Blocked drains are a problem many of us deal with at home. No matter what kind of home you’re in, you’ve likely encountered a smelly, slimy drain at least once or twice. Drain blockages attract bacteria that colonise your plumbing and cause a foul odour to come out of the sink. This is why keeping drains clean is important for a smooth-running plumbing system. 

If blocked drains are a constant struggle for you, the only way to solve the problem is to get to the root cause. To do this, you’ll need to look at common causes of blocked drains and rule out any you’ve already addressed. Sometimes, a drain cleaning treatment is all that’s needed to dissolve the blockage and free up your pipes again. 

But sometimes, the problem is bigger than hair from the shower or food from the kitchen sink, and you’ll need a professional to diagnose the problem and ensure your house’s plumbing is safe, sturdy and functional.

Here are the five most common causes of blocked drains, from baby wipes to plumbing issues.

Cause 1: Kitchen paper, baby wipes and sanitary items

We see the signs on every public bathroom: ‘DO NOT FLUSH SANITARY ITEMS, BABY WIPES OR HAND TOWELS’. They’re everywhere, and most of us would logically assume that we’ve all taken it on board. 

But unfortunately, non-flushable items like kitchen paper, tampons, and baby wipes still frequently end up in drains, pipes and plumbing systems everywhere, and are one of the top causes of blocked drains. To avoid this, ensure you only flush toilet paper at your home.

Cause 2: Hair

Hair is probably the most common cause of blocked drains. To avoid drain blockages from hair, use gloves to remove any hair from the drain after every shower. A drain catcher will help with this. You can buy drain catchers in Bunnings and most home hardware or kitchen stores.

causes of blocked drains - grease and fat

Cause 3: Grease and fat

When you let fat and grease build up in your kitchen sink, it eventually congeals and hardens inside the pipes. The sticky mass can then block the drain, and will most likely become smelly due to a buildup of bacteria. 

To avoid this problem, throw grease into your composter or rubbish bin rather than pouring it down the sink.

Cause 4: Debris and dead leaves in the gutter

Blocked drains - leaves in gutters

Sometimes, the problem isn’t inside the house – it’s in the gutters and pipes outside. Roots from large trees seek water, and can cause damage to underground pipes that supply water to your house. A buildup of leaves in the gutters can also cause drain blockage.

To avoid this problem, monitor the growth of roots and keep trees well watered where possible to slow the expansion of roots, and clear debris from your gutters every month or two.


Reason 5: Poor quality plumbing materials or installation (the big one!)

Unfortunately, sometimes it’s not an issue you can fix yourself. If the plumbing work on your house was done with low quality supplies, not installed properly, or even if it’s just old, you will have problems with blocked drains again and again until the problem is fixed.


The best thing you can do to avoid faulty plumbing causing you trouble is arrange a Building and Pest Inspection before you buy a property. This way, you’ll know about any potential issues that may cause blocked drains for years to come before investing. You’ll also have more detailed information about the root cause of the problem to pass on to the plumber.

Visit our website to arrange a professional Building and Pest Inspection today!