Can Heavy Rain Cause Septic Backup

Traditional septic tank systems can be beneficial in many ways – that is – before you encounter heavy rain.  Dealing with this problem consistently, you wonder, Can heavy rain cause septic backup?

Many people are puzzled about the cause of the septic backup in their homes.  It also keeps them wondering – If it’s rain, how can I prevent it?

Luckily, there is something you can do about it.

This article will help you spot the signs of heavy rain causing a septic backup.  Stay with us until the end as we’ll give you detailed instructions on how to solve it.

Can Heavy Rain Cause Septic Backup?


The answer to this question is short – yes, it can!  Unfortunately, this happens more often than you might think.

A septic tank system is made out of two main and mutually connected components.  The one is the underground tank, and the second one is a drain field.

The septic system is connected to your house by drain pipes that collect all of the wastewater from your home.  Any damage to the part of the system results in damage to the septic tank system as well.

A septic tank holds the wastewater and breaks it down before draining it into the drain field.  When a drain field is flooded, the effluent has nowhere to go, resulting in a septic backup.

Can a Heavy Rain Cause Septic Smell?


The answer to this question is also yes.  You probably noticed that a septic backup is followed by a sewer smell being present in your yard or even your house.  Why does this happen?

Normally, a septic tank would hold all of the potentially dangerous waste inside the tank until it breaks down.  When filtered out, the wastewater leaves the septic tank and flows into the drain field.

The wastewater kept in the septic tank usually goes hand-in-hand with the toxic sewage gases.  These gases are filtered out when the wastewater is adequately decomposed.

After heavy rains, hurricanes, or tropical storms, the drain leach is flooded.  This is a part of the septic system exposed to the outside factors.

Because of this, the septic backup is created, pushing the toxic sewer smell back into your house.

The same septic backup can even cause clogs in the drainage pipes, which can worsen the smell.

These sewer gases are not just awfully smelling, but they are also dangerous for your health!  Sewer gases can cause many health problems such as nausea, vomiting, headaches, and much more.  [1]

This is another reason why it’s important to act quickly, as we will show you how.

Why Does Septic Backup When It Rains?

After a heavy rain period, a drain field is often very saturated.  When the ground is saturated like this, it cannot collect any more water.

This is very problematic as virtually no water can flow out of the septic tank (as it normally would).

The next thing that happens is that the septic tank keeps collecting the wastewater from your home.  However, it gets overfilled very quickly, as it’s not being drained in that process.

This is how a septic backup is created.  With all of that wastewater having nowhere to go, it backs up into the systems and back into your home.

Signs of a Flooded Septic Tank


A heavy rain septic backup is easily noticeable once you know what signs to look for.  After learning this, you’ll be quick to react the next time you see some of these warning signs.

However, our best piece of advice is for you to work on preventing these symptoms in the first place.

  • Wet Drain Field and/or Lawn

If your lawn or drain field stays wet after the rain is over and all else is dry, this is a sign.  This shows a backup in your septic tank system, as the tank cannot properly release the wastewater after rain.

  • Sewer Smells

A backup in your sewer system can easily cause sewer smells to enter your house and even your basement.  You should work on identifying and removing sewer smells as soon as possible.

  • Slow Draining

When all of the water you use in your house has nowhere to go, you will soon notice slow draining.  This includes your bathroom and kitchen sinks, showers, and even toilets.

  • Gurgling Sounds

A septic backup is a kind of sewer system error that can cause the wastewater and gases to move differently than normal.  When gases move up your drain pipes and meet the water, this can cause gurgling sounds.

  • Water Backup

If the septic backup gets severe enough, it can cause the wastewater to travel back to your house.  The first sign of this is water appearing in your basement and floor drains. 

  • Changes During Rain

Lastly, pay attention if any of these signs appear more often during the heavy rains.  That is a clear indication of rain triggering a septic backup.

NOTE: If you’re still unsure if your septic tank is full, check out other warning signs of a full septic tank.

How to Keep Rainwater Out of Septic Tank

 To keep the rainwater out of the septic tank, it’s always advisable to:

  • Maintain Regular Septic Tank Checkup &
  • Be Prepared In Advance

There is only a limited amount of things you can do during and after the period of heavy rains.

If you’re caught in a heavy storm, it’s best to wait until it passes so you can do a tank repair.  But what if the heavy storm just happened and met you unprepared?

There are still some things you can do during the storm in order to keep the damage minimal:

  • Minimize the usage of water. The septic system is already flooded, so you want to flush the toilets and use the sinks only when really necessary.
  • Ventilate the house. The sewer smells have entered your house, so if you can, keep the house ventilated in order to release the toxic gases.
  • Avoid contact with contaminated waters. Avoid any contact with water backing up in your home because that water is highly contaminated and toxic. 

