What Causes Drains to overflow and Backup?

06 September 2019

Sewage overflows are caused by issues with your plumbing system. Sewage will overflow when the wastewater is unable to flow through your sewer drains.

The most common reasons for sewage blockages:

Foreign matter:

 Grease, tree roots, food, hair and small objects can create a blocked sewer line. These blockages can stop the drain flowing, causing overflows.

Damaged pipes:

 Cracks appear due to age in clay sewer pipes. Dirt, tree roots, only need a small break to enter the pipes, creating a blockage that can overflow into your home.

Collapsed sewer lines: 

If a sewer drain has collapsed, water and waste will be unable to flow into the exit point at your property boundary. Some may escape into the ground, but the toilet paper and debris will build up and cause a blockage.

Tree root growing into the drain: 

Tree roots will look for water and nutrients, including waster that leak from sewer drains. If there are any cracks in the sewer drains, tree roots will grow through the cracks, making them open up and causing a backup.

Problems on the Municipality side of the boundary: 

 The city's sewer main is overwhelmed, due to bad weather, or repairs are being undertaken. Wastewater from your homes sewer drains cannot enter and are at risk from backing up. 

How Do You Know If Your Drains Are Blocked?

The smell of sewage coming up through your home's drains, is likely you have raw sewage backing up in your drains and into your home. Other sewage backups may include:

Noisy gurgling slow drains and toilets:

Blockages in pipes, especially at the lowest point in your home, the 

Plumbing fixtures may gurgle and bubble when other fixtures are being used. Raw sewage may overflow into your tub after you flush a toilet, or when you have a shower.

Also, Backups on lower levels can appear when you use water in upper areas of your home.

Who Fixes Your Sewage Blockage?

If the problem is on the municipal sewer line or system and causes the blockage in your home, the council is responsible for repairs.

 Problems with your home's sewer line, you are responsible for the repairs.

Your homeowner's insurance policy sometimes may cover damage and repairs.

You should always read your policy and confirm with your insurance company that you're covered for any drain damage. 

A blocked drain can happen anywhere where you have water.


Leading blocked drain plumber in Hobart, specializing in unblocking drains. We have the latest drain cleaning tools available for the biggest main sewer and storm water blocked drain emergency right down to a small blocked bathroom