Inflow and infiltration

For any sewer issues that occur at your property please call Council's after hour service on (02) 6622 7022 at any time. 

What is inflow? 

Inflow is stormwater that enters directly into the sewer (wastewater) system. The cause is low gully traps, illegal downpipe connections to the sewer, cracked or damaged pipes.

What is infiltration?

Infiltration is stormwater that seeps into the ground and enters the sewer system through pipes and connections.  The cause is connection defects, cracks, and joints in the pipes. 

Problems caused by inflow and infiltration

During heavy rain, the sewer starts to fill with stormwater as a result of inflow and infiltration. Excess water in the sewerage system can cause it to back up and overflow sewage into homes and the environment.

We need your help

Property owners might not always be aware that rainwater from their property is entering the sewerage system. Previous residents may have connected a rainwater pipe illegally to the network.

What you can do to help

  • replace old leaking sewer pipes from your house to your property boundary
  • redirect your stormwater away from the gully trap
  • replace any broken or leaking gully traps

Inflow and infiltration fact sheets 

Factsheet 1 - Mullumbimby inflow & infiltration(PDF, 2MB)

Factsheet 2 - Mullumbimby inflow & infiltration(PDF, 5MB)