5 Common Causes of Drain Blockages and How to Avoid Them

Drain blockages are a common and frustrating problem in homes and businesses across New Zealand. A slow-draining sink, a clogged shower, or an overflowing toilet can disrupt daily life and lead to costly plumbing repairs. Understanding the most common causes of blocked drains can help homeowners prevent them before they become serious issues.

In this guide, we’ll explore the five most frequent causes of drain blockages and provide practical tips to avoid them. By following these preventive measures, you can keep your plumbing system in top shape and avoid unnecessary expenses.

1. Grease, Fat, and Oil Build-Up

Why It Causes Blockages:

Pouring cooking oil, grease, or fat down the drain is one of the leading causes of blockages. While these substances may be in liquid form when hot, they quickly cool and solidify inside the pipes. Over time, they create a thick, sticky coating that traps food particles and debris, leading to slow drainage and complete blockages.

Signs of a Grease Blockage:

• Water drains slowly from sinks.
• A foul smell comes from the kitchen sink.
• Gurgling sounds when water drains.

 

How to Avoid It:

• Never pour grease down the drain. Instead, let it cool and dispose of it in a sealed container in the rubbish.
• Use a grease trap or strainer to catch food particles before they enter the drain.
• Flush the drain with boiling water and dish soap weekly to break down small grease deposits.

 

DIY Fix for a Grease Blockage:

If your sink is draining slowly due to grease buildup, try pouring a mixture of baking soda and vinegar down the drain, followed by hot water. This can help break down some of the grease.

2. Hair and Soap Scum Accumulation

Why It Causes Blockages:

Bathroom drains are particularly prone to clogs caused by hair and soap scum. Hair strands can easily get caught in pipes, and soap scum acts as a binding agent, forming tough clumps that restrict water flow.

Signs of a Hair Blockage:

• Water drains slowly in the shower or bathtub.
• You notice pools of water around the drain.
• Bad odours from stagnant water.

How to Avoid It:

• Use a drain guard to catch hair before it enters the pipes.
• Clean the drain guard regularly to prevent buildup.
• Rinse drains with hot water and vinegar to dissolve soap scum.
• Brush hair before showering to reduce the amount that falls into the drain.

DIY Fix for a Hair Blockage:

A plunger or a drain snake can often remove hair clogs. If the blockage is severe, a homemade mixture of baking soda and vinegar can help dissolve soap buildup.

3. Food Scraps and Coffee Grounds

Why It Causes Blockages:

Many people assume that food scraps will wash away easily, but some types of food waste can cause serious blockages. Rice, pasta, eggshells, fibrous vegetables, and coffee grounds can all accumulate in pipes, creating stubborn clogs.

Signs of a Food Blockage:

• Water backs up in the kitchen sink.
• A rotting smell comes from the drain.
• Gurgling noises when draining water.

How to Avoid It:

• Scrape plates into the rubbish bin before washing dishes.
• Use a sink strainer to catch food scraps.
• Never pour coffee grounds down the drain—dispose of them in the compost or rubbish.

DIY Fix for a Food Blockage:

Try pouring boiling water and dish soap down the drain to break down food grease. If that doesn’t work, a plunger or a plumbing snake can help dislodge food debris.

4. Tree Roots Invading Pipes

Why It Causes Blockages:

Tree roots are a major cause of blocked drains in New Zealand, especially in older homes with clay or concrete pipes. Roots are naturally attracted to moisture and can grow into small cracks in underground pipes, expanding over time and causing severe blockages.

Signs of a Tree Root Blockage:

• Multiple drains clogging at the same time.
• A drop in water pressure.
• Frequent sewage backups or overflows.
• Gurgling sounds from toilets.

How to Avoid It:

• Plant trees away from plumbing lines. If you’re unsure of pipe locations, check with your local council or a plumber.
• Schedule regular CCTV drain inspections if you have large trees near your property.
• Use root inhibitors to prevent tree roots from growing into pipes.

Fixing a Tree Root Blockage:

If tree roots have invaded your pipes, hydro jetting or mechanical root cutting may be required. In severe cases, pipe replacement may be necessary.

5. Flushing Non-Flushable Items

Why It Causes Blockages:

Toilets are designed to handle human waste and toilet paper only. However, many people flush items like wipes, sanitary products, paper towels, cotton buds, and even nappies, which do not break down easily and can cause severe clogs.

Signs of a Toilet Blockage:

• The toilet flushes slowly or doesn’t flush at all.
• Water rises to the brim and drains slowly.
• A bubbling sound comes from the toilet.

How to Avoid It:

• Only flush toilet paper and waste. Even “flushable” wipes can cause problems.
• Place a small bin in the bathroom for non-flushable items.
• Educate family members and guests on proper toilet use.

DIY Fix for a Toilet Blockage:

A plunger is often the first tool to try. If that doesn’t work, a toilet auger or a drain snake can help break up the blockage.

General Tips for Preventing Drain Blockages

1. Regular Maintenance

• Flush drains with hot water weekly to prevent buildup.
• Use enzymatic drain cleaners to break down organic matter.
• Consider professional drain cleaning every 1–2 years.

2. Install Drain Covers

• Catch hair, food scraps, and debris before they enter the drain.
• Empty drain covers regularly.

3. Be Mindful of What Goes Down the Drain

• Avoid pouring oil, grease, and food waste into the sink.
• Only flush toilet paper and waste.

4. Keep an Eye on Your Drains

• Watch for early warning signs like slow drainage or gurgling noises.
• Act quickly if you suspect a blockage.

Conclusion

Blocked drains can be a hassle, but understanding their common causes and taking preventive measures can save you from expensive plumbing repairs. By keeping grease, hair, food scraps, tree roots, and non-flushable items out of your drains, you can ensure your plumbing system runs smoothly.

If you’re dealing with a stubborn drain blockage, DIY methods may work for minor clogs, but severe issues require professional help. Regular maintenance and proper waste disposal habits are key to keeping your drains clear and avoiding costly plumbing emergencies.

For expert drain unblocking services in Auckland, contact a trusted local plumber to ensure your plumbing system stays in top condition.