You own the wastewater pipes on your property up to and including the point where they connect to Sydney Water’s system. Sydney Water owns everything from that point onwards.
The part almost everyone gets wrong is where that point sits. It is not your fence line. Sydney Water’s own guidance states that your wastewater system may extend beyond your property boundary, and that the point of connection may even be on another property.
Quick answer
- Your responsibility: every pipe on your side of the connection point, including the connection point itself
- Sydney Water’s: the network from that point onwards
- Call Sydney Water on 13 20 90 first if neighbours are affected, there is local flooding, or it overflows while nobody is using water
- If a plumber finds it is theirs, you can claim your costs back, but only if the plumber gets a job number at the time
The Boundary Rule, Properly Stated
Sydney Water’s position is that property owners own all wastewater pipes and fittings up to where they connect to the wastewater system, including the point of connection itself.
Three consequences follow, and they are the reason this question costs people money.
Your pipe can run outside your land. On plenty of Sydney properties, the private line continues under the footpath or the nature strip before it meets the main. That section is still yours.
Your connection point can be on someone else’s property. Common in older subdivisions, terraces and battleaxe blocks. It does not become their problem because it sits on their land.
Shared lines exist. Joint or party services, where one line serves several properties, are common in older parts of Sydney. Where one exists, the owners share responsibility for it, which makes a blockage a conversation with the neighbours as well as a plumbing job.
So the honest version of the rule is not “it stops at the fence”. It is “it stops where it meets their pipe, and you need to find out where that is”.
How to Find Your Connection Point: the Sewer Service Diagram
This is the most useful document a Sydney homeowner can get about their own drainage, and most people have never heard of it.
A sewer service diagram, also called a property sewerage diagram, shows the private wastewater pipes on your property and where they connect to Sydney Water’s system. Buildings and pipes are shown. Pools are not. You can apply for one through Sydney Water Tap in, or through a broker who will add their own fee on top.
What it tells you: the route your private line takes across the property, where the inspection openings and the boundary trap are, and where the point of connection sits. Older diagrams also carry notes intended for plumbers.
What it does not tell you: the condition of any of it. The diagram is a record of the drainage as it was at the time of inspection or installation, not a survey of what is there now. Work done since may not appear, and pipes are not always precisely where the drawing indicates.
Do not confuse it with a service location print. They are different documents. The sewer service diagram covers the private pipes on your property. A service location print shows where Sydney Water’s own pipes run and how close your building sits to them. If you are trying to work out whose blockage it is, the sewer service diagram is the one you want.
If you are buying an older property, ask for it. It costs very little, and it is the only cheap way to know what you are taking on.
The Boundary Trap, and Why It Matters Here
On many older Sydney properties there is a boundary trap near the front boundary: a water-sealed fitting between your private line and the main, originally installed to stop sewer gas travelling back from the network.
It matters for this question because it is usually the last accessible point on your side of the system, which makes it the place a plumber opens first to work out whether a blockage sits upstream or downstream of it.
The practical problem is finding it. Boundary trap caps disappear under turf, paving, mulch and garden beds over the decades, and a corroded lid sitting flush with a path looks like nothing at all. This is another reason to pull the sewer service diagram before anyone starts lifting pavers.
Homes built before about 1970 are the ones most likely to have one, and they are the same properties dealing with the clay lines and root intrusion common in older Sydney homes.
How to Tell Whose It Is Before You Call
Two minutes of checking decides which number you dial.
| Probably yours | Probably Sydney Water’s |
|---|---|
| Neighbours are unaffected | Neighbours have the same problem |
| Your drainage is not shared with other properties | Overflow is visible beyond your boundary, such as from a maintenance hole |
| No flooding in the local area | Widespread flooding locally |
| It only backs up when you use water | Continuous overflow while nobody is using water |
If the right-hand column fits, call Sydney Water on 13 20 90 before anyone else. The line is staffed around the clock, and the call costs nothing.
If the left-hand column fits, it is a licensed plumber’s job, and Sydney Water will tell you the same thing.
Still not sure whose it is?
Call R&G on 0461 330 531 and describe what is happening. If it sounds like Sydney Water’s, we will tell you to ring them first, because that call is free and ours is not. $0 call-out fee either way.
Proving It: Why the Camera Settles the Argument
The checklist above narrows it down. It does not prove anything, and when money is involved, you want proof.
A plumber establishes it in a specific order. The inspection opening or boundary trap is opened first, which immediately shows whether the blockage sits upstream or downstream of that point. If the answer is downstream, a camera is run to the fault, and its distance and depth are marked from the surface using the transmitter in the camera head.
That gives you a number rather than an opinion: the blockage is at 14 metres, at 900mm depth, which is past the connection point. That is the evidence Sydney Water works from, and it is what makes a claim straightforward rather than a negotiation. It is also what turns a guess into a priced drain repair if the fault turns out to be on your side.
If It Turns Out to Be Theirs, You Can Claim the Cost Back
This is the part worth knowing before you book anyone.
If a licensed plumber attends and finds the blockage is in Sydney Water’s pipes rather than yours, you can claim reasonable out-of-pocket costs back from Sydney Water.
The condition is procedural, and it is easy to miss. Your plumber has to contact Sydney Water and obtain a job number at the time of attending. Without that number, the claim does not proceed, and it cannot be fixed retrospectively.
So when you book, say this: if it turns out to be Sydney Water’s, please call them and get a job number before you leave. Keep every invoice, and expect a claim to take up to eight weeks.
One related point: where a repair at the connection point requires excavation deeper than 2.5 metres, Sydney Water takes the repair over.
The Water Supply Side Has a Different Rule
Worth including because people assume the two work the same way, and they do not.
On the drinking water side, Sydney Water may repair your water pipe free of charge between their water main and your meter, up to one metre inside your property boundary. Beyond that metre, and beyond the meter, it is yours.
That is a more generous position than the wastewater rule, and it catches people out in the opposite direction: they pay a plumber for something that would have been covered. If you leak on the street side of your meter, it is worth a call to Sydney Water before a call to anyone else.
What Not to Do While You Work It Out
Do not keep using water if anything is backing up indoors. Every litre has to go somewhere. If waste has reached a fixture you did not use, read what a toilet backing up into the shower means, and if it is already overflowing, sewage coming up the shower drain covers the next thirty minutes.
Do not let stormwater into your wastewater line. Sydney Water is explicit that rainwater and stormwater must not enter the wastewater system, and a cracked line taking in rain is treated as a defect to be repaired.
Do not dig looking for the connection point. Pull the diagram first. Digging on the strength of a guess is how a cheap diagnosis becomes an expensive one.
Frequently Asked Questions
Does my responsibility really extend past my fence?
It can. Sydney Water’s guidance states that a private wastewater system may extend beyond the property boundary and that the connection point may even sit on another property. Ownership follows the pipe to the connection point, not the title boundary.
How much does a sewer service diagram cost?
A small amount when you apply directly through Sydney Water. Brokers and conveyancers can obtain one for you and will add their own fee, so going direct is cheaper if you are not in the middle of a conveyance.
Who pays if the blockage is on a shared line?
Where a joint or party service runs to several properties, responsibility is shared between those owners. In practice that means agreeing a split before work starts, and getting the camera footage so everyone is looking at the same evidence rather than arguing from memory.
Can I call Sydney Water just to check?
Yes, and you should if any of the right-hand column applies. The faults line is free and staffed around the clock. If it is a private problem, they will tell you, and you have lost nothing but a few minutes.
My sewer service diagram does not match what is actually in the ground
That happens, particularly on properties that have been extended or re-plumbed. The diagram records the drainage at the time of inspection, not as it stands today. Where the two disagree, a camera with surface locating is what establishes the truth.
Find out whose pipe it is, with evidence.
We open the inspection point first and establish which side of the connection the blockage sits on before anything else happens. If it turns out to be Sydney Water’s, we get the job number so you can claim the cost back. $0 call-out fee, fixed price before any work starts, across the North Shore, the Hills and Western Sydney. See how we handle blocked drains across Sydney.
