Blocked drains in Canberra are rarely just a blockage. In the pre-1980 suburbs the sewer under the yard is earthenware laid in short lengths with rigid joints, the ground it sits in is reactive clay that moves with every wet winter and dry summer, and above it stand the mature street trees the city is known for. Put those together and you get a sewer that cracks, lets roots in and blocks again every few months until the crack is dealt with. This page covers why drains block here, how they are cleared and diagnosed, the repair options, stormwater, and the line between what Icon Water owns and what you own.
Reactive clay and earthenware sewers
Most of Canberra sits on reactive clay. It swells when it is wet and shrinks when it dries, and across a year of frosty winters and dry summers the ground under a block can move enough to shift a rigid pipe. Earthenware sewer pipe, standard in the ex-govie homes of Ainslie, Dickson, Narrabundah and Griffith, the 1960s and 70s brick veneers of Curtin, Lyons, Hughes and Weston, the Belconnen suburbs of Macquarie, Hawker and Kaleen, and the earliest parts of Kambah and Wanniassa, was laid in short lengths with joints that cannot flex. The clay moves, the joint cracks or the pipe drops out of line, and from then on moisture leaks into the soil around it. Rebuilt homes in Duffy and Chapman after the 2003 bushfires, and the new homes on former Mr Fluffy blocks in Woden and Belconnen, often have new PVC drains inside the boundary connected to an original earthenware line that was never replaced.
Tree roots: plane trees, elms, eucalypts and poplars
Roots do not break a sound pipe. They find the moisture escaping from a cracked joint and follow it in, first as fine hairs, then as a mat that catches paper, wipes and grease until the line stops. The plane trees along inner north streets, the elms and poplars of the inner south, and the eucalypts on almost every large block in Kambah, Fadden and Monash are all capable of it, and a big tree can reach a sewer well beyond its canopy. Cutting the roots with a jetter clears the drain. Sealing the joint they came through is what stops them coming back.
Who owns what: Icon Water and the property owner
Icon Water owns the sewer main, usually running along the rear or side of the block or under the street, and the water main and meter. The owner owns the sewer line from the house to the point where it connects to the main, including the overflow relief gully in the yard, the inspection shafts and any sewer pit on the block. A blockage or crack in that line is the owner’s to clear and repair with a plumber licensed by Access Canberra. A blockage in the main, a surcharging manhole or a fault at the connection point is reported to Icon Water. When the CCTV inspection shows the fault is beyond the connection, you are told so rather than quoted for work that is not yours to pay for. In Queanbeyan, Karabar, Jerrabomberra and Googong the utility is Queanbeyan-Palerang Regional Council and the licence comes from NSW Fair Trading.
Clearing the blockage: jetting and CCTV
A high-pressure water jetter clears roots, grease, silt and foreign objects and scours the pipe wall, which a hand cable cannot do. Once the line is flowing, a CCTV camera is pushed through it and you see what caused the blockage, where it is and how deep, with the location marked on the surface of your block. For a first-time blockage caused by wipes or a toy, clearing may be all that is needed and you are told that. For a recurring blockage or any earthenware line, the camera footage is what separates a diagnosis from a guess, and it is kept for you and your insurer.
Repair options: relining or replacement
Where the pipe is cracked but still in line, relining is usually the answer. A resin-impregnated liner is drawn into the existing pipe and cured in place, forming a new smooth, jointless pipe inside the old one that roots cannot enter. It is done through existing access points, so gardens, driveways, paths and slab floors stay intact, which matters on the tight blocks of Braddon and Kingston as much as on a landscaped yard in Chisholm. Where a section has collapsed, dropped so far the liner cannot pass, or been crushed by a tree, that section is excavated and replaced with PVC and the rest relined if needed. Both options are quoted in writing before any work starts, and neither is pushed on a drain that only needed clearing.
Stormwater, sewer pits and overflow gullies
Canberra runs a separate stormwater system. Downpipes, surface grates, agricultural drains and the stormwater line to the street carry rain, not sewage, and they block with leaves, silt and roots in the same way. Summer afternoon storms overload them, and on sloping blocks in Fadden, Hawker, Hughes and the hills of Kambah the water runs into the garage, carport or lowest room. Jetting and camera inspection work on stormwater just as they do on sewers, and a crushed or root-blocked section can be relined or replaced before the next storm. Sewer pits and pump stations on low blocks that cannot drain by gravity, and the overflow relief gully that every Canberra house has in the yard, are checked at the same visit, because a gully that has been buried, paved over or capped cannot do its job of releasing a backup outside instead of into the shower.
