Sewerage Network Inspections

During seasonal wet weather, periods of heavy rain can increase the hydraulic loading on sewerage systems through inflow and infiltration.

Inflow is the discharge of rainwater and groundwater directly into the sewerage system through downpipes, low drainage points and backyard manholes.  Inflow has instant hydraulic impact on the capacity of the sewerage system and is the main cause of sewerage system overflows during periods of heavy rain. These inflows are typically caused by the deliberate redirection of water from yards, drains and downpipes into the sewerage system.

Infiltration is the lag effect of rain events where groundwater seeps into the sewerage system through damaged pipework underground.  This can continue slowly for days, sometimes weeks after the event at much lower volumes than inflows.

Council is undertaking an inspection program in Wulguru, Cluden and a small section of Annandale to identify inflows. The program allows Council to inspect properties in the identified sewerage catchments to identify point sources for inflow and potential infiltration into the sewerage system.

The program involves:

  • Safely smoke testing sections of the sewerage system within the defined catchments to provide a visual indicator of illegal, broken or damaged connections to Council’s sewerage system.
  • Physical inspection of any Council infrastructure within a property to determine potential maintenance and rectification requirements.
  • Physical inspection of external plumbing fixtures on each property for the purpose of identifying illegal or unauthorised connections that requires disconnection from Council sewerage system.

The program will commence between 16 March 2023 and 30 March 2023 and continue for a maximum of three (3) months from the date of commencement. Property owners or occupiers will be provided notice of entry a few days before their property is scheduled to be inspected.

Maps to showcase where the testing will be occurring can be found below: