Septic Tank Backup – Common Causes & How to Fix it

Is your septic tank backed up?

Not sure What has caused this & What can you do to fix it?

In this guide you will learn:

  • Common reasons for a septic tank getting backed up,
  • Warning signs of a backed-up septic tank,
  • How to handle issues that arise from a Backed up septic tank.

Common Causes Of A Backed Up Septic Tank

There are a wide variety of reasons why your septic tank may be blocked up.

Blockages may be caused by one or more of the following:

1. Tree Roots

Throughout the years, trees in your gardens will grow both above and below the ground. I

f your septic tank is built too close to these trees, then the growth in their roots may cause them to intercept your septic tank’s pipes. If this happens, the growth of the roots can lead to some key issues.

Firstly, the tree roots may cause your tank’s pipes to burst, leading to sewage flowing out into your garden.

Another problem may be caused by the roots growing into the pipes.

If this happens, the roots themselves may cause a clog in the septic tank’s system.

These issues can be difficult to solve since tree roots can be surprisingly resilient and difficult to access.

2. Flooding/Heavy Rain

One of the most common causes of septic tank backups. After a period of sustained and heavy rainfall, the ground around your tank will be saturated.

If this happens, then the septic tank will be unable to pump out filtered wastewater.

This will obviously lead to your septic tank backing up.

While this may seem like a problem that will fix itself, it is not.

The saturated ground will mean that the tank will begin to fill up with wastewater it cannot get rid of.

This can cause issues to cascade.

After a flood or period of heavy rain, calling a professional is recommended if you are worried about your septic tank leaking.

3. Clogs

As mentioned when discussing the growth of tree roots, anything that could clog up septic tanks pipes will likely lead to the system backing up.

Clogging is caused by something getting into the system that cannot easily be broken down.

The name for such an item is a Non-Flushable Solid.

Some examples include:

  • Female Hygiene Products.
  • Nappies/Diapers.
  • Disposable Gloves.
  • Cotton Swabs.

Putting anything other than toilet paper down your toilet is cautioned against for this very reason.

4. Increased Use

If you have had visitors over recently, then the increased use of your toilets may cause additional strain on the system.

If your toilets get a lot of use, then your septic tank may struggle to keep up, which could lead to a blockage.

5. Chemical Exposure

Finally, exposure to certain chemicals may cause your septic tank to block up.

Certain bacteria live in the septic tank and help break down raw sewage.

While resilient, if exposed to a high amount of household chemicals, these bacteria can start to die.

Some examples of household chemicals that could harm these bacteria include bleach, drain cleaner, and similar disinfectants.

If this happens, sewage breakdown will occur more slowly (if at all), increasing the likelihood of blockages.

Warning Signs Of A Backed-Up Septic Tank

The best way to avoid a blocage is to detect it before it happens.

Some of the common signs that your septic tank may be blocked up include the following:

1. Wet and Overly Healthy Yard

One of the most obvious signs of a backed-up septic tank can be seen in your yard.

Look for two things in your yard:

(1) If your yard is excessively wet without reason. If there has not been a lot of rain and your yard is still wet, then it may be time to check your septic tank.

(2) If a part of your yard is looking very healthy. The sight of a particularly healthy piece of grass in the middle of otherwise normal patches is a telltale sign that your septic tank may be leaking.

The leaking sewage acts as fertilizer which causes this healthy look.

2. Bad Smells

The first sign most of us notice. If your yard begins to smell awful for no reason, it is best to have a look at your septic tank.

It may be leaking, backed-up, or overflowing, allowing sewage to leak out and produce an awful odor.

This is even more noticeable if your septic tank is in your homes basement.

If you notice a fould smell coming from your basement, this is a sign that the tank down there may be blocked up.

You should also know that foul odors in the basement may be more dangerous.

Certain gases, such as methene, can push oxygen out of the enclosed space.

This may cause suffocation if it is not dealt with immediately.

Therefore, if you smell something bad coming from your basement, you should call a tradesperson as soon as possible to deal with the issue.

3. Slow Draining Sinks

A more subtle sign of a backed-up septic tank is slow drainage in your sinks. Water drained from your sinks or toilets is brought to your septic tank.

If this draining process is taking longer than usual, this may be a sign that there is a blockage somewhere in the system that needs to be dealt with.

Backed up Septic Tank?

Call 844-488-0570 for a Risk Free estimate from a Licensed Sewage & Water Damage Specialist in your area.

We Can Help Deal with the Sewage Backup & Repair any Damage Caused.

How To Fix Septic Tank Backup

Many issues that affect a septic tank do require professional assistance.

However, here are some steps you can take yourself if you want to start the process yourself.

The first thing you should do is locate the blockage.

You can start by opening the tank up to see how much waste is inside.

Depending on how much sewage is within can tell you what sort of problem you are having:

  • If the volume is low, the issue is probably located in the pipes between your house and the tank.
  • Meanwhile, if the volume is high, the issue lies in the tank itself or the pipes running off from it.

The second step you should take is to check the switches. Occasionally a blockage may occur because the system has been turned off accidentally.

Turning these off and on again maybe all that is needed.

If these do not work, your best bet is to call in a professional.

Professionals have access to specific tools that can help remove pipes and any blockages that may be within them.

They can also make use of special cameras to identify any blockages within the pipes, meaning they might not need to be removed.

Dealing With Septic Tank Backup Smell

One of the most unpleasant parts of a backed-up septic tank is, of course, the smell. It can be rancid and make it difficult to enjoy the outdoors (or the indoors, if you have a septic tank in your basement).

There are a few things you can do to deal with this smell.

Firstly, an ounce of prevention is worth a pound of cure. As mentioned previously, keep an eye on what goes down your drains and toilets.

Certain products cannot be broken down by the correct bacteria in the septic tank. These products include:

  • Coffee Grounds.
  • Cigarette Butts.

Since the bacteria cannot break them down, these products can release a pungent smell over time.

Make sure that these products don’t go down your drains by throwing them in the trash instead.

However, if this problem is already present, one solution is to adjust the PH levels in your septic tank.

A tank with a PH level between 6.8 and 7.6 should not smell, all else being equal.

Just be sure that these chemicals are not harmful to the bacteria in the tank, as this could cause more problems in the future.

Septic Tank Backing Up After Being Pumped

If your septic tank is backed-up after being pumped, there may be a few issues. These could include:

  • Using too much water: If you use a lot of water, this could cause issues with your septic tank. As mentioned previously, decreasing your water usage can help address this problem.
  • Blockages in pipes: If there are blockages specifically in your pipes, pumping your septic tank may not stop your system from backing up. This topic has also been discussed in this piece.
  • High water levels: If there have been heavy rainfalls recently then your septic tank may backup, even if it has been pumped recently. 

Preventing Septic Tank Backups In Future

Once your septic tank has been fixed, there are a few things you can do to prevent a backup in the future. 

1. Keep an eye on what goes down your drains.

As mentioned previously, certain products cannot be broken down by the bacteria in your septic tank.

Products such as coffee grounds and plastics should not be thrown into your toilets or drains.

Doing so will help avoid backups in the future.

2. Pump your tank before busy times.

If you are planning on having a lot of people over, getting your tank pumped can help you avoid overloading the system.

3. Keep your pipes up to date.

Finally, if the pipes in your system are particularly old, getting them updated may be a good idea.

Older pipes may struggle to handle as much volume as newer pipes.

Therefore getting more modern pipes installed can help avoid your system backing up.

Septic Tank Backup Cost

Prices obviously vary depending on your location and the availability of tradespeople.

However, the average price of getting a septic tank backup fixed is between 600 and 1,750 dollars.

More extensive repairs will cost even more, with estimates going up to as much as 5,000 dollars for particularly catastrophic issues.

When To Call A Professional

The best time to call a professional is before the problems arise. Getting a qualified professional to check your septic tank once every two years is the best way to avoid any issues.

However, if your septic tank is actively leaking sewage or a foul odor, then you should contact a professional immediately as these problems cannot be left alone.

With all that in mind, if you don’t feel totally confident in completing repair work by yourself, the best thing to do is to contact a licensed professional.


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