5 Signs Your Drain Is Blocked (And When to Call a Plumber)

A blocked drain often starts with slow-draining water, unusual gurgling sounds or unpleasant smells coming from your sink, shower or toilet. Recognising these warning signs early can help you avoid wastewater backups, overflowing fixtures and more expensive plumbing repairs.

Most blocked drains don't happen overnight. Grease, hair, soap residue, food scraps and tree roots can gradually restrict water flow until the pipe becomes completely blocked.

If you've noticed something unusual with your household drains, here are five signs worth paying attention to.

1. Water Is Draining Slower Than Usual

One of the earliest signs of a blocked drain is water taking longer to disappear down your sink, shower or bathtub.

In kitchens, grease and food particles can accumulate inside pipes. Bathroom drains are more commonly affected by hair and soap residue.

If only one fixture is draining slowly, the blockage may be localised. However, if several fixtures are affected, the problem could be further down your drainage system.

2. You Hear Gurgling Sounds From Your Pipes

Drains should generally operate without noticeable bubbling or gurgling noises.

When a pipe becomes partially blocked, trapped air can create unusual sounds as wastewater moves through the restricted space.

You might hear gurgling from your kitchen sink after running the dishwasher or notice noises coming from your shower drain when another fixture is used.

Persistent gurgling is worth investigating, particularly when accompanied by slow drainage.

3. Unpleasant Smells Are Coming From Your Drains

A persistent smell coming from your sink or shower can indicate trapped organic material inside the drain.

Food scraps, grease and other debris can break down over time, producing unpleasant odours.

Sometimes the problem is relatively minor, such as residue near the drain opening. However, smells combined with slow drainage or wastewater backing up may indicate a deeper blockage.

If cleaning the accessible drain opening doesn't resolve the smell, a plumber can inspect the drainage system.

4. Water Backs Up Into Another Fixture

This is one of the more concerning signs of a blocked drain.

For example, you might notice water appearing in the shower when the washing machine drains, or the toilet water level changing when another fixture is used.

These symptoms can indicate a restriction in a shared drainage pipe rather than an isolated blockage.

Avoid repeatedly running water through affected fixtures, as this could increase the risk of an overflow.

A licensed plumber can identify the affected section and determine the appropriate solution.

5. Your Drain Keeps Blocking Again

A drain that repeatedly blocks may have an underlying issue that basic cleaning doesn't address.

Recurring blockages can be caused by accumulated grease, foreign objects, tree root intrusion or damaged pipes.

While a plunger may temporarily restore water flow, it won't necessarily remove the underlying cause.

Professional drain inspection, including CCTV drain cameras where appropriate, can help identify why the blockage keeps returning.

When Should You Call a Plumber for a Blocked Drain?

A minor, isolated blockage may respond to simple measures such as removing visible hair from a drain cover or using a plunger.

However, you should contact a licensed plumber if:

• Multiple drains are slow or blocked.

• Wastewater backs up into sinks, showers or toilets.

• Blockages keep returning.

• There are persistent gurgling sounds or unpleasant odours.

• You suspect tree roots or damaged underground pipes.

Avoid mixing chemical drain cleaners, as they can create safety hazards and may damage some plumbing materials.

For homeowners in Bentleigh and surrounding Melbourne suburbs, Watermates Plumbing can help diagnose and resolve drainage problems.

If you're dealing with recurring blockages or wastewater backups, explore our blocked drain plumbing services or contact Watermates Plumbing to arrange an inspection.

FAQs

Can a blocked drain clear itself?

Some minor obstructions may shift, but most blockages caused by grease, hair or tree roots won't reliably disappear on their own. Persistent symptoms should be investigated.

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

Common warning signs include multiple fixtures backing up, gurgling toilets and wastewater appearing in lower-level drains. These symptoms require prompt professional attention.

Should I use chemical drain cleaner for a blocked drain?

Chemical cleaners aren't always effective, particularly for tree roots or deeper obstructions. They can also pose safety risks, so mechanical clearing or professional inspection is often a better approach.