4 Common Causes Of Blocked Drains

Have your pipes started giving off a terrible odour? This could be the sign of blocked pipes. Read more for our 4 top tips on why this might be happening.
It’s never a nice feeling finding out your drains are blocked. The discovery itself is often far from a pleasant experience, too.
Blocked drains often announce themselves via a nasty smell, foul water backing up your sinkholes and toilets, and sometimes by causing a leak somewhere in the piping system.

Top 4 causes of blocked drains

What actually causes blocked drains? Here are the most common culprits in residential settings. Take steps to avoid these and you will go a long way to avoiding blockages altogether. If it is too late and you already have this issue in your home, get in touch with Go Assist's Blocked Drains specialists.


People are often surprised to hear that a major cause of blocked drains in houses is human hair, and most hair is shed when taking a shower or bath. But surely I don’t lose that much for it to cause a problem, I hear you say. Well, when you factor in a household of people and the hair they lose over time, it builds up to a surprising amount. And as fine as individual hair strands are, collectively they can tangle up quite substantially. Use a drain cover to stop stray hairs from getting into your pipework.

Fat and grease

We’ve all heard of the infamous ‘fatbergs’ that build up in public sewerage systems causing untold havoc. The same issue can also strike the drains in your home. The problem is if you regularly wash a lot of waste cooking fat and grease down the drain when you wash your pots, either from your sink or your dishwasher, over time this can stick to the insides of your pipework and build-up, obstructing water from getting through. Fats that are solid at room temperature (e.g. butter and margarine, animal fats) are more of an issue than cooking oil, which is usually liquid. The best remedy is to remove as much grease as possible before washing pots and pans, for example by heating them up and pouring off excess fat into a container for disposal in the bin.


Grease is actually only one part of the problem in the well-known ‘fatberg’ phenomenon. The other is the widespread disposal of non-degradable toiletry products down toilets. Wet wipes are the biggest culprit, and it is thought that fatbergs only really became an issue when sales accelerated sharply in the 2000s. Wet wipes and other toiletries provide a surface for grease to congeal on, helping it to build up into a worryingly large mass. But in your own drainage system, wet wipes are enough to block the outpipes from your toilet on their own. Sanitary products are even worse - just one can absorb enough water to swell and completely block a pipe, causing water to back up. There’s a good reason why you are told never to put anything other than paper down the toilet.

Leaves and dirt

Finally, a major cause of blockages originates outside your home rather than inside. While the waste system (i.e. the pipework from your toilets) is fully enclosed for obvious reasons, the ‘grey water’ system from sinks, washing machines, dishwashers and so on drains into an open gutter built into the exterior of the building. Water from your rain gutters on the roof also feeds into here. Leaves and dirt can easily be washed down from the roof and into the main drain line, or directly into the external gutter if it isn’t protected with a cover. It is a good idea to have your gutters cleaned out regularly, otherwise, leaves and dirt could eventually cause serious problems.

Fast reliable drain unblocking repairs  

If you are having problems with blocked drains in your home, we are here to help! Contact our plumbing services team today to find a local plumber who can unblock your domestic drains in no time!

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