What causes sewage backups in homes?

A sewage backup is sometimes the cause of flooding on our property. Floods can cause the sewage from sewer lines to move through the drain pipes and thus backing up in our houses. This backup causes damage that is difficult to recover from and involves an expensive repair. Additionally, it can also cause many health hazards. There are some major causes behind these sewage backups:


Collection of water in basements

The basement gets flooded due to the settling of soil in the adjacent side of the building which when not corrected makes the rainwater flow towards the same building and it goes further down to the outer part of the foundation wall. The water then seeps into the basement through the cracks in the floor slab and foundation wall. This happens particularly, in old buildings.

Additionally, the waterproof nature of the basement walls becomes deteriorated once the building starts to get older because the ground becomes saturated repeatedly due to heavy rain. Hence, the basement should be water-sealed and the drainage system should be enhanced to tackle such a problem.


If your home drainage system and the primary sewer line are clogged, sewage can start to back up in your home. For instance, if a toilet has a sewage backup, the entire drain connected to this toilet will be clogged. But if every bathtub and toilet of your house starts to create backflows, it can be due to the clogging of the primary sewer line. Clogs are typically grease, solid particles, or hair found in the drains.

Damaged or broken sewer lines

The pipes made in the past were of clay and cast iron which do not last long. Hence, these pipes can easily crack and break down as a result causing sewage to backup. Usually, plastic sewage pipes are used nowadays to tackle such a problem.

Tree roots

Sewage backups can also be caused due to tree roots. If the area above the sewer line has trees, their roots might cause damage to it. Even if the sewer line is not under a tree, the roots from the trees present in neighbouring gardens and yards might interfere. The tree roots generate holes in these pipes and create blockages. In addition to this, it can also blanket the sewer lines and then slowly crush it once they start to grow.

Blockage in the city sanitary main

A city sanitary main can go through the problem of blockage. If this blockage is not checked in time, a sewage backup can occur in our office or homes due to the sewage of the sanitary main. This happens as the sewage passes through the floor drains and straight into our property. Such a thing happens gradually and within this time you can call a plumber so that he can monitor the damage.

Heavy rainfall

The sewer lines have a defined capacity and if water more than its capacity is filled with it, major problems will be caused. This usually happens at the time of heavy rainfall when a large amount of water flows in the drains for a prolonged time. This excess water may come into the sewer line of your house creating sewage to back up.

So now you know exactly why sewage backups in our property. Tree roots, damaged sewer lines, basement flooding, heavy rainfall, blockage in the main sewer line, damaged and broken pipes, and clogging are the major reasons why the sewage backs up in your drainage system.

Taking the necessary steps to prevent sewage backups is recommended in order to prevent any loss or damage to property. You can always call a plumber to check up the sewage backup in your house.

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