Before the sewer backs up
The early signs are a toilet that gurgles when the bath drains, more than one fixture slow at once, a patch of unusually green or sunken lawn over the sewer line, or a smell around the outside drains. If sewage is already coming up through a floor waste or the gully, stop using water in the house and call the 24 hour plumber. If it is a single slow basin, a plunger is fine. Keep drain chemicals out of it; they do nothing to roots and make the line hazardous for whoever clears it. For homes with earthenware sewers, a camera inspection as part of plumbing maintenance every couple of years shows what is coming before it arrives in the laundry. Toilet repairs covers faults at the fixture itself.
What is included
- High-pressure water jetting to clear blockages, tree roots and grease from sewer and stormwater lines
- CCTV camera inspection to show you the cause and the exact location of any crack, break or root entry
- Pipe relining to seal cracked earthenware sewers without digging up the yard or driveway
- Excavation and replacement of collapsed sections where relining is not possible
- Clearing and repair of stormwater drains, surface grates, downpipes and sewer pits
- Advice on who is responsible when the fault is on the Icon Water side of the connection point
- Written report and recording from the camera inspection for your records or insurer
Signs you should call now
- Sewage or grey water coming up through a shower, floor waste or laundry trough
- The overflow relief gully in the yard is overflowing or smells strongly
- Toilets gurgling when a basin or bath drains, or the toilet water level rising and falling
- More than one drain in the house slow at the same time
- A patch of unusually green lawn or a damp, sunken area over the sewer line
- Water pooling in the garage, carport or downstairs room every time it storms
- Sewer smells inside the house or around the outside drains
Sewage inside the house is a health issue
Keep children and pets away from any area where sewage has surfaced, wear gloves if you have to touch anything, and do not use bleach or drain chemicals on a blocked sewer because they do nothing for roots and make the water hazardous for the plumber. Stop using water in the house until the line is clear.
Frequently asked questions
Why do Canberra sewers crack so often?
Much of Canberra sits on reactive clay that swells when wet and shrinks in drought. That movement pulls on rigid pipe joints, and the earthenware sewers laid in pre-1980 suburbs such as Ainslie, Curtin, Kambah and Macquarie crack at the joints or drop out of line. Once there is a crack, moisture escapes into the soil and tree roots follow it in. The result is a sewer that blocks every few months until it is properly repaired.
Which trees cause the most sewer problems?
Mature street and garden trees planted when the suburbs were built: plane trees along inner north streets, elms and poplars in the inner south, and eucalypts almost everywhere, including the big blocks of Kambah and Wanniassa. Roots seek the moisture at a cracked joint, enter as fine hairs and grow into a mat that catches paper and waste. Cutting the roots clears the blockage; sealing the crack by relining is what stops them returning.
Who is responsible for the sewer, me or Icon Water?
Icon Water owns the sewer main and the water main in the street. The property owner owns the sewer line from the house to the connection point with the main, including the overflow relief gully and any inspection shafts on the block. A blockage in your line is yours to clear and repair with a licensed plumber; a blockage or collapse in the main, or a fault at the connection, is reported to Icon Water. In Queanbeyan the utility is Queanbeyan-Palerang Regional Council.
What is pipe relining and does it work on earthenware?
Relining inserts a resin-soaked liner into the existing pipe and cures it in place, forming a new smooth pipe inside the old one. It seals cracks and root entry points without trenching through gardens, driveways or slab floors, and it works well on cracked earthenware sewers where the pipe is still in line. Where a section has collapsed or dropped so far that a liner cannot pass, that section is excavated and replaced first.
Why does my garage flood when it storms?
Canberra has a separate stormwater system, and on sloping blocks in suburbs like Fadden, Hawker and Hughes the surface grates and downpipe lines fill with leaves, silt and roots. In a summer afternoon storm the water has nowhere to go and runs into the garage or the lowest room. Jetting the stormwater line clear and inspecting it with a camera usually finds a crushed or root-blocked section that can be repaired before the next storm.
Is a CCTV inspection really necessary?
For a first-time blockage caused by something obvious, such as wipes or a toy, clearing the drain is often enough. For a recurring blockage, or any home in a pre-1980 suburb with earthenware pipes, the camera is what turns guesswork into a diagnosis. It shows the cause, the depth and the exact location on the block, so any repair is quoted for that section only, and you have footage to keep.
Can I put drain cleaner down a blocked sewer?
It is not recommended. Chemical drain cleaners do nothing to tree roots or a collapsed pipe, they sit in the blocked line as a hazard for whoever clears it, and they can damage older pipe. A plunger on a single slow basin is fine. If more than one fixture is slow, or anything is coming up through a floor waste or the overflow gully, the problem is in the sewer line and needs a jetter and a camera.
