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Sewer Backup in Basement

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  • 08-04-2021
Sewer Backup in Basement

If you experience a sewer backup in basement, you will need to get an expert to fix the problem fast.  Sewage water poses a severe health risk to you and your loved ones as it is filled with dangerous bacteria and bad odour. 

This can be nerve-racking particularly when water is already destroying your personal belongings in the basement. Learning how to handle sewage back up in your basement can minimise the cost of cleaning the basement. The process can be expensive if mismanaged because odours and dangerous bacteria can easily be left behind.

Establishing the cause of the problem is the first step towards getting a solution. It can be the waste from the sewer system that is causing the clogging or the local waste produced in your home. 

Usually, roots that have grown into the sewer line can cause severe blockages. A blockage can also occur if a portion of the sewer or drainage line is broken. Another source of a blockage are things flushed down the toilet and are stuck in the drain system. 

Your basement drain will back up when there is a clog.  Synchronously, the backing up will cause an overflow in the basement drain. At this point, the blockage will be quite evident.

sewer backup in basement London

Running a power snake with sharp cutting blades is essential to open the drain; although chemical products can also be used. It is prudent to use both in case the basement drain line is invaded by roots. The power snake can cut through the roots using the sharp cutting blades.

Preventing a Sewer Back-up in Basement

Preventing a Sewer Back-up in Basement -outdoor drains becoming clogged

Contaminated waste from hundreds of neighbours is more cumbrous and horrible compared to your waste which is easy to handle. When a huge amount of waste is backing up, it becomes a disaster. 

You will find your drainage backing up if the lowest drain in your basement, shower or toilet is lower than the temporarily raised water level. The system will be overwhelmed usually due to a high level of rainfall, and the overall water table will be raised temporarily. 

Installation of a gate is the only way to prevent your basement drain from backing up. Gates can be manual or automated. The automated solutions are the best and are called “Backflow Preventer” or "Backwater Valves”. On the other hand, manual gates can only be manually turned closed or manually inserted to keep the unwanted reverse flow out. To prevent your basement from back up; a Backwater Valve completely closes your main line. This will disconnect the flow from the sewer system outside. This occurs when it automatically senses water flowing in the wrong direction and back 

What Causes a Sewage Back-up in the Basement

So many things can cause sewage backups. It is so important that you watch what you are flushing down your toilet or putting down your drains, as it could cause major problems within your home or workplace. For example, you could have to close down your business due to a bad reputation or health risks.  If you would like some further advice, please don't hesitate to contact a professional today. 

Here is a list of the most common sewage backup causes:

Heavy Rainfall

Heavy rain is a huge problem when it comes to sewer backups. Too much rain can be hefty on sewer lines, and they may not be able to handle it. This means your property could be at risk of water damage. 

Tree Roots

When your trees start to grow long roots, you can get wrapped around your sewer line and grow into your pipe. This could cause your sewer line to be crushed. These can be trees that are near you, not just in your garden. 


You can get sewage backup in your basement when your main sewer line or drain pipes get clogged. If you have a sewage backup in your toilet, there will be a blockage in the drain connected to the toilet. However, if you have backflows in all your baths and toilets, you may have a clogged main sewer line or sump pump. Clogs are usually caused by foreign materials getting stuck in your drains, including grease down the drain, feminine products, paper towels, cooking oil and more.   

Damaged Sewer Lines  

Pipes used to be made out of cast iron and clay, which aren't very durable and don't have a long life span. The older the sewage system, the more likely it is to breakdown or crack. This will result in your basement getting flooded and also sewage backups. Now, sewage systems are made from plastic.

What are the Signs of Sewage Backups in Basements?

It is essential to watch out for signs of a sewage backup. Sewage backups can cause so many problems with your drains and pipes, and the problem will get worse and worse. This could mean you end up with a huge replacement bill. You can usually spot these signs easily, especially when you're flushing the toilet or running the tap. If you suspect a problem, but you aren't 100% sure, you should still contact a professional. 

Here is a list of the most common signs of a sewage backup in your basement. If you do spot any of these signs, please call a professional plumber immediately:

Foul Smells  

Since your pipes and drains carry wastewater and foul smells in the opposite direction to your house, if you can smell unusual or foul odours, then this means there may be a problem. 

Strange Fixture Issues

Does your washing machine and toilet have bubbles coming from them? Does your water back up in your toilets and sinks? These are all symptoms of a blockage in your sewer. 

Standing Water  

If the capped pipe in your sewer line has water leaking from it, this signifies that your sewage system is backed up.

Bubbling Toilets or Drains

If your wastewater isn't flowing through the pipes as it usually foes, then this is a sign that you have a backup in the basement. 

What to do if you have a Sewer Backup

Here is a step by step guide of what to do if you have a sewer backup:

Don’t use the Water Supply System

Make sure you don't flush the toilets and turn on any taps until the repair work has been completed.

Turn Off Electrical Power

You must turn off all the electricity where the flooding is, as if the wires get wet, this could be really dangerous.

Location of Main Circuit Breaker

If your main circuit breaker is located in your basement, then you need to be careful turning off your electrics.

Wear Protective Clothing

If you need to walk through the sewage water, you must wear PPE, including a face mask, eyeglasses, gloves and rubber boots.

Shut off the Valve

Next, you need to make sure you shut off your property's main water line, whether it is your home or office. 

Open Windows and Doors

It is important to let as much fresh air into your property as possible, so try and open your windows and doors.

Evacuate the Area

Firstly, it is important to evacuate the flooded areas, which can be harmful to people and pets. 


You need to notify your insurance company and your municipal authority as soon as possible.

Add Chlorine Bleach

You can use chlorine bleach to disinfect the area.

Steps for Cleaning up Raw Sewage in the Basement

DIY cleanups can be hazardous as sewage backups are risky when it comes to your health, and if the dirty water is near electricity, this can be even more dangerous. Below, you will see some helpful tips for cleaning up your sewage backup' however it is always important to get in touch with a professional to check it is safe.

Here are the main steps you need to take to clean up the raw sewage in your basement:


Wear protective gear, including a face mask, eye goggles, rubber boots and gloves


Identify the problem and where it is coming from, and how bad the problem is


Clear out everything from the room, and ensure to clean any debris


Use a wet vac to get rid of any dirty water


Scrub all the surfaces and rinse them with hot water


Sanitize the area using chlorine bleach


Check for mould around the flooded area


Check your sump pump


Clean yourself up


Dry the basement

Is Backed Up Sewage in the Basement Dangerous? 

Sewage backups in your basement can make you sick, as the water is contaminated with bacteria and diseases. If the water is near any electrical items in your home, this could cause electrocution, fires and more. Therefore, you need to think about the following factors before you start to clean up:

Is the size of the flooding too difficult to clean up on your own?

Are you already suffering from any existing health conditions?

Are you worried about the job being too dangerous?

If any of these are true for you, you must call a professional to clean up for you. 

If you do happen to spot any of the problems listed above, you need to contact a professional plumbing company that will handle the situation efficiently and effectively. Doing it yourself can be dangerous and can also make the problem worse if not done correctly. 

Are you experiencing a sewage backup or drain blockage in London? Have you tried every DIY method? If you require emergency drain unblocking in North London follow the link below for professional drain clearance services.