OWTS Upgrade

For the following situations, the Onsite Wastewater Treatment System (OWTS) will need to meet Upgrade OWTS Standards:

  • Addition of one or more bedrooms beyond what the OWTS was legally permitted for
  • Addition of any habitable space beyond what the OWTS was legally permitted for:
    • Expansion beyond the one-time per parcel allowance of 500 square feet or any expansion of more than 500 square feet of habitable space
  • Addition of an Alternative Dwelling Unit (ADU)

The first step is to hire a knowledgeable qualified professional who needs to assess the following:

  1. If the septic tank meets the minimum capacity and construction requirements for the expanded usage and is functioning.
  2. Examine the dispersal field, for proper sizing, and if it is, determine if it is functioning properly. No visible evidence of recent failure and adequate area available for expansion (some standards have changed and since it is an upgrade, it needs to meet current standards).
  3. The proposed system for the building changes meets current setbacks (these may have changed, and some part of the system may need to be updated, so new setback standards will apply).

The information gained by the Qualified Professional will inform the next step, which is the Site Evaluation. The Site Evaluation will provide valuable information in determining the type of upgrade needed. The Site Evaluation information will be required when applying for an Installation Permit.

A Sewage Disposal Permit (hereafter, “Permit” or “Installation Permit” when clarification is required) is required for any person to upgrade an OWTS (or install, construct, enlarge, replace, modify, repair, abandon or destroy). This applies whether you are an owner, contractor, company or public agency. A Permit will only be issued to an owner or the pwner’s authorized representative (a qualified professional)..

Sewage Disposal Application: Installation Permit applications will only be accepted when determined to be complete. The application must include all the following:.

  1. Completed Application for Sewage Disposal Permit
  2. All items listed on the back of the application and the Sewage Disposal Application Checklist
  3. Complete System Design, including scaled Plot Plan, test results, study reports and all drawings as required per Site Evaluation Report
  4. Payment of all applicable fees
  5. Grading plan (when required by Environmental Health)
  6. Easement agreement or acknowledgement letter from neighbors if applicable
  7. Any additional information as required by Environmental Health (e.g., slope stability report or Geotechnical Report).

To schedule an in-person or online appointment, use our appointment scheduler: