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Drain Blockage: Ten Common Causes of Blocked Drains

30th November 2022

 Nobody wants a blocked drain. Unfortunately, however, they are a familiar occurrence in domestic properties across the country. But what causes blocked drains? There isn’t one definitive answer, as several different factors – some more surprising than others – can lead to a blockage. We’re here to teach you about the ten most common causes of drain blockages.

Ten Common Causes of Blocked Drains:

Leaves and outdoor debris

This rings particularly true in the autumn and winter months, when wind and other moody weather cause leaves and other debris to be blown or washed into drains, causing blockages. A chaotic garden landscape and a neglected gutter can exacerbate the chances of this occurring, so it’s important to stay vigilant. To protect against outdoor debris, we recommend buying a drain guard to cover your drain.


We all have it and unfortunately, we all lose it. Hair is unquestionably one of the most common causes of drain blockages across the world. Our silky locks may seem harmless and soft, but when mixed with conditioner and shampoo, can create a slurry mess at the bottom of our drains and lead to a blockage, especially in showers. To remedy this, you can use commercial drain cleaner or invest in a hair catcher.

Poor Drain Installation

Incorrect installation of waste pipes can cause massive problems. It’s critical to be aware of who is installing your drains, making sure they aren’t an untrained or uninsured tradesperson. If you have been burned by bad installation, we offer a free 24/7 callout service for blocked drains.


Another common cause of drain blockage is soap – not the old-fashioned bars, but liquid soap. It may not seem like a problem, but we usually use more than we need and the excess sinks down the drain. When combined with hair and other waste liquids, you’ll likely be on your way to a blockage of some degree.

Oil, Grease and Fat

When washed down the sink after cooking, grease and fat are easily the most common cause of drain blockage. We are sad to say that many people simply aren’t aware of the damage this can do to their homes. “Fatbergs” is a phrase coined to describe the large lumps of fat that can clog sewers and cause major issues for water companies. When poured down the drain in tandem with hot oil, which solidifies, you have a recipe for disaster.

Food Remnants

Its 2022, many of us now have food waste bins in our home so that we can safely dispose of our leftovers and do our bit to support the environment. Remember not to put your pasta, rice and veg down the drain, as there is a strong chance of it leading to a drain blockage. Be careful!

Tree Roots Damaging Drains

Moving away from drain blockage causes that we can pin to human error, common causes of blocked outside drains can stem from natural phenomena. Tree root intrusions can have a devastating impact on your drainage systems. Small leaks and cracks encourage tree roots to make their way inside your plumbing and wreak havoc. Stay one step ahead by using CCTV to ensure your pipes are healthy.

Wet Wipes

We understand that wet wipes are often used for things you’d rather flush down the toilet and never see again. However, baby wipes can stick together and cause destruction within your piping systems.


This mainly refers to cotton wool buds, swabs and sanitary towels. In no situation should these items be flushed down the toilet. Instead, they should be thrown out with general household waste or recycling. A small bin placed inside shared bathrooms can be a good way of reminding people of this. Alternatively, think about putting a visual reminder on the wall above the toilet.

Coffee Grounds

When thinking about causes of blocked drains, this is one that we feel is often overlooked. Unfortunately, coffee grounds can cause as much damage as fat – for the same reasons. Coffee grounds tend to solidify and then harden, which inevitably leads to drain blockages.

Learn How to Clear Blocked Drains In Six Simple Steps By Checking Out Our Quick Guide

That finishes our deep dive into ten common causes of blocked drains. It’s vital to be mindful and hold an understanding of what could be causing you issues; it will save you money in the long term. At Cotswold drainage, we usually fix 90% all of blockages in the first hour.

Our team of independent drain care specialists would be more than happy to help identify the best solution for you. Contact us by calling 01386 882324 or send an email to This email address is being protected from spambots. You need JavaScript enabled to view it..