• Septic

Revised Onsite Waste Treatment Systems (OWTS) Manual

Board of Supervisors Consideration

The Sonoma County Board of Supervisors will be considering the revised onsite waste treatment systems (OWTS) manual at an upcoming meeting on May 22, 2018. If the Board approves the revision, the County will then submit a revised Local Area Management Program (LAMP) and OWTS Manual to the North Coast Regional Water Quality Control Board (NCRWQCB).

What is the OWTS Manual?

The Onsite Waste Treatment Systems (OWTS) Manual provides the policy, procedural and technical details governing individual onsite wastewater treatment systems (also referred to as septic systems). State law mandates the State Water Resources Control Board (State Water Board) adopt standards for regulation of onsite waste treatment systems (OWTS Policy). The OWTS Manual complies with the State Water Resources Control Board OWTS Policy Tier 2 Local Area Management Program (LAMP) requirements.

Revised OWTS Manual – April 27, 2018

The revised OWTS Manual that is being considered.

Entire Document (PDF: 7.84 MB)
Revised 2018 document provided in a single file.

Multiple File Version
Revised 2018 document divided into separate files for each section.

Strikeout-Underline-Annotated Version
Original 2016 version, with new 2018 changes added and the superseded/removed content struck out. The document is divided into separate files for each section.

Revised Local Area Management Program (LAMP) – April 27, 2018

The revised LAMP that is being considered.

Revised LAMP (PDF: 801 kB)

Current OWTS Manual – September 22, 2016

The OWTS Manual that is currently in effect and will be replaced.

Current Manual (PDF: 9.7 MB)

Revision Milestones

  • February 2018: After Sonoma County revised the OWTS Manual to meet State requirements, a subcommittee of the Land Use Advisory Panel reviewed the revisions.
  • February 22, 2018: Official public comment started on the publicly released Revised Manual.
  • March 30, 2018: Permit Sonoma hosted a public workshop to discuss the revised OWTS Manual.

Main Revisions

The main revisions to the manual include the measures below:

  • Permit Types. There are three types of permits: new, replacement and repair. New OWTS serve undeveloped properties. Replacement OWTS are for tank replacements and/or dispersal system replacements for developed sites (previously known as a voluntary repair). Repair OWTS allow for the relatively minor work: distribution box, valves, etc.
  • Voluntary Repairs. Previous voluntary repairs regulations would be eliminated. Typical voluntary repairs include replacing dispersal systems. A new or replacement dispersal system must meet a two (2) foot separation to groundwater, have adequate soil type and depth, and be designed by an appropriately licensed professional defined as qualified consultants in the State Business and Professions Code.
  • Classifications. Class I, II and III classifications would be replaced with references to either Code Compliant or Legal Non-Conforming systems.
  • Remodel/Rebuild. The remodel/rebuild and minor/major addition thresholds would remain the same. Definitions have been revised for clarity. Roof permits would no longer trigger OWTS review.
  • Financial Hardship. Financial hardship provision would exempt a client from the standards if a client can demonstrate hardship to the Director of Permit Sonoma. The hardship replacement permit could not serve as the basis for grant of any building permit.
  • Waiver. The North Coast Regional Water Quality Control Board adopted a revised Waiver of Waste Discharge Requirements that now includes OWTS that cannot meet the two (2) foot separation to groundwater. If the system cannot meet the two (2) foot separation standard, the client would have to apply to the NCRWQCB for its wavier. Local agencies cannot waive this standard according to the State’s OWTS Policy.

Contact Information

Contact Well & Septic by Phone
2550 Ventura Avenue
Santa Rosa, CA 95403
38.465225, -122.723293