A blocked drain can start as a small inconvenience. Water takes a little longer to disappear, the sink begins to smell, or you hear an unusual gurgling sound. Leave the problem alone, however, and a minor blockage can eventually become a serious drainage issue.

But what causes blocked drains in the first place?

The answer isn’t always something obvious. Grease, hair and food waste can create blockages inside household pipes, while tree roots, damaged pipes and underground drainage problems can cause recurring blockages that keep coming back.

Understanding the common causes can help you prevent problems and know when it’s time to call a professional.

1. Hair and Soap Buildup

Bathroom drains are particularly vulnerable to hair and soap residue.

Hair can become caught inside the pipe and gradually collect soap, dirt and other debris. Over time, this reduces the space available for water to flow through.

You may first notice that your shower or bathroom sink is draining more slowly than normal.

Prevention tip: Use a drain strainer to catch hair before it enters the pipe and clean it regularly.

2. Grease and Cooking Fat

Pouring cooking oil, grease or fat down the kitchen sink is one of the common ways to create a blockage.

Although grease may be liquid when it goes down the drain, it can cool and stick to the inside of the pipe. Other food particles can then attach to the buildup, gradually restricting water flow.

Prevention tip: Allow cooking grease to cool and dispose of it in the appropriate waste rather than pouring it down the sink.

3. Food Scraps

Even small amounts of food can contribute to a kitchen drain blockage when they repeatedly enter the plumbing system.

Coffee grounds, rice, pasta, vegetable scraps and other food waste can accumulate or combine with grease already inside the pipe.

Prevention tip: Scrape plates into the bin and use a sink strainer to catch food particles.

4. Tree Roots Growing Into Pipes

Tree roots can be a much more serious cause of blocked drains.

Underground drainage pipes can develop small gaps or damaged joints. Roots naturally seek moisture and can grow into these openings. As they expand, they may restrict the flow of wastewater and trap other debris.

If a drain keeps blocking after it has been cleared, tree-root intrusion could be one possible cause.

A CCTV drain inspection can help locate problems inside underground pipes without immediately resorting to excavation. WTR Plumbing & Gas uses drain camera technology alongside drain-clearing equipment to investigate the cause of blockages.

5. Foreign Objects

Items that shouldn’t enter the drainage system can cause sudden blockages.

In bathrooms, excessive toilet paper or unsuitable items can restrict the pipe. In kitchens, objects or large amounts of food waste can cause similar problems.

Once an object becomes lodged, water may drain slowly or stop flowing altogether.

Prevention tip: Only flush suitable toilet waste and keep unwanted objects, wipes and household items out of your drains.

6. Dirt and Debris in Outdoor Drains

Outdoor drains and stormwater systems can collect leaves, soil, sticks and other debris.

During heavy rain, large amounts of water may enter the drainage system at once. If the drain is already partially restricted, water can back up around the property.

Regularly clearing visible leaves and debris around outdoor drainage points can help reduce the risk.

7. Damaged or Collapsed Pipes

Not every blocked drain is caused by something you’ve put down the sink or toilet.

Older drainage pipes can deteriorate over time. Cracks, collapsed sections, displaced joints or other damage can interfere with normal water flow and allow debris to accumulate.

This is one reason recurring blockages shouldn’t simply be treated as isolated incidents.

A camera inspection can provide a clearer view of the internal condition of accessible drainage pipes. WTR Plumbing & Gas describes its CCTV camera service as a non-invasive way to investigate drains, sewer lines and stormwater pipes, with equipment reaching up to 60 metres.

8. Excessive Mineral or Sludge Buildup

Depending on the plumbing system and what enters the pipes, deposits and sludge can gradually accumulate inside drainage lines.

As the buildup becomes thicker, the internal diameter of the pipe becomes smaller and water has less room to flow.

If your drains are becoming progressively slower rather than suddenly stopping, internal buildup could be contributing to the problem.

9. Recurring Drainage Problems

One of the biggest warning signs is a blockage that keeps coming back.

You might have the drain cleared, everything works normally for a while, and then the same problem returns.

That can indicate that the visible blockage isn’t the underlying cause. Tree roots, pipe damage, heavy buildup or a deeper obstruction may still be present.

Rather than repeatedly treating the symptom, identifying the cause can help determine the appropriate long-term solution.

How Can You Prevent Blocked Drains?

A few simple habits can help reduce the chance of drainage problems:

• Don’t pour cooking oil or grease down the sink.
• Use strainers in kitchen and bathroom drains.
• Keep food scraps out of sinks.
• Don’t flush unsuitable items down the toilet.
• Remove leaves and debris from outdoor drains.
• Pay attention to slow-draining sinks and showers.
• Don’t ignore recurring blockages.
• Arrange professional drain maintenance when problems repeatedly occur.

Prevention is generally easier when you deal with small warning signs before they develop into a major blockage.

When Should You Call a Plumber for a Blocked Drain?

A slow drain doesn’t always mean you have a serious plumbing problem. However, professional help is worth considering when:

• The drain is completely blocked.
• Several drains are affected at once.
• The blockage keeps returning.
• You notice sewage smells.
• Water backs up from another drain.
• You hear persistent gurgling.
• You suspect tree roots.
• You have an older drainage system.
• DIY methods haven’t resolved the problem.

WTR Plumbing & Gas provides blocked drain diagnosis and removal, using high-pressure water jetting to clear blockages and CCTV drain camera technology to help identify the underlying cause.

Why CCTV Drain Inspection Can Help

Simply clearing a blockage doesn’t necessarily explain why it happened.

A drain camera inspection allows a plumber to investigate the inside of the drainage system and look for potential causes such as tree roots, damage or other restrictions.

This can reduce guesswork and help determine what type of repair or cleaning may be appropriate.

For drainage, sewer and stormwater investigations, WTR Plumbing & Gas uses CCTV technology designed for non-invasive inspection, with a camera reach of up to 60 metres.

Need Help With a Blocked Drain?

If your drain is blocked, slow or repeatedly causing problems, getting the cause identified can save you from repeatedly dealing with the same issue.

WTR Plumbing & Gas blocked drain services can combine professional drain clearing with CCTV investigation where appropriate to identify the problem and determine a suitable solution.

Call WTR Plumbing & Gas on 0437 868 461 for assistance with blocked drains and drainage problems.