Complete Guide to Blocked Sewer Lines

Complete Guide to Blocked Sewer Lines

Having any blocked drain is an issue. However, having a blocked sewer line is the worst type of all. Nothing is more important than a working plumbing system, and nothing is more detrimental to that than a blockage.

At iSpecialise, we understand how inconvenient and unpleasant having a blocked sewer line can be, which is why, we’ve decided to provide all the relevant information you need to handle such a problem.

Today, I will be looking at how blocked sewers occur, how to know if your sewer line is clogged, who’s responsible for fixing sewer problems, and if you can clear a blocked sewer yourself. I’ll also tell you why it’s best to call a professional licenced plumber if you suspect or know you have a blocked sewer.

So without further ado, let’s get into it.

How do blocked sewer lines occur

I covered how to identify a sewage problem briefly in last month’s article, ‘What to Do if You Have a Blocked Sewer/Wastewater Pipe’, but today, we will look at the causes of blocked sewer lines in more detail.

The important thing to understand about toilet waste is that it combines with greywater, that being, water that passes from your bathroom sinks, showers, tubs, and washing machines to form wastewater that runs through wastewater lines. Your wastewater also includes any food scraps, fats, oils and greases that pass through the kitchen sink.

The wastewater line connects to gally traps and private wastewater pipes that connect to the public wastewater network. If you have a blockage in a sewer line, it’s the same as having a blockage in your wastewater line. A blockage means your wastewater cannot clear into the public wastewater network, which can present all sorts of plumbing problems.

Initially, a blocked wastewater line will likely cause drains to drain slowly. Eventually, when the blockage consumes the entire diameter of the pipe, preventing wastewater from passing, it will cause drains to overflow. When drains overflow, the wastewater goes back up the line and overflows from your plumbing fixtures, which is something you want to avoid at all costs.

While one may assume a blocked sewer line results from too much toilet paper being flushed down the toilet, this is actually not the primary cause. The leading cause of a blocked sewer is tree root infiltration, which I looked at more closely a few weeks ago. There are many other reasons also, which we look at below.

  • Tree root infiltration – as mentioned, tree root infiltration is the leading cause of a blocked sewer line. It takes just a hairline crack in a pipe for tree roots to sniff out the nutrient-rich water source and infiltrate the line. As time continues to pass, the roots continue to grow until they engulf the line, consuming the entire diameter. In some cases, the roots will grow so large and strong that they cause the line to break
  • Stormwater overloading – During extreme wet weather, stormwater can enter the sewerage network, overloading it. The overload increased the chances of sewage backing up in the system, spilling into streets, parks, beaches and even into people’s homes.
  • Improper use of a toilet – a toilet is only designed to flush away our waste and toilet paper. If we use a toilet as a rubbish bin for hygiene, sanitary items, nappies, wet wipes etc., there’s a strong possibility that a sewer blockage will occur. Toilets don’t have the necessary force to push heavier items down a sewer line. They will likely become get stuck and cause a blockage.
  • Improper use of a garbage disposal unit – because sewerage and greywater are combined in a wastewater line, what you put down your kitchen sink also affects your sewer line. Pouring hot fats and oils down a drain can produce what we like to call “fat burgs” – a mass of grease, fats, and oils that solidifies when it hits the cool water in a pipe. This mass then sticks to other garbage, forming a bigger and bigger mass, which can eventually block a wastewater line.
  • Old sewer lines – sometimes blocked sewer lines happen purely because the pipe itself is old and deteriorated. They won’t last forever and eventually require maintenance, so they will crack and contribute to a blockage at some stage.

How to know your sewer line is blocked

There are a few ways to help to tell whether you have a sewage problem. As mentioned in the article ‘What to do if you have a blocked sewer pipe/wastewater drain’, there are a few common tell-tail signs of a sewer problem. These include your toilet making a gurgling noise when flushing or presenting rapid high water levels when being flushed, which are then slow to lower to the standard level after flushing, drains being slow to clear and drains overflowing. I recommend you read the article if any such issues are apparently in your home.

In addition to these issues, there are other ways to tell if your sewer line is blocked.

Unpleasant odour coming from your drains

One easy way to determine whether you may have a blockage in your sewer line is by smell. If you smell the scent of sewage emitting from your floor wastes, sinks, and other drains in and around your home, you likely have a blocked sewer line.

A working sewer line will carry the wastewater from your home into the public wastewater network, so it doesn’t linger to present such smells. However, if the link is blocked, then the wastewater cannot leave your wastewater drains and lingers, which you can therefore smell.

Water present in the sewer clean-out

Every home has a sewer clean-out, which is one of the most important parts of a plumbing system. A sewer clean-out is a capped section of the sewer line, which allow access to clear blockages. It’s where plumbers such as iSpecialise access the sewer line with a plumbing snake, auger or hydro jetter to clear a blockage.

If you have a blockage, there will be water present in the clean-out because, like above, the water cannot pass your wastewater drains to enter the public wastewater network.

If you’re not sure where to find your clean-out line, there are a few things to try. First, look at your home’s plot plan – it will have it marked out on the plan. If you don’t have your plot plan, you can walk around your property and look for it – it will be a small pipe with a cap on it that can be removed. If you’re unsure, it’s best to contact a plumber – we know what to look for and will be able to locate it with ease.

