5 Causes of Blocked Drains

5 Causes of Blocked Drains

You need only look at the website of any plumbing company to see that Blocked Drains are one of their primary services. Indeed, the majority of our Auckland service calls are due to blocked drains. Whether it’s blocked stormwater or sewerage pipes or a blocked kitchen sink, regardless of the severity or location of the blockage, a blocked drain isn’t something that can be pushed aside or ignored.

If you have blocked drains, you’ll know about it! But how do they occur? And, more importantly, are there preventive measures to prevent drains from blocking? These are two questions that we at iSpecialise are frequently asked.

So let’s look at the causes of blocked drains and how you can prevent such blockages from occurring.

Grease & Cooking Oils

Grease & Cooking Oils

You may wonder how cooking oil or even grease can cause blocked drains, but they can, and they are one of the main culprits. Grease, fat and oils enter drains in a liquid form, but as they cool, they harden, sticking to the walls of the pipe along the way, building up until the passage is blocked.

How to Avoid: To prevent blocked drains from grease and cooking oils, avoid washing such fatty materials down the kitchen sink as much as possible. It’s better for your drains and better for the environment!


hair in drain

Unless you’re bald, you cannot prevent hair loss in the shower. It’s a natural process that is accelerated when we wash our hair. As our hair sheds, it falls to the shower base and inevitably, down the shower drain. When combined with greasy soaps and washing liquids, it binds to form an obstruction which blocks the drain.

How to Avoid: Brush your hair before taking a shower to remove loose hair and after showering, remove any hair that the floor waste catches.

Tree Roots

tree roots

Copyright Walter Siegmund

It doesn’t take much for a plant, dirt or tree root to invade a pipe and cause havoc. A small crack in an underground pipe is all it takes. Once a root occupies a pipe, it’s only a matter of time before the entire pipe is blocked.  I’ve seen some mammoth blockages with as much as 10 metres of piping blocked with tree roots.

How to Avoid: In many cases, there is nothing you can do to prevent this. However, it does pay to use services like “Dial before you Gig” to locate your stormwater and sewerage pipes. Knowing where they are, you can a) avoid planting large trees near them and b) avoid digging near them. Also, if you know you have old clay pipes, it may pay to have them replaces with PVC pipes.

Old Pipes

Plumbing Emergency

If your home is over 50 years old, then there’s a good chance that it has clay pipes for water and sewerage. Clay pipes were used in Australia till the early 1970s when they were replaced with PVC pipes. The clay pipes are susceptible to cracking, which in turn, welcomes tree roots and dirt, which cause blockages.

How to Avoid: See above

Excess Toilet Paper, Nappies & Sanitary Items

Excess Toilet Paper, Nappies & Sanitary Items

A toilet is not a garbage disposal unit. It is not designed to handle bulky items – it designed only for its intended use, and even then, it can become blocked. Excessive toilet paper, hand wipes, nappies and sanitary items are all common causes of blocked toilet drains, which are never pleasant.

How to Avoid: Only place toilet paper in a toilet, and not excessive amounts.


Blocked drains are one of the most common service calls for plumbers, and no home is immune to them. There are many causes of blocked drains, but the most common are grease and oil buildups, hair, tree roots, old pipes and excess toilet paper, nappies and sanitary items.

If you have a blocked drain in Auckland and need it cleared fast, call iSpecialise on 09-2322 895. We have specialist equipment to locate and remove the blockage swiftly and professionally.

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