Sometimes. In Sydney, building over a sewer pipe, or close enough to affect it, may be allowed if the asset owner approves the proposal and the design protects the pipe, structural loads and maintenance access. Approval is not automatic.
What determines whether it is allowed?
The approval pathway and design constraints depend on:
- Ownership and asset type: Sydney Water assets, other authorities’ assets and private sanitary drainage have different requirements.
- Verified location: Records can be approximate. Confirm the pipe’s position, depth, size and type before designing footings.
- Sewer access requirements: Maintenance holes and other access points must remain accessible. Required clearances depend on the asset and site; there is no single distance for every property.
- Foundations and loads: Excavation, footings and building loads must not damage the sewer. A structural engineer may need to assess the pipe’s zone of influence and design foundations accordingly.
- Easements: An easement may indicate land reserved for infrastructure or access, but it does not by itself confirm whether building over a sewer pipe will be approved.
What should I do before finalising the design?
Confirm the sewer pipe location, owner and approval conditions before committing to plans or starting excavation.
- Obtain available sewer records from the relevant asset owner and utility information through Before You Dig Australia.
- Establish whether the pipe is a Sydney Water asset, another authority’s asset or private sanitary drainage.
- Arrange professional locating or further investigation if records are not sufficiently accurate. A licensed plumber can help investigate private drainage.
- Submit the design through the asset owner’s approval process. Work affecting Sydney Water assets may require Building Plan Approval through Sydney Water Tap in and, depending on the proposal, assessment by a Water Servicing Coordinator.
- Have a structural engineer address relevant foundation loads, the zone of influence and access constraints.
- Incorporate all sewer protection requirements and obtain the asset owner’s approval before construction.
Do not excavate blindly or open, alter or relocate sewer pipework yourself. Concealed services may not be exactly where plans show, and damaged sewers can expose people to wastewater. Stop work if a pipe is exposed or damaged, keep people away and contact the asset owner and an appropriately licensed professional.
Our licensed Sydney plumbing team can help locate private drainage and identify which approval pathway applies before you finalise the extension design.