Drainwise banner 02

What is inflow and infiltration

DrainWise Project

Show Sidebar

What is inflow and infiltration

Inflow and infiltration refers to rain water and ground water that enters the sewer (wastewater) system. 

Council has an Inflow and Infiltration programme to reduce the amount of rain water and ground water entering the sewer system on private property.

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

Check your property for illegal stormwater connections to the sewer.  Property owners need to make sure stormwater does not enter the sewer system from their property.

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

Contact your plumber or drainlayer for advice or talk to our DrainWise team. 

If you have a problem with flooding or ponding on your property during heavy rain - please tell us, fill in our flooding questionnaire

Managing our wastewater

Watch this video, it explains Gisborne's city's wastewater network


Last updated: