Blocked Drains Australia: Causes, Costs and When to Call a Plumber

Published 2026-02-14 · 11 min read

Everything Australian homeowners need to know about blocked drains: causes, costs, DIY solutions, and when to call a licensed plumber.

Blocked Drains: Australia's Most Common Plumbing Problem

Blocked drains are the number one reason Australians call a plumber. From kitchen sinks clogged with grease to tree roots invading sewer lines, drain blockages range from simple five-minute fixes to complex jobs requiring specialised equipment. This guide helps you understand what causes blocked drains, how much it costs to fix them, what you can try yourself, and when you absolutely need a licensed plumber.

Every year, Australian plumbers attend hundreds of thousands of blocked drain callouts. The good news is that most blockages are preventable with the right habits and regular maintenance. Understanding the common causes and early warning signs helps you act before a slow drain becomes a full-blown emergency.

Common Causes of Blocked Drains in Australia

Different drains block for different reasons. Here are the most common causes Australian plumbers encounter:

Kitchen Drain Blockages

• Grease and fat: The number one cause of kitchen drain blockages. Cooking oil, butter, and meat fats solidify in pipes as they cool, gradually narrowing the pipe diameter until nothing can pass through.
• Food scraps: Rice, pasta, coffee grounds, and vegetable peels that slip past the sink strainer accumulate in the drain trap and beyond.
• Soap residue: Combined with grease, dish soap creates a thick, sticky layer inside pipes.

Bathroom Drain Blockages

• Hair: The primary culprit in bathroom drains. Hair combines with soap scum to create dense blockages that worsen over time.
• Soap and product residue: Shampoo, conditioner, and body wash residues coat pipe walls and catch hair and debris.
• Foreign objects: Razor caps, cotton buds, and small items that fall into drains.

Toilet Blockages

• Excessive toilet paper: Using too much paper in a single flush is the most common cause.
• Wet wipes: Despite being marketed as flushable, wet wipes do not break down like toilet paper and are a leading cause of sewer blockages across Australia.
• Sanitary products and nappies: These should never be flushed and commonly cause severe blockages.
• Children's toys: A surprisingly common cause of blocked toilets in family homes.

External Drain and Sewer Blockages

• Tree roots: The most common cause of external drain blockages in Australian homes. Tree roots seek moisture and can infiltrate even small cracks in sewer pipes, eventually filling the pipe entirely.
• Broken or collapsed pipes: Older clay or earthenware pipes deteriorate over time and can collapse, especially under driveways or in areas with heavy soil movement.
• Soil and debris: Stormwater drains often become blocked with leaves, dirt, and garden debris after heavy rain.

How Much Does It Cost to Clear a Blocked Drain?

Blocked drain costs depend on the severity of the blockage, the method needed to clear it, and whether it is during business hours or after-hours. Here is a detailed cost breakdown for 2026:

Service	Cost Range	When Used
Simple plunger clearing	$80 - $150	Minor blockages near the drain opening
Hand snake/drain snake	$100 - $200	Blockages within first few metres of pipe
Electric eel (drain machine)	$150 - $350	Moderate blockages deeper in the pipe
High-pressure water jetting	$250 - $600	Severe grease build-up, tree roots, stubborn blockages
CCTV drain camera inspection	$250 - $500	Diagnosing recurring blockages, inspecting pipe condition
Tree root cutting and removal	$300 - $800	Root intrusion into sewer or stormwater pipes
Blocked toilet clearing	$120 - $300	Toilet-specific blockages
Main sewer line clearing	$300 - $1,000	Blockage in the main sewer pipe from house to street
Pipe relining (no-dig repair)	$400 - $600 per metre	Permanent repair for cracked or root-damaged pipes

Compare drain clearing quotes from local plumbers using our Quote Comparison Tool.

