On-Site Detention (OSD) servicing

 Routine maintenance prevents catastrophic failure and expensive repairs. 

• Every 6 Months:
  • Remove grates and screens to inspect internal walls and pits.
  • Remove accumulated sediment, sludge, debris, and litter.
  • Test float switches, pumps, and high-level alarms.

• Annually:
  • Inspect structural integrity for cracks, spalling, or leaks.
  • Check that OSD warning signage and plaques are secure and visible.
  • Clear gutters and downpipes to ensure water reaches the tank without blockages.

• Every 5 Years:
  • Perform a professional assessment to compare actual storage capacity with the original "Work As Executed" (WAE) plans. If more than 5% of volume is lost to siltation, it must be rectified.

Key Servicing Tasks

1. Debris Removal: Clearing organic matter like leaves and silt ensures the tank maintains its required Site Storage Requirement (SSR).
   
2. Orifice Plate Cleaning: The orifice plate (a metal plate with a specific-sized hole) regulates the Permissible Site Discharge (PSD). Any blockage here can cause the tank to overflow prematurely.
   
3. Pump Servicing: For systems that rely on pumps rather than gravity, checking for pump faults and ensuring discharge lines are clear is vital.
   
4. Jetting: High-pressure water jetting is often used to clean modular tank systems or hard-to-reach pipes.

Compliance and Documentation : Maintaining a service log is often a legal requirement. If your system discharges into a Sydney Water or local council network, you may need a formal service agreement registered on your property title.