Will drain cleaner from the supermarket fix a recurring blockage?

Usually not. Caustic drain cleaners can eat through a small soft blockage but do nothing to tree roots, collapsed pipes or heavy grease, and repeated use can damage older pipes and seals. If a blockage keeps returning, the cause needs to be found and cleared mechanically.

How do I know if tree roots are the cause?

Tell-tale signs are gurgling toilets, multiple drains slow at once, and blockages that return every few months, often worse in wet weather. The only way to confirm is a drain camera inspection to see the roots in the pipe.

Can I stop grease blockages myself?

Yes, largely. Never pour cooking fat or oil down the sink, wipe greasy pans with paper towel before washing, and run hot water through the kitchen drain after doing dishes. This prevents the fat setting hard inside the pipe.

Is a slow drain the same as a blocked drain?

A slow drain is an early warning that a blockage is forming. It is much easier and cheaper to clear at that stage than to wait until it is fully blocked and overflowing, so it is worth acting on a slow drain early.

How much does it cost to clear a recurring blockage in Sydney?

Clearing a blocked drain in Sydney is roughly $150 to $350 depending on severity and access, and a full drain camera inspection is around $200 to $400. Terry gives a fixed quote before starting any work.

Will drain cleaner from the supermarket fix a recurring blockage?

Usually not. Caustic drain cleaners can eat through a small soft blockage but do nothing to tree roots, collapsed pipes or heavy grease, and repeated use can damage older pipes and seals. If a blockage keeps returning, the cause needs to be found and cleared mechanically.

How do I know if tree roots are the cause?

Tell-tale signs are gurgling toilets, multiple drains slow at once, and blockages that return every few months, often worse in wet weather. The only way to confirm is a drain camera inspection to see the roots in the pipe.

Can I stop grease blockages myself?

Yes, largely. Never pour cooking fat or oil down the sink, wipe greasy pans with paper towel before washing, and run hot water through the kitchen drain after doing dishes. This prevents the fat setting hard inside the pipe.

Is a slow drain the same as a blocked drain?

A slow drain is an early warning that a blockage is forming. It is much easier and cheaper to clear at that stage than to wait until it is fully blocked and overflowing, so it is worth acting on a slow drain early.

How much does it cost to clear a recurring blockage in Sydney?

Clearing a blocked drain in Sydney is roughly $150 to $350 depending on severity and access, and a full drain camera inspection is around $200 to $400. Terry gives a fixed quote before starting any work.

Drains

Why does my drain keep blocking?

By Terry, licensed plumber (Lic L10959) · 25 June 2026 · 5 min read

Quick answer

A drain that keeps blocking usually has an underlying cause the plunger cannot fix: built-up grease and fat, hair and soap scum, tree roots pushing into pipe joints, flushed wipes, or old collapsed and misaligned pipes. Until that root cause is cleared and inspected, blockages will keep coming back.

Why does my drain keep blocking? - Terry's Plumbing, Berala

A one-off blockage is bad luck. A drain that blocks again and again is a symptom, and clearing it over and over with boiling water or a supermarket drain cleaner only treats the surface. To stop it for good you need to know what is actually causing it, and in most Sydney homes it comes down to a handful of usual suspects.

The most common repeat-blockage causes

Grease and fat down the kitchen sink. It goes down as a warm liquid, then cools and sets hard inside the pipe like candle wax, catching everything after it.
Hair and soap scum in the bathroom. Hair knots together, soap and shampoo residue binds it into a solid plug in the trap and waste pipe.
Flushed wipes, cotton buds and sanitary items. Even so called flushable wipes do not break down, and they snag on any small imperfection in the pipe.
Tree roots. In older Berala and Western Sydney streets with mature trees, fine roots find their way into pipe joints seeking water, then grow into a dense mat.
Old, cracked, sagging or misaligned pipes. Earthenware and early PVC pipes shift over decades, creating bellies where waste pools and catches.

Why it keeps coming back

If a plunger or a chemical clears it for a week or two and then it returns, the blockage was never fully removed. A partial clear just punches a hole through the middle of the build-up. The narrowed pipe fills straight back up. Tree roots and pipe damage will never respond to anything you pour down the sink, because the problem is in the pipe wall itself.

Terry has been clearing drains around Berala, Auburn, Lidcombe and the inner west since 1986, and the pattern is nearly always the same: the homeowner has tried everything from the hardware store, and the drain is still slow. The honest fix is to see inside the pipe.

How Terry actually diagnoses it

Rather than guess, Terry runs a drain camera down the line to find the exact spot and cause. That takes the guesswork out. From there he can clear it properly with an electric drain machine or high pressure water jetter, and if tree roots or a broken section are the culprit he can talk you through relining or repair so it does not simply grow back.

A quick DIY prevention checklist that genuinely helps:

Scrape plates and tip cooking fat in the bin, never down the sink.
Fit cheap hair catchers over shower and basin wastes.
Only ever flush the three Ps: pee, poo and paper.
Run hot water through the kitchen sink after washing up.

If your drain keeps blocking despite doing all of that, the cause is inside the pipe and needs a proper look. Call Terry on 0415 274 542 for a straight answer and a fixed quote before any work starts.

Frequently asked questions

Will drain cleaner from the supermarket fix a recurring blockage?: Usually not. Caustic drain cleaners can eat through a small soft blockage but do nothing to tree roots, collapsed pipes or heavy grease, and repeated use can damage older pipes and seals. If a blockage keeps returning, the cause needs to be found and cleared mechanically.
How do I know if tree roots are the cause?: Tell-tale signs are gurgling toilets, multiple drains slow at once, and blockages that return every few months, often worse in wet weather. The only way to confirm is a drain camera inspection to see the roots in the pipe.
Can I stop grease blockages myself?: Yes, largely. Never pour cooking fat or oil down the sink, wipe greasy pans with paper towel before washing, and run hot water through the kitchen drain after doing dishes. This prevents the fat setting hard inside the pipe.
Is a slow drain the same as a blocked drain?: A slow drain is an early warning that a blockage is forming. It is much easier and cheaper to clear at that stage than to wait until it is fully blocked and overflowing, so it is worth acting on a slow drain early.
How much does it cost to clear a recurring blockage in Sydney?: Clearing a blocked drain in Sydney is roughly $150 to $350 depending on severity and access, and a full drain camera inspection is around $200 to $400. Terry gives a fixed quote before starting any work.

Related services

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Terry's been sorting plumbing across Berala and Western Sydney since 1986. Call 0415 274 542 for a straight answer and a fixed price.

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NSW Licence L10959 · 40+ years experience