight Program (LOP) contract. The programs services all the cities and unincorporated areas of Solano County and you can contact us at 707-784-6765. The LOP program staff are responsible for the following:
  • confirming the release
  • identifying and notifying Responsible Parties (RP) 
  • reviewing and approving preliminary site assessment workplans to determine the type and extent of soil and ground water contamination
  • overseeing assessment activities
  • reviewing assessment reports, quarterly reports, feasibility studies, risk appraisals/assessment, and corrective actions plans
  • issuing cleanup directives to the RPs
  • approving and overseeing cleanup operations
  • issuing no further action letter to RPs assessment and cleanup is adequate to protect public health and the environment
  • completing all records
The RP shall undertake the following activities to identify the type and extent of the contamination caused by a released hazardous Material, initiate  appropriate corrective action, and confirm that the corrective action has successfully mitigate the harmful effects of the release:  Corrective Action Requirements and Site Conceptual Model.

Well permits must be must be obtained prior to beginning exploratory borings and construction of wells. All borings and monitoring wells being installed and destroyed 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 licensed professional (PG, CEG, PE, or equivalent).

All work (including logs and well construction, reports, etc) shall be performed under supervision of a properly licensed professional in accordance with section 3065 of the Professional Standards & Code of Professional Conduct [Title 16, Division 29, Article 5].

LOP staff will evaluate site impact data provided by the licensed professional and discuss site cleanup goals considered protective of public health and the environment. Typically this evaluation includes identification of potential exposure pathways (air, soil, and, water) and the quantitative prediction of exposure levels for human and or environmental receptors. Guidance for cleanup goals are found in documents distributed by the California Regional Water Quality Boards for the San Francisco Bay and the Central Valley. The specialist assigned to your site must be notified at least 48 hours prior to any soil or ground water sampling activities so they may be present when such activities are being conducted please contact staff at (707) 784-6765

Site Cleanup Program

This program oversees the voluntary cleanup of contaminated property. Sections 101480 through 101490 of the California Health and Safety Code provide that a Responsible Party (RP) for a release site may request our oversight of a site investigation and any remediation necessary to mitigate the site. Oversight activities include any review required of site assessment and remediation workplans, review of required sampling operations, analysis of sampling data, and establishment of site cleanup criteria. RP can initiate oversight by submitting a written request for oversight. (Oversight Agreement). Once the signed agreement is received, the Environmental Health Services Division is required to notify the California Department of Toxic Substances Control and the applicable Regional Water Quality Control Board (RWQCB) to determine if these agencies have regulatory involvement with the site. If no concerns are raised by the State agencies, then a staff person of the Environmental Health Services Division - Hazardous Materials Section will oversee the investigation and remediation of the site on a direct billing basis. After determining that the RP has completed the site investigation and remediation necessary to protect human health and the environment then, Environmental Health Services Division - Hazardous Matherials Section will prepare a no further action "closure" letter stating that the investigation and remediation is complete.

File Review Process for Hazardous Materials Records.

You may contact this office at 707-784-6765 for an appointment. You may fax in a file review request on your letterhead listing addresses/locations for which you request to review with a prospective date and time for the review. These appointments are required to allow staff time pull any paper files, retrieve files for archives, obtain records for the California Environmental Reporting System (CERS) and to review paper files for confidential information that can not be legally release to the public. Please be advised, if you request copies of public records to be sent to you, pursuant the records clerk will respond to you within 10 days to let you know if the records are available, the cost of copying, and the cost for mailing/shipping. In January 2017, Cal EPA has launched a new web portal designed for environmental professionals and the public that contains information from multiple sources see
Regulated Site Portal and Cortese List Data Resource

Regulatory Links

UST Cleanup Fund Cost Guidelines

UST Case Closure Petition

Cleanup Fund Five Year Site Closure List

California Health and Safety Code Chapter 6.7 and Chapter 6.75

California Code of Regulations, Title 23

California Regional Water Quality Control Board, San Francisco Region UST Program

California Regional Water Quality Control Board, Central Valley Region

Underground Storage Tank Cleanup Fund

Department of Toxic Substances Control (DTSC)
Site Cleanup

Board for Geologists and Geophysicists

Contaminated Property Databases



Regulated Site Portal

Cleanup Criteria

Low Threat UST Case Closure

Environmental Screening Levels (ESLs)

California Human Health Screening Levels (CHHSLs)

A Compilation of Water Quality Goals


Oversight Agreement

Corrective Action Requirements

Site Conceptual Model Requirements

Closure Checklist

Low Threat UST Case Closure Checklist

Well/Soil Boring Permit Application  

Industrial Wastes into Septic systems

Motor Vehicle Fluids into Septic Systems

Small Business Guidance for Class V Injection Wells

Stormwater into Septic Systems and Dry Wells