Wastewater blockages

How to deal with them

A wastewater blockage, or sewer choke, can occur when there's something inside a pipe that stops it working properly. They have common causes: tree roots that have found a way into the pipes, when someone puts something down the toilet that it's not designed for, such as wet wipes or other hygiene products, or by stormwater entering the wastewater network and overloading it during heavy rainfall.

Wastewater overflows and the community
If you see a wastewater (sewage) overflow, please avoid it for your own safety. Find out how to stay clear of wastewater overflows.

Trees and wastewater blockages

Tree roots are a common cause of damage to wastewater pipes. They can enter small cracks in your wastewater pipes to seek out nutrients and then continue to grow. As they grow, they take up more space and slow down your drainage. This can eventually cause a blockage.

Signs of a blockage can be:

  • slow drainage
  • gurgling noises in sanitary drains
  • odour overflows in your home and property.

Remember that flushing the wrong things down the toilet can also cause blockages.  The only things you should flush are the 3 Ps: pee, poo and toilet paper. While some brands of wet wipes might say they’re flushable, they aren't.

Before you plant trees on your property, find out where your wastewater pipes are. A sewerage service diagram will show you. You can get one online through Sydney Water Tap in. Try not to plant trees within 6 metres of wastewater pipes. Your local nursery can advise on trees and their root systems or check the list below for trees to avoid.

If your existing trees are a problem, ask a plumber to set up a regular maintenance plan for you.

Trees you should avoid planting

Tree species vary greatly in their ability to enter the wastewater system and cause damage. The trees listed below are likely to cause problems to your wastewater pipes. We recommend that you don't plant these species within 6 metres of a wastewater pipe.

Botanical name

Common name

Acer sp.

Maple (mostly large)

Araucaria sp.

Norfolk Island Pine

Bambusa sp.


Brachychiton Acerifolius

Illawarra Flame Tree

Callistemon sp.


Casuarina sp.

Casuarinas or She-Oaks (especially River Oak and Swamp Oak)

Celtis sp.

Nettle-tree and Hackberry

Chamaecyparis/Cupressus sp.

Cedar and Cypress

Cinnamomum Camphora

Camphor Laurel

 Erythrina sp.

Coral tree (large)

 Eucalyptus sp.

Gum trees (large)

 Ficus sp.

Figs (Moreton Bay Fig, Weeping Fig, Rubber Tree)

 Fraxinus sp.

Ashes (large)

 Jacaranda Mimosifolia


 Lagerstroemia sp.

Crepe Myrtle

 Liquidambar Styraciflua


 Lophostemon Confertus

Brush Box

 Magnolia sp.

Magnolias (large)



 Metrosideros Excelsus

New Zealand Christmas Tree

 Morus sp.

Mulberry (especially Black Mulberry)

 Murraya Paniculate

Orange Jasmine

 Nerium Oleander


 Persea Americana


 Phoenix Canariensis

Canary Island Date Palm

 Pinus sp.


 Platanus sp.

Plane trees

 Populus sp.


 Prunus sp.

Apricot, Cherry, Peach, Plum

 Quercus sp.


 Salix sp.


 Sapium Sebiferum

Chinese Tallow Tree

Schefflera Actinophylla

Umbrella Tree

 Schinus Molle

Pepper Tree

 Syzygium sp.

Lilly Pilly

 Ulmus sp.

Elms (large)

 Wisteria sp.



Who's responsible for what

What we're responsible for

Sydney Water is responsible for the wastewater pipes from our network up to the property connection point.

The blockage is likely to be in Sydney Water's pipes if:

  • the overflow is visible beyond your property boundary, for example, from a maintenance hole located on public land
  • your neighbours are experiencing the same problem
  • there's widespread flooding in your local area
  • you're experiencing a continuous overflow and you're not currently using water on your property.

If this is the case, please call us on 13 20 90 24/7 to report the issue. We'll send a crew to the site to investigate.

If your property’s been damaged by overflow from our pipes
We’ll talk to you to arrange a clean-up and carry out any repairs required. We can assist with alternative accommodation, and work with you and your insurer to process claims until your property is restored to its previous condition.

What property owners are responsible for

Property owners are responsible for the private wastewater pipes on their property up to and including where they connect to our pipes (the connection point). The blockage is likely to be in your private pipes if:

  • your neighbours aren't experiencing a blockage
  • your drainage isn't shared with other properties
  • there is no flooding in your local area
  • you're only experiencing an overflow when using water on your property.

If this is the case, please contact a licensed plumber to clear the blockage in your pipes.

Not sure if the blockage is in your private pipes or our network?
Please call us on 13 20 90 and we'll ask you some simple questions to identify the location of the blockage.

Claims for out-of-pocket expenses

You can claim for reasonable out-of-pocket expenses:

  • if you're a licensed plumber and you've found a blockage in our wastewater pipes
  • if you're a customer and you've paid a licensed plumber who found a blockage in our wastewater pipes.

What you need to know before you make a claim

Before you fill out the claim form, please ensure that:

  • the plumber calls us on 13 20 90 to get a job number – this number needs to be included on the form
  • you read our Claiming for wastewater blockages (525KB) guide
  • you have all invoices and supporting documentation ready to attach
  • you provide a timesheet or excavation details if the invoice doesn't give a detailed account of the work completed.

Need to make a claim?
Use our Wastewater blockage claim form (93KB)We'll send you confirmation once we receive your claim. It may take up to 8 weeks to process.

Road or footpath excavations

If your licensed plumber finds that your private wastewater pipes have collapsed under a public road or public footpath and we verify that the collapse can’t be repaired without excavating, we may be able to help with the repair at no cost to you through the Collapsed Private Service in Public Land Program  (conditions apply). Note that we can't reimburse you or your plumber for any plumbing costs related to this work.

Find out more from the Collapsed Private Services in Public Land Program: Guide for customers (256KB). You should also read section 8.2 of the Customer Contract (6MB).