25 May 2020

Who is responsible for a blocked sewer drain in Australia?

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If your only interaction with your neighbour is a polite nod of the head when putting the bins out, it can be difficult to know how to navigate the big, expensive conversations like who is responsible for the blocked sewer drain you both share.

We have put together a summary of the specific guidelines in Australia about who is responsible for shared sewer drains and any costs associated with their maintenance and repair.

How does it work?

The responsibility for a blocked sewer drain falls into two categories:

  1. The property owner/s
  2. The local water retailer

In a nutshell, water retailers are responsible for the water outside of your property, and you are responsible for the water inside your property boundary.

For many suburbs north of the Melbourne CBD, Yarra Valley Water is the water retailer. View the list of Melbourne water retailers here.

Each property that receives a sewer service from Yarra Valley Water has a connection to the sewer main.

The property owner is responsible for all the fittings and pipes inside the property to the connection point with the Yarra Valley Water pipes. The connection point is known as a ‘27A’ which is usually located near the property boundary.

Any pipes and fittings on the owner’s side of the Yarra Valley Water connection point (27A) including the boundary trap (BT) and the inspection shaft (IS) are the responsibility of the property owner. This means any repairs, replacement of maintenance costs associated with these pipes and fittings are the responsibility of the property owner.

Single house

Combined private plumbing


Yarra Valley Water responsibility ends at the I.S. or up to 1 metre from the property boundary (whichever is less).

Sewer connection points legend



What is a combined drain?

A combined sewerage drain is a privately owned sewerage pipe that collects sewage from multiple properties.  The sewage collected from each property is then disposed to Yarra Valley Water’s sewer main via a single connection.

Combined drains are the responsibility of multiple property owners. If a section of combined drain is found to be defective, the responsibility (and expenses) for maintenance rest with all affected property owners.


What should I do if I have a blockage?

Call a plumber. They have the equipment to identify where and what is causing your blocked drains, such as CCTV cameras, sonar pipe scanners, high pressure jets and much more. If the blockage is on your property, the plumber can clear the blockage and fix any damage. If the blockage is in the Yarra Valley Water pipes, they will fix the problem at no cost (and can even reimburse you for the cost of the plumber!).