Blocked Drain Costs by City

City	Basic Clearing	Water Jetting	CCTV Inspection
Sydney	$120 - $250	$300 - $650	$300 - $550
Melbourne	$100 - $230	$280 - $600	$280 - $500
Brisbane	$100 - $220	$250 - $550	$250 - $480
Perth	$110 - $240	$280 - $580	$280 - $500
Adelaide	$90 - $200	$240 - $520	$240 - $450

DIY Blocked Drain Fixes

Before calling a plumber, there are several safe methods you can try for minor drain blockages:

Method 1: Boiling Water

For minor grease blockages in kitchen sinks, slowly pour a full kettle of boiling water down the drain. The heat can melt and dislodge grease build-up. Repeat two to three times. Do not use this method on PVC pipes as boiling water can soften the joints.

Method 2: Plunger

A cup plunger (for sinks) or flange plunger (for toilets) can clear many minor blockages. Ensure there is enough water in the fixture to cover the plunger cup, then push and pull vigorously 15-20 times. The pressure and suction can dislodge blockages near the drain opening.

Method 3: Baking Soda and Vinegar

Pour half a cup of baking soda down the drain, followed by half a cup of white vinegar. Cover the drain and wait 30 minutes, then flush with hot water. This natural solution can break down mild organic blockages and deodorise your drains.

Method 4: Drain Snake

A basic hand-crank drain snake ($15-$30 from hardware stores) can reach blockages up to three metres into the pipe. Insert the snake into the drain, turn the handle to feed it through, and pull out debris. This works well for hair blockages in bathroom drains.

What Not to Do

• Avoid chemical drain cleaners: Products containing caustic soda or sulphuric acid can damage pipes (especially older ones), harm the environment, and create dangerous fumes. They rarely solve the underlying problem.
• Do not use a garden hose: Forcing water into a blocked drain without proper equipment can cause backflow and flooding.
• Do not disassemble pipes without experience: Incorrectly reassembled pipes will leak and may cause more damage.

When to Call a Blocked Drain Plumber

Call a licensed plumber for blocked drains when:

• DIY methods have not worked after two to three attempts
• Multiple drains are blocked simultaneously (indicates a main line blockage)
• Water is backing up from one fixture when you use another (e.g., toilet gurgles when you run the shower)
• There is a foul sewage smell from drains
• You notice sinkholes or wet patches in your yard (possible broken underground pipe)
• The blockage keeps recurring despite clearing
• You see sewage or waste water backing up — this is an emergency

For urgent drain blockages, use our Emergency Tradie Finder. For non-urgent work, post your job and receive competitive quotes from verified local plumbers.

CCTV Drain Camera Inspections

A CCTV drain inspection is one of the most valuable diagnostic tools in modern plumbing. A small waterproof camera is fed through your pipes, providing real-time video of the pipe interior. This reveals the exact cause and location of blockages, pipe damage, tree root intrusion, and pipe condition.

CCTV inspections are particularly valuable for:

• Diagnosing recurring blockages
• Pre-purchase property inspections (highly recommended before buying an older home)
• Identifying tree root intrusion before it causes a full blockage
• Locating damaged or collapsed pipes without excavation
• Verifying the condition of pipes after clearing

The typical cost of a CCTV drain inspection is $250-$500, which often includes a DVD or USB recording and a written report. This is money well spent when buying a property, as sewer line replacement can cost $5,000-$15,000.

Preventing Blocked Drains

Prevention is always cheaper than cure when it comes to blocked drains. Follow these practical tips to keep your drains flowing freely:

Kitchen Drains

• Never pour cooking oil, grease, or fat down the drain. Let it cool and dispose of it in the bin.
• Use a sink strainer to catch food scraps
• Run hot water down the drain for 30 seconds after washing greasy dishes
• Scrape plates thoroughly into the bin before washing

Bathroom Drains

• Install a hair catcher over shower and bath drains ($5-$10 from hardware stores)
• Clean hair catchers weekly
• Flush drains monthly with baking soda and hot water

Toilet

• Only flush toilet paper and human waste — nothing else
• Do not flush wet wipes, even those labelled flushable
• Use reasonable amounts of toilet paper per flush

External Drains

• Keep gutter and stormwater drains clear of leaves and debris
• Trim tree roots near sewer lines — or have a plumber inspect annually if you have large trees near your drainage
• Schedule an annual drain inspection if your home is over 30 years old

Use our Maintenance Calendar to set up regular reminders for drain maintenance. Taking a few minutes each month can save you hundreds in emergency drain clearing costs. Ready to find a local drain specialist? Browse verified plumbers in your area.

