The six most common causes of blocked drains in Sydney
Tree roots in old clay sewer lines
Most Sydney homes built before the 1980s have vitrified clay sewer pipes with rubber-ring joints. Roots from jacarandas, camphor laurels, figs and even hedges find the moisture at those joints, work through and grow into a mat that catches everything passing by. This is the single most common cause of recurring blockages we see across the Inner West, North Shore and the Lower Blue Mountains.
Wet wipes and 'flushable' products
Wipes do not break down like toilet paper. They snag on roots, pipe joints and bends, then trap fat and hair until the line stops. Sydney Water spends millions a year clearing them. Nothing but the three Ps — pee, poo and paper — should go down a toilet.
Fat, oil and grease from the kitchen
Hot cooking fat pours away as a liquid then cools and hardens on the inside of the pipe, narrowing it a little more with every wash-up. Scrape plates into the bin and pour cooled fat into a jar rather than the sink.
Hair and soap scum in bathroom wastes
Shower and basin wastes block gradually as hair binds with soap residue. A $5 drain screen prevents almost all of it.
Collapsed, cracked or misaligned pipes
Ground movement, heavy vehicles over a driveway, and simple age can crack or drop a section of pipe. Debris then piles up at the fault. If a drain re-blocks within a few months of being cleared, the pipe itself is usually the problem, not what went down it.
Storms and silt in stormwater lines
Leaves, roof grit and soil wash into downpipes and stormwater pits. After a big Sydney downpour, overflowing pits and water pooling near the house usually means the stormwater line is choked, not the sewer.
Early warning signs you have a blockage forming
A drain rarely blocks without notice. Catching it at the slow-draining stage costs a fraction of a full sewage overflow through the house.
- Water draining slowly from a sink, shower or bath
- Gurgling sounds from a toilet or floor waste when another fixture drains
- A sewage or damp smell in the yard, bathroom or near an overflow relief gully
- Toilet water rising higher than usual before it drains away
- Water pooling around a stormwater pit or against the house after rain
- More than one fixture backing up at the same time — this points to the main sewer line
How a blocked drain gets cleared properly
Locate the blockage
We open the inspection point and run a CCTV camera down the line so we can see exactly what is causing the blockage and how far along the pipe it sits — no guesswork, no unnecessary digging.
Clear it properly
A high-pressure water jetter cuts through roots, fat and debris and scours the pipe wall clean. An electric eel punches a hole through a blockage; jetting removes it.
Re-camera and fix the cause
We re-inspect the cleared line. If we find cracked joints or root entry points, we quote pipe relining so the same blockage does not come back next winter.
Preventative maintenance that actually works
- Fit drain screens to every shower, basin and laundry tub, and clear them weekly.
- Bin fat, oil and food scraps — never rinse them down the sink.
- Flush only toilet paper. Wipes, cotton buds, sanitary products and paper towel go in the bin.
- Clear gutters and stormwater pits twice a year, and again before storm season.
- Keep new trees and hedges well away from the sewer line, and know where that line runs.
- If you have clay pipes and mature trees, book a CCTV drain inspection every two to three years.
- Run hot water down kitchen and bathroom wastes for a minute each week to shift early build-up.
- Never use supermarket caustic drain cleaners on a full blockage — they sit in the pipe, damage it, and are dangerous for the plumber who opens the line.
When to call a plumber instead of trying to clear it yourself
A plunger and a drain snake will handle a single slow basin. Call a licensed plumber when more than one fixture is backing up, when sewage is surfacing at the overflow relief gully, when the same drain blocks repeatedly, or when a toilet overflows. Those are main line problems, and left alone they end in water damage to floors and cabinetry.
We clear blocked drains 24 hours a day across Greater Sydney and the Lower Blue Mountains, with upfront pricing approved by you before any work starts.