Relining a Drain Costs About 8 Blockage Call-Outs. The Camera Decides Which You Need

Why a blocked drain keeps blocking: roots follow cracks

Three councils say the same thing about tree roots. Merri-bek City Council says roots are usually not the primary cause of pipe damage, that the problem typically occurs in old earthenware clay pipes, and that roots are extremely unlikely to damage an intact pipe. Woollahra Council says root blockages generally only happen if the pipe is already damaged or reaching the end of its life. Waverley Council says roots will not enter a private wastewater pipe that is intact and not leaking, and that many Waverley properties have old terracotta pipes with perished jointing seals.

That changes what clearing a blocked drain ($480) buys you. Merri-bek says that even after a plumber removes the roots, the pipe remains damaged and the roots can grow back in. Its advice for pipes that keep blocking is to repair them, replace them with PVC, or reline the old earthenware.

Older homes are more exposed. Water Corporation says a hairline fracture is all a root needs, and that homes over 15 years old are particularly at risk because they are less likely to have PVC sewer pipes. Gippsland Water says roots have been found up to 30 metres from their tree inside a pipe network.

Relining vs repeated clearing: the arithmetic

At Going Rate's prices, relining a damaged section of drain ($4,000) costs a bit over 8 times a single blocked-drain clear ($480). Eight clears still come in under the relining price, and the 9th takes the running total past it. Add a camera inspection ($530) to the relining side and the crossover moves to the 10th clear. A relining quote may already include the camera, so treat the camera-plus-relining figure as the cautious upper path.

No Australian source we found says how often a cracked house drain re-chokes after a root clear, so the payback depends on your own drain's history. The figures in this paragraph rest on our assumption that a house liner lasts as long as the 50-year minimum Sydney Water sets for linings in its own sewer pipes. That spec covers utility pipes, not house drains. On that assumption, relining costs about a sixth of one clear per year of liner life. Over the same 50 years, a clear every year would cost about six times as much as relining, a clear every 2 years about three times, a clear every 3 years about twice, and a clear every 5 years about 1.2 times. Relining comes out ahead whenever the drain would otherwise need clearing more often than about once every 6 years, or once every 5.3 years counting the camera.

A liner seals the crack, but it can still choke on what goes down the drain. Sydney Water says non-flushable wet wipes contribute to 75% of wastewater blockages. In 2018 Greg Ryan of the Water Services Association of Australia said there was no agreed way to assess whether a pipe-lining product was good other than trusting manufacturer claims, and no standard anywhere in the world to show a liner would last 50 or 60 years.

A CCTV drain inspection decides which job you need

A CCTV drain inspection ($530) costs about the same as one drain clear ($480) at Going Rate's prices, and about an eighth of the camera-plus-relining total. The footage shows whether the pipe is cracked, collapsed, or sound with a few roots at a joint.

The utilities do the same thing on their own pipes. Sydney Water's lining specification requires a CCTV inspection before any liner is installed. SA Water said in 2022 that after jet rodding its Adelaide sewer mains, crews run CCTV inspections to check the cleaning and the structural integrity of the pipe, and that they use root saws to break down roots.

The camera can also show that no big job is needed. In 2010 Sydney Water's Michael Charlton told City Hub that some older earthenware pipes don't need much changing at all because they are the right size and in good condition. If the footage shows a sound pipe, a one-off clear ($480) is the cheaper answer.

When digging up the drain is the answer

Going Rate has no price for excavating and replacing a house drain, and we found no sourced Australian figure for one, so this report gives none. Depth drives the job. SafeWork NSW classes a trench deeper than 1.5 metres as high-risk construction work that needs a Safe Work Method Statement and protection against collapse, such as shoring, benching or battering.

Some digs are not entirely yours. Sydney Water takes over the repair if excavation is needed at a point of connection more than 2.5 metres deep, though it will not reimburse digging down to 2.5 metres or work on the private pipe. It may also repair collapsed private pipes under a public footpath or road, if a licensed plumber confirms excavation is the only fix.

Victoria forces the issue on redevelopment. The state's plumbing practice note on property sewer drains says that when a site is redeveloped, a mortar-jointed clay drain other than a combined drain must be replaced back to the authority's sewer connection point. In Queensland, the QBCC lists pipe relining as minor work, which a licensed person must do but which needs no permit or Form 4. Any of these jobs starts with a licensed plumber ($1,100), and a relining job ($4,000) costs about three and a half times a typical plumbing job at Going Rate's prices.

Whose pipe is it? Where the utility's sewer ends

Each of these utilities draws the line near the boundary, and the private side is the owner's bill. Sydney Water owns the junction, but the owner must clear roots that enter it at the point of connection and pay for root damage to the junction. Yarra Valley Water's responsibility ends at the inspection opening or up to 1 metre from the boundary, whichever is less. Icon Water draws the line at the sewer tie on the lease boundary.

Hunter Water says the owner is responsible right up to the connection, including the boundary trap and inspection shaft. Water Corporation says blockages within property plumbing are the owner's, and blockages in the sewer main are its own. Gippsland Water says if a tree on your property blocks your drain or its sewer connection, you cover all costs of clearing and repair.

If the plumber finds the blockage is in the main, the utility carries it. SA Water processes plumbers' blockage claims made on a customer's behalf within 20 days of the invoice. A camera inspection ($530) is how the plumber shows which side of the line the problem sits on.

Insurance may not pay to fix the pipe

Suncorp excludes damage caused by tree roots, and says that if roots cause your pipes or drains to leak, the pipes themselves are not covered. Water that escapes from a root-blocked pipe may still be covered under its escape of liquid cover, which pays for the damage the water does but leaves the cracked pipe and the relining ($4,000) to you.

The ombudsman has backed Suncorp on root damage before. In 2021 AFCA upheld Suncorp's decline of a claim where tree roots had moved and lifted the ground around a property, according to Insurance News. That case was about ground movement, not a drain, but it turned on the same tree-root exclusion.

Council trees are no easy claim either. Woollahra Council says owners must maintain their own drains, and in many cases it would not consider compensation when council tree roots enter a private drain that was already defective.

How common are tree root blockages?

We found no national figure, and the utilities' own counts vary widely. Tree roots caused 17,392 of the 26,629 blockages in SA Water's sewer network in 2025-26, about 65% by our calculation. Morphett Vale had the most blockages in South Australia that year, with 675. These are counts for SA Water's own network, not for private house drains.

Unitywater, covering Moreton Bay, the Sunshine Coast and Noosa, attended 3,043 blockages in 2024-25, and roots caused 614 of them. It says roots account for 20% of known blockage causes. Gippsland Water says roots cause the majority of blockages and breaks in its water and sewer systems, and that it spends about $100,000 a year clearing root blockages alone. Sydney Water gives no root share and says non-flushable wet wipes contribute to 75% of wastewater blockages.

None of these counts tells you about your own drain. A drain that blocks again and again in an older house with clay pipes fits the pattern the councils describe, and a camera will show whether it does.

Common questions