Frequently Asked Questions

How much does it cost to unblock a drain in Australia?

Blocked drain clearing costs in Australia range from $80 to $1,000 depending on the severity and method used. A simple plunger or hand snake job costs $80-$200, electric eel clearing costs $150-$350, high-pressure water jetting costs $250-$600, and main sewer line clearing costs $300-$1,000. A CCTV drain inspection to diagnose the problem costs $250-$500.

Can I unblock a drain myself?

Yes, many minor drain blockages can be cleared using DIY methods: boiling water for grease blockages, a plunger for toilet and sink blockages, baking soda and vinegar for mild organic build-up, or a hand-crank drain snake for hair blockages. However, if these methods do not work after two to three attempts, or if multiple drains are blocked simultaneously, you should call a licensed plumber as the blockage may be in the main sewer line.

What causes recurring blocked drains?

Recurring blocked drains are usually caused by an underlying structural issue: tree root intrusion into pipes, partially collapsed or damaged pipes, incorrect pipe fall (gradient), or a build-up of hard deposits like calcium. A CCTV drain camera inspection ($250-$500) is the best way to identify the root cause. Pipe relining is often the long-term fix, costing $400-$600 per metre but avoiding the need for excavation.

Should I use chemical drain cleaners?

No. Most plumbers advise against chemical drain cleaners. Products containing caustic soda or sulphuric acid can damage pipes (particularly older clay, PVC, and copper pipes), create dangerous fumes, and harm the environment when they enter the waterway. They also rarely fix the underlying cause of the blockage. A plunger, drain snake, or professional clearing is safer and more effective.

How do I know if my main sewer line is blocked?

Signs of a main sewer line blockage include: multiple fixtures draining slowly at the same time, gurgling sounds from toilets when you run other taps, water backing up from floor drains, foul sewage smells from drains, and wet or sunken patches in your yard above the sewer line. A main sewer blockage is more serious than a single fixture blockage and usually requires professional clearing with an electric eel or water jetter.

Frequently asked questions

How much does it cost to unblock a drain in Australia?

Blocked drain clearing costs in Australia range from $80 to $1,000 depending on the severity and method used. A simple plunger or hand snake job costs $80-$200, electric eel clearing costs $150-$350, high-pressure water jetting costs $250-$600, and main sewer line clearing costs $300-$1,000. A CCTV drain inspection to diagnose the problem costs $250-$500.

Can I unblock a drain myself?

Yes, many minor drain blockages can be cleared using DIY methods: boiling water for grease blockages, a plunger for toilet and sink blockages, baking soda and vinegar for mild organic build-up, or a hand-crank drain snake for hair blockages. However, if these methods do not work after two to three attempts, or if multiple drains are blocked simultaneously, you should call a licensed plumber as the blockage may be in the main sewer line.

What causes recurring blocked drains?

Recurring blocked drains are usually caused by an underlying structural issue: tree root intrusion into pipes, partially collapsed or damaged pipes, incorrect pipe fall (gradient), or a build-up of hard deposits like calcium. A CCTV drain camera inspection ($250-$500) is the best way to identify the root cause. Pipe relining is often the long-term fix, costing $400-$600 per metre but avoiding the need for excavation.

Should I use chemical drain cleaners?

No. Most plumbers advise against chemical drain cleaners. Products containing caustic soda or sulphuric acid can damage pipes (particularly older clay, PVC, and copper pipes), create dangerous fumes, and harm the environment when they enter the waterway. They also rarely fix the underlying cause of the blockage. A plunger, drain snake, or professional clearing is safer and more effective.

How do I know if my main sewer line is blocked?

Signs of a main sewer line blockage include: multiple fixtures draining slowly at the same time, gurgling sounds from toilets when you run other taps, water backing up from floor drains, foul sewage smells from drains, and wet or sunken patches in your yard above the sewer line. A main sewer blockage is more serious than a single fixture blockage and usually requires professional clearing with an electric eel or water jetter.