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Common Causes Blocked Drains

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  • Posted date:
  • 13-08-2021
Common Causes Blocked Drains

Common Causes Blocked Drains

Clogged drains usually start as trivial problems that can rapidly escalate into major plumbing issues. Such clogging might lead to slow water drainage, flooding, corrosion and, in extreme cases, sewage backup, which could ultimately necessitate expensive repairs.

Preventing your drainage system from clogging begins with recognising the common culprits and taking the necessary steps to fix them. Below are the common causes of clogged drains, the necessary preventative measures and how professionals can fix your plumbing system.

Signs of Blocked Drains

Clogging is the main culprit of backup in your sewer line. Prevalent signs of clogged sewer lines include gurgling sound emanating from your drain system, bubbling water and backup in the tub when you flush your toilet. 

Sometimes, these signs will manifest in a single sink, tub or toilet, which indicates that there is a clog in that particular drain. However, when every single flush results in a backup, the chances are that your main sewer line is clogged. 

As much as clogging in your drain system is preventable through proper usage, some cases are inevitable. This is where professional unclogging services come in handy. Common Causes of Clogged Sewer Line Clogged sewer lines might result from human error or natural occurrences. 

The former comes in the form of wipes, hair, soap and hard to flush items like paper towels or sanitary pads. These result in obstructions that might ultimately lead to major clogs. 

Conversely, natural occurrences that lead to clogging include tree roots, which grow into your pipes and cause perforations or wrap around your sewer line and eventually crush it. 

This could happen even when your property lacks trees as roots from neighbouring yards can grow towards your sewer line. Preventing Drains from Clogging Drains always appear to clog at the worst times like when you have staying guests. They can lead to leaky ceilings, peeling walls, nasty odours or flooding, which could damage your electrical fitting. 

While you may not have the ability to prevent clogs entirely, you can take effective steps to reduce the likelihood of clogging in your drains. Such include hiring regular maintenance services from plumbing professionals. 

You may also commit to collecting grease and food waste to prevent them from going down the drain. Also, avoid the temptation to throw personal care products such as wipes into the toilet. You should also flush your drains regularly especially if you use low-pressure toilets and taps. 

It is also advisable to install pop stoppers or a screen mesh in your bathroom sink to catch hair before it reaches your drainage system. 

Also, sweeping away foliage and garden litter will prevent drain clogging by reducing the amount of waste that gets washed down into your drain. Clogging in drains is amongst the most dreaded plumbing issues encountered by most homeowners. 

Adopting preventative measures like regular plumbing maintenance go a long way in preventing this issue. However, you will want to call professional engineers when you experience clogging in your drains; these experts can easily reinstate the normal functioning of your system. 

London drain clearance professionals employ state of the art equipment like sewer cameras to determine the cause of the clogging and subsequently apply advanced techniques to alleviate the issue.

Common Causes Blocked Drains London

Common Causes of clogged drainage

No matter the contents of your drains, whether water or waste, the idea of a clog is always a distressing one. If these contents meet a blockage when travelling through your drains, it will redirect itself whichever way it can. 

This can lead to several issues, including backups or flooding. While some of these issues may only be minor and easily resolved through simple procedures, others may lead to expensive and large-scale repairs.

Tree roots

Tree roots are the number one cause of clogged or blocked water and sewerage pipes. 

Natural material will naturally be drawn to water sources, causing tree roots and plants to break through your drainage pipes. 

Drainage professionals say that the earliest sign that tree roots may be breaking into your drain system is hearing gurgling sounds emanating from them. 


Overloading your drainage system is also possible, no matter the size of your disposal system. 

This is especially common if your home runs on a septic disposal system that limits the amount of waste it can hold. 

Flushable wipes

Many municipal water services are beginning to warn people of the dangerous effects of using flushable wipes on their drainage systems. 

While these wipes are called "flushable", this merely means that they can physically fit into a drain, not that they are suitable for drainage systems. 

Feminine hygiene

Like flushable wipes, feminine hygiene and baby wipes and products are also a clogging danger and should not be flushed down the toilet. 

Again, these products do not break down in the water, and given that they often contain cotton, which is absorbent and attracts other clogging agents, they can easily clog your drains. 


Leaks are the bane of the plumber's existence. If the leak is located underground, this can lead to the soil around the pipes falling away, leading to sagging or breaking. 

Fat, oil and grease

Fats, oils and grease are some of the worst things you can pour down your drains. Drainage professionals are raising greater awareness about the need to keep fatty and oily substances out of your drains. 

Those working for commercial businesses receive dedicated training regarding what can and cannot be poured down drains. However, those in private settings such as their own homes may be unaware of these clogging dangers. 


Hair can gradually accumulate in your drains to the degree that it creates a limited flow or complete clog in your drain. 

While you cannot prevent all hair from going down your drains, using plughole screens and removing the hairs that you can get will go a long way. 

Cat litter

Along with food and other large, solid waste, you should dispose of cat litter appropriately and not pour it down your drains. 

Cat litter is mostly made of clay-based substances, which can form into a concrete-like material if it is constantly made wet and dry over and over again.

Pipe scale

Pipe scale is a natural deposit that can build up inside your drains. 

Typically, these deposits consist of calcium, magnesium and other metals dissolved in the water that pours through your pipes. 

This scale can build-up to the point where it reduces the flow through your pipes or even causes a complete clog.


You should never place large pieces of waste food down your drains. 

Drainage pipes are not designed to dispose of large, solid matter, and any food should be disposed of in the bin, not your kitchen sink. 

Food can often be sticky or tough to break down and form large clogs very easily. 

Undersized sewer pipes

Undersized pipes are also a key cause of clogging and blockages in drains. 

Unless you have been the sole owner of your property or overseen its construction yourself, it can be difficult to gather a complete history of the property's plumbing. 

The average size of domestic drainage pipes is 4 inches in diameter, but many contractors will install ones slightly larger to be safe. 


Pipes, especially those made out of clay, terra cotta, or significantly old ones, can all disintegrate. 

Drainage pipe joints can work loose, and soil can shift, leading to your pipes sagging and breaking down. 

All of this natural damage can lead to debris entering the system, ultimately leading to a clog.

Natural clogging

Natural matter, such as leaves, twigs or even rodents, can all work their way into your drain pipes and create a clog. 

Leaves are one of the most common drain-clogging materials, and if they work their way into underground pipes, it can be very difficult to detect any issues before it is too late to prevent damage.

Slope of the sewer 

Given that gravity is the main force behind drainage systems, the slope angle of your pipes is essential to the smooth flowing of your waste. 

Depending on your house and the terrain on which it is built, the angle of your pipes will differ. But it would help if you were sure that the slope is sufficient to take the waste away from your home.

Dropped Objects

Foreign objects such as soap, jewellery, children's toys, food and many more besides can all be dropped into your drains and form clogs. 

If you can help it, the only things you should place down your drains are water, human waste and toilet paper. 

Combinations of materials

Some materials can combine to form a considerable clogging risk. Materials such as shower gel, soaps, and detergents can clump together to form sticky drain blockages that limit water flow through your drains. 

Experts recommend that you only use soaps that do not contain phosphates or surfactants or use powerful drain cleaners to remove these blockages.

Combinations of materials blocking Drains London

If you require drain unblocking in London contact our expert today.