Multiple blocked drains

As mentioned, your toilet, kitchen sink, bath, shower etc., are all connected via wastewater pipes, so a blockage in the line will often affect multiple plumbing fixtures. For instance, your bathroom sink won’t be the only sink that’s slow to drain; all sinks will be—the same applies to blockages. If your kitchen sink is blocked, so too will be your laundry sink and bathroom basin. Because a toilet connects to the wastewater line, the blockage will affect all plumbing fixtures in your home.

Who is responsible for repairing a blocked sewer line?

Unfortunately, if there is a blockage in the wastewater line within your property boundaries, It is your responsibility to fix it. The Watecare website states, “You own and are responsible for maintaining all the pipes, fittings and devices on your side of the point of supply.

It is only if the blockage is outside your property and can be proved to be outside your property that the responsibility lies with your local council to repair.

Find out more about your responsibilities from the Watercare website.

Can you fix a blocked sewer yourself?

A toilet plunger isn’t going to clear a blocked sewer, but you can try to clear a clogged sewer line yourself. However, in most cases,  a professional licenced plumber is required.

If you would like to have a crack at clearing a blocked sewer line before you call iSpecialise, we suggest you try the following:

  • Remove the sewer clean-out cap – locate your sewer clean-out and remove the cap. Removing the cap will help release pressure in your system, which may help your system drain once again. However, be careful when removing the cap; any wastewater above the clean-out fitting will gush out as soon as you remove the cap due to the pressure within the line. So, remove the cap slowly, and if water does start to seep out, tighten the cap back up and call iSpecialise.
  • Manually clear the line – if you are a little handy and have some drainage experience, you can purchase a plumbers snack or auger to try and manually clear the blockage yourself. To do this, remove the cap from the clean-out line and feed the plumber’s snake/auger down the line till you can reach and free the blockage.
  • Use Chemicals – we don’t particularly recommend this option as it can cause more significant problems, but it is still an option you can try. If a tree root infiltration is the cause of your blocked sewer line, then you can try flushing copper sulphate down your toilet. Copper sulphate is a root-killing foam that will kill the tree root. However, this isn’t an instant solution- it takes time and is therefore not suitable for severe cases where overflow occurs. This may be helpful if you catch a blockage in its early stages, while your sinks are still able to drain but are doing so at a slow pace.

Why it’s best to call a plumber?

In most cases, it’s best to leave blocked sewers to professional licenced plumbers. The location of the blockage could be anywhere, and without the right equipment, you won’t know where it is or have the tools to clear it. Moreover, it may be more severe than a blockage; the line itself may be damaged, in which case, it will need repairing or replacing by a plumber anyway.

Plumbers, like iSpecialise, have cutting-edge equipment that provides effective and efficient clearing of sewer line blockages. Using a combination of a CCTV camera, plumbing snake, auger and hydro jetter, we can inspect the line to determine if it is just a blockage or a damaged pipe causing the blockage. We then take the right actions to resolve the issue. These tools irradicate any guesswork, locate the site and cause of the blockage with precision, and result in the quickest possible solution.

How we go about clearing blocked sewer lines

Blocked Drains Buckland

The first thing we do is inspect the clean-out line. If we can see a blockage, we can quickly free it using a plumbing snake or auger. If we can’t see the backup but see a clear indication of a blockage, we will use our CCTV camera to locate the blockage and inspect the site to ensure there is no additional damage to the pipe.

If there is no damage, we will use our Ridgid KJ5000 high-pressure water jetter, which sprays out an astonishing 5000pSi of water pressure to dislodge and clear the blockage.

If the CCTV camera shows the pipe to be damaged, we will know where in the line the damage is and will be able to quickly repair the damaged pipe while clearing the blockage.

Contact us today to get your blocked sewer line or wastewater line unclogged.


Having a blocked sewer line is one of the most inconvenient problems a home can ever have, and more often than not, they require urgent attention. Your toilet waste is connected to your greywater in wastewater lines, so if something happens with your sewer line, it can affect your home’s entire plumbing system.

To make a blocked sewer line a little less inconvenient, you want to be able to clear it before it completely blocks the pipe and causes overflow – no one wants raw sewerage and wastewater coming up their drains!

To know if you have a blocked sewer, look for slow draining sinks, unpleasant odours from drains, a gurgling toilet, water in your clean-out, and multiple blocked drains.

Unfortunately, if the blockage is on your property, you are responsible for all sewage maintenance and repairs, including clearing a clogged sewer or wastewater line. As such, many homeowners like to try to clear the blockage themselves. A few things to try including relieving pressure in the line by removing the clean-out cap, trying to manually clear the line with a plumber’s snake or an auger, or with chemicals. However, if these methods don’t help or you’d prefer not to get your hands dirty, then you’ll need to call a plumber such as iSpecialise.

iSpecialise are experts at unclogging blocked drains in East AucklandSouth Auckland and Hauraki Plains and would love to assist. If you suspect you have a blocked sewer or any problem with your sewer line, give us a call on 09-2322 895 or submit an online enquiry.

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