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Non-Standard Septic Systems Operational Permit and Monitoring

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Sonoma County’s Septic Systems Operational Permit and Monitoring (OPR) program monitors septic systems with supplemental treatment including nonstandard experimental and alternative systems to ensure they are operating properly for the protection of public and environmental health.

The program is necessary to comply with California’s Water Quality Control Policy for Siting, Design, Operation, and Maintenance of Onsite Wastewater Treatment Systems (State OWTS Policy). Supplemental treatment can be part of the septic system design or a separate pretreatment unit.

Permit Sonoma administers the county’s OPR program pursuant to the county’s Onsite Wastewater Treatment System Regulations and Technical Standards (OWTS manual), Sonoma County Code Sections 24-33 and 24-34, and in accordance with the State Water Resources Control Board requirements.


The California State Water Resources Control Board, through Regional Water Quality Control Boards, regulates septic systems and delegates permitting authority to local agencies, such as Sonoma County, to issue septic permits in accordance with the local agency’s regulations. Historically, Regional Water Quality Control Boards required Sonoma County to adhere to regional Basin Plans as part of the county’s septic permitting program. Regional Basin Plans required Sonoma County to inspect and monitor all non-standard septic systems and any septic system that incorporated supplemental treatment. To comply with the Basin Plan requirements, Sonoma County created the OPR program.  The county’s OPR program allows property owners more options regarding septic system types where they would otherwise not have been allowed.  This means more development potential for homes and business was allowed throughout the county where the development potential would otherwise have been severely limited.

The State OWTS Policy is now in effect and supersedes older regional Basin Plan requirements. The county’s OPR program has been updated to meet the minimum requirements of the State OWTS Policy.  Property owners with septic systems utilizing supplemental treatment are required to obtain OPR permits.

Permit Sonoma Roles and Responsibilities

Permit Sonoma staff facilitates the OPR application process.  Property owners installing a septic system utilizing supplemental treatment must apply for an OPR permit prior to final approval of the septic system. As part of the OPR permit application, property owners must submit a notarized OPR permit easement agreement which gets recorded on the property.  The easement agreement authorizes Permit Sonoma staff to enter the property and access various components of the septic system to perform periodic monitoring inspections required under the State OWTS Policy.

Permit Sonoma staff administers the OPR program. In addition to the periodic inspections noted above, Permit Sonoma staff communicates with property owners at various times of the year to notify them of the following OPR program responsibilities:

  • Schedule periodic monitoring inspections.
  • Comply with applicable correction notices.
  • Request biannual self-monitoring data.
  • Request payment of applicable fees as part of the annual OPR permit renewal process.

Property Owner Roles and Responsibilities

The property owner’s role and responsibility in the OPR program is to properly maintain and operate their septic system and to comply with applicable OPR permit requirements which include but are not limited to:

  • Maintaining their septic system components in good working condition including pumping septic tanks as needed, ensuring all components and dispersal areas are accessible and clear of excessive vegetation, and adhering to all applicable OPR permit conditions.
  • Performing biannual self-monitoring inspections and reporting results to Permit Sonoma.
  • Renewing OPR permits and pay applicable fees annually.
  • Ensuring a qualified Service Provider is performing the manufacturer’s required routine inspections and maintenance activities for pretreatment units.
  • Allowing Permit Sonoma staff to access all septic system components to perform required periodic monitoring inspections.
  • Complying with any applicable correction notices issued by Permit Sonoma staff.
  • Performing necessary repairs.

Prior to every March and October, Permit Sonoma sends property owners and/or Service Providers self-monitoring forms with pre-populated contact information and septic system information.  Property owners are responsible to perform self-monitoring inspections of their septic system in March and October of every year.  A Service Provider may perform the self-monitoring inspection and submit the results to Permit Sonoma on behalf of the property owner.

Every May, Permit Sonoma sends property owners notices to renew OPR permits and pay applicable fees by June 30 of every year. Fees are assessed based on the most current fee schedule adopted by the Board of Supervisors and fund the county’s OPR program. Property owners that do not pay annual fees on time are subject to late fees and additional penalties.

Property owners should verify or correct the contact information of record and provide a current email address. Any use of email addresses will be for official county business only such as notifications about the county’s OPR program.

Property owners with septic system that utilize pretreatment units are required to have a qualified Service Provider inspect, monitor, and maintain the pretreatment unit for the life of the septic system. A “Service Provider” is a California Registered Civil Engineer, Registered Environmental Health Specialist, or any person who is licensed as a "Certified Onsite Wastewater System Inspector" or other equivalent license by passing a state or nationally accredited onsite wastewater exam, capable of operating, monitoring, and maintaining an OWTS (for example, NAWT and/or a proprietary unit certification).


Systems in the program have recorded easement agreements to allow the associates and employees of Permit Sonoma onto the properties to monitor and test the non-standard OWTS. In an effort to streamline our inspection processes and improve communication with system owners/operators, we have increased and reassigned staff for residential and commercial systems in the Water Resources & Engineering Division.

Self Monitoring

Important Dates

Monitor twice a year during the following months using the pre-populated form emailed to you by Permit Sonoma.

March – Wet Season

Use the pre-populated form emailed to you by Permit Sonoma. Form must be completed by owner and received by Permit Sonoma before the end of March.

If you do not receive a form by mid-March, contact Well & Septic staff at (707) 565-2658 or email at End of March deadline still applies.

Instructions for Filling Out Form:
WLS-014 How to Monitor a Non-Standard Septic System

October – Dry Season

Use the pre-populated form emailed to you by Permit Sonoma. Form must be completed by owner and received by Permit Sonoma before the end of October.

If you do not receive a form by mid-October, contact Well & Septic staff at (707) 565-2658 or email at End of October deadline still applies.

Instructions for Filling Out Form:
WLS-014 How to Monitor a Non-Standard Septic System

Assistance with Monitoring and Maintenance

Monitoring and Maintenance Contractors

We strongly support having a contractor you trust and call if problems. It’s very important that you list all maintenance done (and any repairs that don’t require a permit) on your forms. If a contractor is submitting forms on your behalf, you are responsible for having them address any issues that need attention.

Know What You Have

Septic system permit information is available online by searching for address or parcel number via our Permit History Search. There may be other septic system documents also available (by address and parcel number) to be viewed in-person at our office by contacting our Records Counter staff and perhaps your consultant. You should ask for the main file as well as the OPR file.

Once you have acquired the records/documents, if you need assistance interpreting them, you can contact Well & Septic staff. You may also contact the consultant/designer.

Reduced Annual Fee Incentive Program

As an incentive for property owners to maintain their non-standard septic systems in good working order, Permit Sonoma has implemented a variable frequency inspection program which offers a Reduced Annual Fee Permit (RAFP). The RAFP is offered to property owners whose septic systems have at least a two consecutive year track record of acceptable operation. Learn more about the RAFP program.

Compliance – Get “On–Track Early-On”

To get on-track (and working toward a reduced annual fee permit, see WLS-016) we suggest:

  • Perform Biannual Self Monitoring
  • Obtain plan of record from County
  • Submit complete forms
  • Document all maintenance/repairs
  • Address items of concern mentioned in our inspection letters (necessary for reduced fee)
  • Instruct the County re: changes to phone or contact name and/or access onto the property and importantly to the SYSTEM AREA
  • Refer to instructional information
  • “Ask Questions"