Septic Systems


Local Agency Management Program

Onsite Wastewater Treatment System (OWTS) Policy

The purpose of regulating the design, installation, and maintenance of onsite wastewater treatment systems (or, septic systems) is to:

  • Ensure that these systems provide a safe and reliable means of wastewater treatment and disposal for properties not served by a sewer system
  • Prevent the contamination of groundwater from improperly designed onsite wastewater treatment systems
  • Prevent the contamination of surface water from improperly designed onsite wastewater treatment systems
  • Prevent premature failure of onsite wastewater treatment systems

Program Services | Contact Us | Useful Information | Types of Systems


Program Services

  • Design review of new onsite wastewater treatment systems and Graywater Systems
  • Design review of repairs and modifications to existing on-site wastewater treatment systems
  • Installation inspections of onsite wastewater treatment systems
  • Maintain design records for properties using onsite wastewater treatment systems
  • Respond to citizen complaints of failing onsite wastewater treatment systems
  • Provide coordinated review with other agencies for projects that require CEQA (California Environmental Quality Act) or involve the use of onsite wastewater treatment systems
  • Provide review of discretionary land development projects that may involve DEH related permitting issues

Please note that a Project Issue Resolution Conference is available to applicants for discretionary land development projects processed through the County's Planning & Development Services:

Project Issue Resolution Conference

For land development projects processed through Planning & Development Services, a Project Issue Resolution (PIR) Conference is a meeting that includes an applicant, our Executive Management team, and County Project staff to discuss issues and identify solutions that were not able to be resolved with a County Project Manager due to interpretations of a code or other unique circumstances related to a project. The County is committed to helping customers navigate the land use permit process and ensuring customer satisfaction. The County recognizes land development can be complex and each project is unique. The goal of the PIR process is to help facilitate processing of each permit application in an efficient and timely manner by elevating technical project issues to our Executive Management team. For more information, please see PDS Page.  


Types of Systems

Currently, DEH is approving conventional system and supplemental treatment systems:

  • Septic tanks must have IAPMO approval and be approved for use by DEH
  • Leach lines can be constructed with either rock and pipe or other approved materials that would include plastic chambers
  • Horizontal seepage pits are restricted to sites with uniform soil conditions and average percolation rates not exceeding 30 minutes per inch  
  • Vertical seepage pits are restricted to coastal sedimentary basins that have degraded groundwater caused by salt water intrusion
  • Supplemental treatment systems must include percolation testing and a design from a licensed OWTS Professional
  • Any site with slopes that exceed 25% must include with the layout a slope stability report or statement from a licensed civil engineer or geologist

Useful Information

On-Site Wastewater Treatment System Layout Checklist


Frequently Asked Questions

Groundwater Separation Requirements

OWTS Professional List

Percolation Test Form

San Diego County Code: Onsite Wastewater System Ordinance

Septic Contractor List

Septic Pumpers List

Septic Pumper Truck Inventory Form

Septic Repair Authorization Form

Sewage Hauler Permit Application

EPA Homeowner's Guide to Septic Systems - (Spanish- Guía del dueño de hogar para sistemas sépticos)