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What you can do to prevent them
When household waste is flushed down toilets or poured into sinks, it can block drains and clog pipes. Wastewater can back up and overflow into homes, yards and local waterways.
Don't ignore these signs
- Your sinks, bath or toilet empty slowly.
- Your toilet isn't flushing properly or has overflowed.
- Your toilet or floor drain makes gurgling noises.
- Wastewater has overflowed from the drain or gully near your outside tap.
What causes wastewater blockages
Lots of things contribute to wastewater blockages. They include unflushable items in toilets, fats, oils and grease poured into sinks, tree roots, and even stormwater overloading our wastewater network during heavy rain. Every year, we spend as much as $27 million clearing up to 20,000 blockages from our wastewater system.
If the blocked pipes are on your property, you could be looking at a costly plumbing bill. Plus, wastewater blockages can create greater problems for you, the community and the environment.
Unflushable items
Blockages from unflushable items cause wastewater overflows. They're a health and environmental nightmare. Only flush the 3 Ps: pee, poo and toilet paper. Everything else? Put it in the bin.
- Non‑flushable* wet wipes contribute to 75% of wastewater blockages. Before flushing wet wipes, make sure the package displays the 'flushable' icon and the Australian Flushable Products Standard.
- Paper towels are designed for durability. They don't break down like toilet paper, and shouldn't be flushed.
- Hair doesn't dissolve in water. It floats, and snags easily on other unflushables.
- Tissues don't break down easily in water. When they're flushed, they build up.
- Cotton buds are made of materials that don't break down.
* Non-flushable wet wipes are products that don't comply with the Flushable Products Standard (AS/NZS 5328:2022).
Fats, oil and grease
Never pour fats, oils and grease down the drain. They cool and harden in wastewater pipes. They also combine with unflushable toilet waste to create fatbergs.
- Use strainers in kitchen sinks to prevent food waste getting into the pipes. Collect food scraps for compost or put them in the garbage bin. Some councils offer Food Organics and Garden Organics (FOGO) collections that let you add food waste to green bins along with garden waste.
- Put oily products like excess cooking oil and unused milk in sealed containers and put them in the garbage bin.
- You can also recycle cooking oil and motor oil at local Community Recycling Centres. They accept containers holding up to 20 litres.
Tree roots
Tree roots can enter small cracks in wastewater pipes to seek out nutrients. They continue to grow, taking up space and slowing drainage. This can cause a blockage.
Before planting trees on your property, know where your pipes are. Get a sewerage service diagram online at Sydney Water Tap in® so you can avoid planting trees within 6 metres of wastewater pipes. Some trees are more likely to cause problems to wastewater pipes. Your local nursery can advise on trees and their root systems.
If existing trees are a problem, a plumber can set up a regular maintenance plan for you.
Avoid planting these trees
| Botanical name | Common name |
|---|---|
| Acer sp. | Maple (mostly large) |
| Araucaria sp. | Norfolk Island Pine |
| Bambusa sp. | Bamboo |
| Brachychiton acerifolius | Illawarra Flame Tree |
| Callistemon sp. | Bottlebrush |
| 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 | Jacaranda |
| Lagerstroemia sp. | Crepe Myrtle |
| Liquidambar styraciflua | Liquidambar |
| Lophostemon confertus | Brush Box |
| Magnolia sp. | Magnolias (large) |
| Melaleuca | Paperbarks |
| Metrosideros excelsus | New Zealand Christmas Tree |
| Morus sp. | Mulberry (especially Black Mulberry) |
| Murraya paniculate | Orange Jasmine |
| Nerium oleander | Oleander |
| Persea americana | Avocado |
| Phoenix canariensis | Canary Island Date Palm |
| Pinus sp. | Pine |
| Platanus sp. | Plane trees |
| Populus sp. | Poplars |
| Prunus sp. | Apricot, Cherry, Peach, Plum |
| Quercus sp. | Oaks |
| Salix sp. | Willows |
| Sapium sebiferum | Chinese Tallow Tree |
| Schefflera actinophylla | Umbrella Tree |
| Schinus molle | Pepper Tree |
| Syzygium sp. | Lilly Pilly |
| Ulmus sp. | Elms (large) |
| Wisteria sp. | Wisterias |
Who pays to clear a blockage
Responsibility for removing wastewater blockages and repairing pipes depends on where our pipes connect to the affected property. If we authorise your investigations or repairs in our pipes, you or your licensed plumber may be eligible to claim for reimbursement.
If the blockage is in our pipes
We're responsible for the wastewater pipes that form our network. The blockage is probably in our pipes if:
- the overflow is visible beyond your property boundary, such as 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.
Our system connection diagrams will help you work out where your responsibilities end and ours begin. Call us on 13 20 90 24/7 to report the issue. We'll send a crew to investigate.
Have you already called a licensed plumber?
As a customer, you can claim for reasonable out-of-pocket expenses if you've paid a licensed plumber who found a blockage in our wastewater pipes, as long as they reported it to us to investigate. We'll send confirmation once we receive your customer claim form. It may take up to 8 weeks to process. Before you make a claim, make sure:
- the plumber calls us on 13 20 90 to get a job number – the job number must be included on the customer claim form
- 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.
A licensed plumber can submit a claim if they've incurred costs investigating a wastewater blockage that turns out to be in our pipes. As long as they've reported it to us to investigate and you haven't paid them yet, we may reimburse them.
Has overflow from our pipes damaged your property?
We'll arrange a clean-up and carry out any repairs required to stop the overflow. You'll have your own Customer Advocate to case-manage your complaint and support you through the insurance process. They'll also advise what they can do if you're not insured.
If the blockage is in your pipes
You are responsible for wastewater pipes from your property up to where they connect to the wastewater pipes that form our network. You'll need to contact a licensed plumber to clear the blockage.
The blockage is probably in your private pipes if:
- your neighbours aren't experiencing a blockage
- your drainage isn't shared with other properties
- there's no flooding in your local area
- you only experience an overflow when using water on your property.
Refer to our typical system connection diagrams to help you work out where your responsibilities end and ours begin.
Have your wastewater pipes collapsed on public land?
We may repair private collapsed wastewater pipes under a public footpath or road as a free service to residential customers. A licensed plumber must confirm that the only way to repair the fault is to excavate the road or footpath. Find out more from our Collapsed Private Services in Public Land Program: Guide for customers. Also, see section 8.6 of the Customer Contract.
