Log in
What you need to know to stay safe
We do our best to stop wastewater (also called sewage) overflows before they happen. However, we can't always prevent them. Please stay clear of the area and stay safe.
When you see a sign like this, avoid the area.
Do what our warning signs say
Stay clear of wastewater overflows and obey our warning signs. It's the most important thing you can do to stay safe.
- Stay away from areas that are obviously affected by wastewater overflow.
- Don't swim or go fishing in an affected waterway.
- Don't drink water from an affected waterway.
- Pay special attention to children and pets.
- Keep away from machinery, hoses and other equipment we're using to clean up.
- Keep away from overflowing access chambers or maintenance holes.
Why overflows happen
Wastewater comes from sinks, showers and toilets. It's transported through our wastewater pipes for treatment. Overflows happen when the flow is more than the capacity of the pipe. This can happen wherever there are wastewater pipes: in bushland, in waterways, in parks, on the street or in your own backyard.
There are 2 main types of wastewater overflow:
Something in the pipe is causing a blockage
This is often called a dry weather overflow or choke.
A partial or complete blockage of a wastewater pipe will reduce its capacity. If the blockage is severe enough, wastewater will back up and eventually overflow.
Tree roots that find their way into the pipes are the most common cause of blockages. Blockages are also caused by things like wet wipes, facial tissues and hygiene products flushed in toilets (anything other than pee, poo and paper), and fats, oils and grease poured into sinks. All blockages normally contain a combination of these.
Wet weather flow is more than the wastewater pipe's capacity
This is often called a wet weather overflow.
Wastewater pipes are designed to allow for extra flow during wet weather. However, during very heavy rain this may not be enough. Extra water can enter the wastewater system through cracked pipes, faulty joints between pipes, around the lids of maintenance holes, and by direct connection of stormwater pipes.
Heavy rain is a common reason for wastewater overflows.
Stay outside barricades, well away from overflows, vehicles and heavy equipment.
Be aware of the risks
It's important to avoid areas impacted by a wastewater overflow and to keep children and pets away from them:
- Wastewater contains harmful microorganisms such as bacteria, viruses and protozoa. These can cause illnesses like gastroenteritis if you have direct contact with wastewater or surfaces contaminated by wastewater.
- There may be additional danger from heavy equipment and moving vehicles while we do essential repairs.
Wastewater that overflows into the environment can also harm sensitive species of flora and fauna.
We'll let you know when it's safe
You can be sure the area is safe when we remove our signs and barricades.
We use NATA-accredited labs to sample and test waterways. We test throughout the clean-up, and we continue cleaning until the lab results prove that the site has been effectively cleaned. This can take longer in bushland or natural areas. Our clean-up efforts are regulated by the NSW Environmental Protection Authority (EPA) and NSW Health.
Once we’ve physically cleaned the site, and contaminated surfaces are dry and exposed to sunlight, dangerous levels of microorganisms will be gone. The area will be safe to enjoy again.
When our warning signs are gone, you'll know it's safe.
How we manage overflows
We follow a strict process that's been agreed by regulators to manage wastewater overflow incidents:
1 The wastewater overflow is reported to us.
2 A technician goes to the site to verify wastewater overflow and assess the impact on both community safety and the environment.
3 We install containment immediately to stop the overflow from travelling further. We also put up signs and barricades to keep the community informed and safe.
4 The choke crew clears the blockage in the pipe using a high-pressure water jetter.
5 The clean-up crew removes all wastewater solids and contained liquids. It then cleans up the impacted area.
6 Signs and barricades won't be removed until we've completed important checks. The clean-up leader walks the site to verify the clean-up is complete. Then an environmental specialist takes water samples for laboratory assessment. Their lab sample confirms the site is back to its pre-overflow condition.
7 The wastewater overflow is resolved and the site is back to normal.
Find out more from the Sydney Water Wastewater Treatment Systems Pollution Incident Response Management Plan (PIRMP).