How to Prevent Rain Causing Septic Backup


When it comes to complicated situations like these, the best solution is always prevention.  Here are some tips for you to consider: 

  • Follow the weather forecast. This is especially important for areas like Texas or Florida, where hurricane seasons and strong weathers are frequent.  It’s easier to prepare for the storm when you know it’s coming.
  • Pump the septic tank beforehand. The septic tank needs to be pumped from time to time for maintenance.  [2]

However, it’s best to do so right before the storm so the tank can be in good shape and get through it easier.

Can heavy rain cause septic backup even if the tank is pumped?

Far less likely!

  • Avoid flushing toxic substances. To be more specific, avoid flushing non-flushable things like women’s hygiene products, kid’s toys, etc., as these can clog the system.

Also, avoid flushing medicine, as antibiotics are known to kill beneficial bacteria in the tank, disturbing its balance.  [3]

  • Clear out the rain gutters. Rain gutters can get clogged with debris.  You want to clean them out, so the rain has where to drain.
  • Redirect the runoff water. If possible, you should also direct the runoff water away from the drain field, so it doesn’t get flooded.
  • Switch off the pump. You may also choose to switch off the pump at the circuit box, but this is not always necessary.
  • Avoid driving over the drain field. Don’t drive across the drain field as this compacts the soil, and not enough water can get drained.  You also shouldn’t drive over the septic tank as this can damage the system due to pressure.
  • Seal all wastewater entry points. You should seal any areas that will allow wastewater to enter your home or rainwater to enter your septic tank. 

How to Repair Septic Backup After the Heavy Rain

After a storm period, there are certain things you should do and also avoid in order to seal the property damages.

  • Avoid pumping the tank. It’s best to wait for the flood to recede before you do this.  If your tank is pumped and full again, it’s because you didn’t wait for the flood to recede.
  • Reduce the usage of water. The drain field is already flooded, and wastewater has nowhere to go.  To avoid making this problem worse, use water only when really necessary.
  • Keep the kids and pets safe. The water backing up in the sewer system can be quite contaminated and toxic.  It’s best to keep away from touching it and keep your children and pets away from it as well.
  • Avoid using the well water. If you have no other choice, it’s best to boil this water before using it (especially before drinking).
  • Schedule a professional inspection. You shouldn’t wait to notice all of the signs mentioned in this article to call a professional service.  Seeing only 1 or 2 of these signs is enough to phone for help.

Other Causes of Septic Backup

If you doubt heavy rain is what triggers the septic backup, maybe there is something else that is causing it.  Chances are, both of these factors contribute to your septic tank working improperly.

Sudden greenery around your septic tank may indicate you’re dealing with a drain pipe leak.  A full septic tank can also overflow, causing the surrounding area to be flooded.

The wastewater or effluent that is released from the tank is beneficial to the growth of some plants.  It acts as a fertilizer!

However, you should be careful.  With a full septic tank, some unfiltered toxic water can also flood your yard.

Secondly, if you notice one of your kitchen or bathroom fixtures is frequently getting clogged, there lies your second factor.

You may be contributing to the septic backup by flushing some things that shouldn’t be flushed.  Avoid flushing too much grease, medicine, hair, or hygiene products other than toilet paper.

Flushing the stuff that doesn’t dissolve in water can take a huge toll on your septic tank.  It can also disturb the balance of the septic system.

A cracked sidewalk or pavement near your septic tank may indicate tree roots interfering with your septic system as well.  Dealing with tree roots can be tricky, as the roots can easily break the drain pipes and cause leaks.

Luckily, there are certain products available on the market that you can use to kill tree roots.  [4]

Above all, it’s important to know how to check septic tank is full.  If you know for sure that it’s full, then you know what next steps to take. 

Dangers of Septic Backup

The dangers of septic backup are very serious and should never be avoided.

Frequently avoiding the septic tank maintenance can introduce toxic gasses and water into your home.  This can have some serious negative impact on the health of your family.

For example, a full septic tank can release methane gasses into your home.  Methane gas can even displace the levels of oxygen, which can increase the risks of an explosion inside your house.  [5]

Another toxic gas released from a full septic tank is hydrogen sulfide.  This gas is so toxic that it can negatively impact the nervous system in humans and even lead to permanent eye damage.  [6]

Finally, a huge amount of bacteria can return from the tank into your home.  This bacteria is beneficial in the tank but dangerous in the home, as it can contaminate your drinking water.


Final Thoughts 

Now you know that heavy rains and storms can have a large impact on how your septic tank system functions.

This is mainly because the drain field gets flooded, and no wastewater can be released from the septic tank.  In turn, this can introduce harmful gasses and contaminated water inside your home.

You learned the best solution to this problem is prevention.  We highly advise you to apply the tips mentioned in this article in order to deal with septic backup before, during, and after the rain.

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