Blocked Drains Sydney: Why It Keeps Blocking, and the Fix

A drain that blocks once is a nuisance. A drain that blocks every few months is telling you something, and pouring more chemicals down it will not make it listen. This page explains why Sydney drains keep blocking, what actually fixes them, what a proper clear includes, and what it costs. Read it before you call anyone, including us.

Overflowing now? Skip the reading: 1300 301 354 or book online. You get an arrival window on the phone and a fixed price before any work starts. $0 call-out fee.

Stop the overflow first

• Stop using water in the house. Every flush, shower or load of washing adds to the backup.
• If sewage is coming up through a floor waste or outdoor gully, keep people and pets away from it and turn off any appliance that drains into it.
• Do not pour anything down the drain. Not caustic soda, not “drain cleaner”, not boiling water into a toilet. Below is why.
• Find your overflow relief gully (the grated drain outside, usually near a bathroom or laundry). If it is overflowing, the block is in the main sewer line, not a single fixture, and it needs a plumber, not a plunger.

9 reasons Sydney drains keep blocking, and the one fix that stops it coming back

1. Tree roots. The number one cause in Sydney’s older suburbs. Roots find a hairline joint in an earthenware or old PVC pipe and grow into a net that catches everything.
2. Cracked or collapsed earthenware pipe. Common in homes built before the 1980s. Ground movement and roots break the pipe, and the low spot collects waste.
3. Wipes. “Flushable” wipes do not break down. They mat together with fat and block the line.
4. Fat, oil and grease from the kitchen sink, which set hard in the pipe.
5. Hair and soap scum in showers and basins.
6. A belly (sag) in the pipe where the ground has settled, so waste sits instead of flowing.
7. Undersized or badly graded pipework from a past renovation.
8. Foreign objects: toys, sanitary items, cat litter, tampon applicators.
9. A blocked overflow gully or stormwater line pushing water back into the sewer line in heavy rain.

The one fix that stops it coming back: find the cause with a CCTV drain camera after the clear, and fix the cause. If it is roots or a broken pipe, that means relining or replacing the damaged section. Everything else is a temporary clear you will pay for again.

5 things people pour down a blocked drain that make it worse

1. Caustic soda or supermarket drain cleaner. It rarely reaches a deep block, it sits in the pipe, and it burns the plumber who then has to open the line. Some products also damage older pipes.
2. Boiling water into a toilet or PVC waste. It can crack the porcelain and soften PVC joints.
3. Bleach. Kills smell for an hour, does nothing to the block.
4. Acid-based cleaners. Dangerous when mixed with anything else already in the pipe.
5. More water, “to push it through”. That is how a slow drain becomes an overflow onto the floor.

Jet blast or snake? What a proper clear includes

An electric eel (drain snake) cuts a hole through the block. It is quick and it is fine for a one-off object or hair. A high-pressure water jetter scours the full diameter of the pipe, cutting roots and flushing fat and scale to the sewer. For recurring blocks and tree roots, jetting is the right tool; a snake just drills a hole through the roots that closes again in months. A proper clear includes: the clear itself, a flow test at every fixture, a CCTV camera inspection to find the cause, and a plain-English explanation of what was found with the footage if you want it.

CCTV drain camera: worth it?

If the drain has blocked more than once, yes. The camera shows whether it is roots, a break, a sag or an object, and exactly where. That turns “we might have to dig” into “the break is 4.2 metres from the gully at 900 deep”. It is the difference between a quote and a guess.

3 questions to ask before anyone digs

1. “Have you put a camera down it, and can I see the footage?”
2. “Can it be relined instead of dug up?” Relining fixes many root and crack problems from inside the pipe with no trench.
3. “What is the fixed price for the dig, the pipe and the reinstatement of the ground or paving?” All three, in writing.

Landlord or tenant: who pays?

If you rent in NSW, a blocked or broken toilet and a serious drainage problem are urgent repairs the landlord has to fix. The exception is a block caused by what a tenant put down the drain, which the landlord can pass on. A camera report settles that argument fairly: roots and broken pipes are the property’s problem, wipes and cooking fat are usage. Either way the drain gets cleared first and the paperwork sorts itself out afterwards.

Drain callout fee, revealed

$0 call-out fee. We give you a fixed price to clear the drain before we start, and a separate fixed price for a camera inspection if you want one. If the clear needs the jetter rather than the eel, we tell you before we start, not after. No hourly rate, no “it took longer than expected”.

Blocked again in a month? Why

Because the block was cleared and the cause was not found. A snake through a root mass, a partial jet, or no camera afterwards. If a drain we cleared blocks again inside the warranty period for the same cause, we come back under warranty. If it is roots in a broken pipe, we will have shown you that on camera and quoted the permanent fix.

Book a same-day drain clear: 1300 301 354 or book online. You get an arrival window on the phone and a fixed price before any work starts. $0 call-out fee.

Who you are dealing with

All Day Plumbing & Maintenance Pty Ltd is a Sydney plumbing company based in Seven Hills, run by a licensed plumber with 20 years on the tools. NSW Contractor Licence 339748C. Fully insured. Every job comes with an upfront price before we start, a $0 call-out fee and a warranty on the work. You can check any NSW plumbing licence, ours included, on the NSW Fair Trading licence check (search “verify licence NSW”).