Problems faced throughout the Northern Beaches and Sydney.

Blocked Sewer FAQs

Impact of trees on pipes

Trees play an important role in maintaining the environment and preserving the natural beauty of your property . However, if trees and plants are planted in the wrong place, their roots can find their way into wastewater pipes and cause sewage overflows. Tree roots cause about 80% (or about 14,000 overflows each year) of all dry weather sewage overflows. Sewage overflows can affect public health and the environment.

How do wastewater blockages happen?

When pipes become blocked, the sewage backs up and overflows from the pipe openings. This is called a sewage overflow. When a wastewater pipe becomes blocked, the sewage can overflow:

  • into your bathroom, laundry or toilet
  • on to public land such as parks or footpaths
  • into waterways and onto beaches.

Small pipes (100-225 mm) and pipes near the surface are most at risk from tree root invasion and blockage.

What are my responsibilities?

The wastewater network includes pipes managed by Sydney Water and private wastewater pipes that belong to property owners. You are responsible for all pipes that run through your property to the point where they connect to Sydney Water’s wastewater system. You are responsible for these pipes even if the connection point is outside your property.

What to do / How to go about it

Hiring a plumber?

If you are having plumbing or drainage work done, it’s important to always hire a licensed plumber and get a Certificate of Compliance once the work is finished. Here are some simple tips to follow before starting work.

Always hire a licensed plumber

It’s important to ensure you hire a plumber who has a valid and current license. By law, all tradespeople must display their license number for their services. You can check a plumber’s license on the NSW Fair Trading website at www.fairtrading.nsw.gov.au or call its customer service officers on 13 32 20.

Finding a licensed plumber

NSW Fair Trading issues licenses to plumbers who have the appropriate plumbing qualifications. Sydney Water can’t provide information about a plumber’s license.

The Master Plumber Association of NSW has a list of licensed plumbers on its website under findaplumber.com.au.

Ask for a Certificate of Compliance

A Certificate of Compliance is the plumber’s assurance that their work complies with the relevant plumbing codes and standards.

Only a licensed plumber can issue a Certificate of Compliance. Your plumber should give you a certificate once the work is finished.

They should also submit a copy of the certificate and Sewerage Service Diagram for any drainage work to Sydney Water for record.

Plumbing and drainage inspections

NSW Fair Trading is responsible for plumbing and drainage inspections. Your plumber should book an inspection for work on plumbing and drainage, recycled water systems or rainwater tanks. More information is available from the Fair Trading website.


If you are not happy with your plumbing and drainage work and can’t resolve the issue with your plumber, you can lodge a complaint with NSW Fair Trading.

Always hire a licensed plumber for drainage and plumbing work