Certification of an Existing OWTS is required when proposing any construction on your property which involves increasing the potential wastewater volume (adding bedroom equivalents and/or plumbing fixture units), and/or expanding the building footprint on the property (for example, adding a barn, patio cover, or pool). There are three types of Certifications for existing OWTS, a full certification, a setback certification, or a mini certification.

Here are the application and supplemental materials you will need to submit to certify your existing OWTS:

  • Certification Application - fillable PDF (All Certifications) 
  • Zoning Clearance approved by Ventura County Planning (All Certifications)
  • Plot plan depicting all existing and proposed construction on the parcel in relation to the existing OWTS, including the septic tank, dispersal area, and 100% expansion area (All Certifications)
  • Floor plan depicting layout of proposed construction (All Certifications) 
  • Septic Tank Pump Report - PDF (Full Certifications) 
  • Bedroom Equivalent and Plumbing Fixture Unit Worksheet - PDF (Full Certifications)
  • Geotechnical Soils Report may be required (Full Certifications)

Please provide all required materials. An incomplete submittal will delay the processing and/or approval of your application. 


How do I know which type of Certification my project requires? 

There are three types of Certifications for existing OWTS, a full certification, a setback certification, or a mini certification:

Full Certifications are required when the applicant is proposing to increase the volume of home additionswaste water entering the system, for example, by adding bedroom equivalents and/or plumbing fixtures. Review of the information will determine if the system is adequately sized for the proposed addition. 

Setback Certifications are required when the applicant is proposing to expand the footprint of an existing structure and/or the addition of other structures that do not contain bedroom equivalents and/or plumbing fixtures. An on-site inspection is required to verify the location of an existing system and to insure the additional construction conforms to applicable setback requirements. 

Mini Certifications are similar to Setback Certifications. They are required when the property owner is proposing to expand the footprint of an existing structure and/or the addition of other structures that do not contain bedroom equivalents and/or plumbing fixtures. However, with a Mini Certification, the location of an existing system can be determined by reviewing Division OWTS records/as-built plot plans and may not require an on-site inspection.

Document imaged records for the majority of existing OWTS in the unincorporated County are available by searching the OWTS online records database. Click this link to view document imaged OWTS records:  Online Record Search

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