If your drain clears for a few weeks then backs up again in the same spot, the blockage is a symptom, not the problem. Something physical is sitting in that pipe, and until it is dealt with, the drain will keep filling back up. Clearing it again and again gets expensive fast. Here is what is usually going on and how we find it.
TL;DR
A drain that re-blocks in one place means tree roots, a bellied or collapsed section, or grease buildup. A CCTV camera shows which it is so you fix the real cause once. Relining repairs the pipe from the inside; a collapsed section may still need a dig. The pipe on your side of the sewer connection is the owner’s to fix.
What are the usual causes?
Tree roots. This is the big one in older suburbs. Central Coast Council’s sewer blockage fact sheet names tree roots infiltrating the pipes as a cause of sewer blockages, alongside things flushed or washed down that should not be. Roots chase the moisture and nutrients in a sewer pipe and push in through any small crack or joint. Once inside they grow into a mesh that catches everything that flows past. Cabling cuts them back, but they regrow, so the drain blocks again on a predictable cycle.
Some trees are worse than others. Hunter Water’s guide to planting near sewer pipes rates fig trees, willows, poplars and camphor laurel as an extreme risk, and large gums, jacarandas, casuarinas and pines as very high. If one of those is growing over the line, expect the roots to come back after every clear.
A bellied or collapsed section. Ground movement, poor bedding when the pipe was laid, or age can leave a low spot (a belly) where water and waste pool instead of flowing through. A partial collapse does the same thing. Solids settle in the dip and build up until the pipe chokes.
Grease and buildup. Fat, soap, food scraps and hair coat the inside of the pipe and narrow it over time, especially on a rough or already-damaged wall. Kitchen and laundry lines are the common offenders.
Why is a CCTV camera worth it?
For a one-off blockage, we just clear it. But when a drain keeps coming back, guessing is the expensive option. We push a CCTV drain camera through the line and watch on the screen exactly what is wrong and how far along the pipe it sits. That turns “it keeps blocking” into “there are roots at a joint 6 metres from the gully,” which is something you can fix properly instead of paying to clear it every few months. The footage is yours to keep, and it is handy before a property sale too. The CCTV drain inspection guide covers what the footage shows.
Clear it now, or fix it for good?
There are two jobs here, and they are not the same. Clearing gets the drain flowing again, usually with a high-pressure water jetter or an electric drain machine. That solves today’s problem. Fixing stops it coming back, and how we do that depends on what the camera shows.
| What the camera finds | How we fix it |
|---|---|
| Roots through a joint or crack | Cut them out, then reline or repair the damaged section so they cannot get back in |
| A bellied or collapsed section | Usually excavate and replace that length to restore the fall |
| Grease buildup | Jet the pipe wall clean; from there it is about what goes down the sink |
Relining or digging?
Pipe relining cures a cracked or root-affected pipe from the inside by curing a new liner against the old wall, so we do not trench your garden, driveway or paving. It works well on long, reasonably straight runs. A fully collapsed pipe, or damage right at a junction or under a slab, often still needs a dig and replace. We will not push relining where it will not last, and we will not dig up your yard if relining will do the job. Once we have seen the camera footage, we will tell you which one your drain needs and quote it as a fixed price.
Whose pipe is it, and who pays?
Usually yours. Central Coast Council’s sewer blockage fact sheet says residents maintain and repair all pipework from the point of connection on their property, while Council clears blockages in its own sewer. Council asks you to contact it first about a blockage or overflow in your property’s pipework, and it will tell you whether you need a plumber.
In Hunter Water’s area, if the sewer shaft on your block is clear, Hunter Water says to call a licensed plumber, at your own expense, to work out whether the blockage is in your drainage or in its network. If the plumber finds the problem is on Hunter Water’s side, Hunter Water arranges the work.
If a drain at your place keeps coming back, request a callback and we will camera it and tell you straight what is causing it. See our blocked drains service for more.