Installer - On Site Sewage Facilities

Inspection Scheduling:

  1. A licensed installer should call Williamson County Engineer's office at 512.943.3330 to schedule an inspection for the next available business day.
  2. Representatives will ask for your installer number, license expiration date, and phone number, and will then confirm a scheduled inspection. 
    Note: Williamson County Engineer's office inspectors will contact installers to confirm appointment the morning of the inspection.
  3. If there will be an apprentice on-site, their contact information will also be needed.
  4. The installer is expected to be present at the job site with inspection equipment for surveying construction elevations.

Required System Inspections:
For most system types the permit application will allow for two inspections during critical phases. Additional inspections can be requested for an additional fee. Inspection schedules for different types of systems are listed below:

  • Standard/Leaching Chamber/Evapotranspiration Bed
    • 1ST: Tank/Pipe & Gravel
    • 2ND: Final/ Landscape
  • Aerobic Surface Application
    • 1ST: Open Tank and Lines
    • 2ND: Final/Electrical/Landscape
  • Aerobic Drip Irrigation
    • 1ST: Open Tank and Lines
    • 2ND: Final/Electrical/Landscape
  • Mound/Low Pressure Dose
    • 1ST: Tank/Mound Pad
    • 2ND: Final/Electrical/Landscape
  • Soil substitution
    • 1ST: Tank & Excavation
    • 2ND: Pipe & Gravel
    • 3RD: Final/Electrical/Landscape

Inspection Requirements
  • Tanks will need to be left open and full of clean water for 24 hours before the inspection.
  • At the time of first inspection filter fabric and backfill material will need to be on site.
  • For surface application systems, it may be possible to combine inspections.
  • You will need to contact this office and make special arrangements for drip irrigation systems that will be installed via plowing or trenching.
Low-Pressure Dose System Inspections
  • If gravel is installed for the mound system or pipe and gravel, open void spots or access to the excavation bottom will be need for levelness verification.
  • Installers may be requested to shovel dig random spots at the time of inspection.
  • Hole spacing will need to be counted for low pressure dose systems and mound installations, installer to contact this office to determine how they will be inspected if installed.
  • Mound pads will be probed to verify thickness and suitability of the pad.