April 1, 2021

What To Do If Your Septic Tank Overflows

For those who have always lived in rural areas septic tanks are a normal part of everyday life. As they are underground, they are literally out of sight and out of mind.

That's until something goes wrong.

It's tricky to know what's really going on underground, and you might be blissfully unaware of any trouble brewing. That is until it shows itself above ground in the form of a septic tank overflow.

If you're unfortunate enough to have something go wrong, you could have a very smelly mess on your hands.

Then there's the question of what can you do? This largely depends on how bad your situation is. Hopefully, it's a quick fix and an empty will do the job, or it could be much bigger.

There are some common septic tank problems you should be aware of, but if it's too late following the below steps will point you down the right path and get your septic system properly working.

Step 1: Stop using water.

This may be a fairly obvious first step but it has to be done. At this point the more water you add to the system, the more it will leak. You will just be making the problem worse. So, the first thing to do is cut off the source.

If you can stop using water in your home completely,  that will be ideal. At the very least, you need to drastically reduce water usage, and limit your use to essentials only.

Cut out your regular shower or bath, use a friend's or neighbour's if needed, do laundry at a laundrette, and even let those dishes stack up until the problem is fixed. The same goes for toilets, only flush when necessary.

Step 2: Find the cause of the overflow.

There are a few factors that can cause a septic tank to overflow. Some of which you can control, some you can't. Your next step needs to be identifying what caused the overflow and inspecting the septic system properly.

For example, an overflow doesn't necessarily mean something is wrong with your tank.

Your septic tank will only have a certain level of capacity. Go past this level and it will overflow. The tank could be in tip-top condition but being flooded with too much water at once will only end one way.

So, consider which of these possible causes may be to blame for your overflowing septic tank.

  1. Too many people taking showers and using too much water in a short period of time.
  2. The same goes for laundry loads, have you done too many in quick succession?
  3. Has there been heavy rain? Could this have flooded your garden and caused water to leak from the leach field into the tank? Extra drain water or roof water can also cause overflow problems.
  4. When did you last have the tank emptied? Is it overdue?  It could be full of solid waste with little space left for liquids.
  5. You have a blockage. Check the content level of your septic tank. If the tank is low, you have an upstream blockage between the house and the tank. If the tank is full, you'll have a downstream problem. 
  6. Blocks in your septic system can also come from flushing things you shouldn't have. Sanitary products or disposable nappies for example. Is there anything recent you can think of that shouldn't have been flushed?
  7. Inspect your drainage field.  Check for any signs of damage here. However, it might be that it has failed due to age and needs replacing 

Step 3: Take Action. Or not...

Depending on what you think the cause could be will depend on what your next step is.

If you have had the tank emptied in the last year the overflow may be due to rain or overuse of water. In this case, you may be able to wait it out.

If you do, make sure to keep your water use to a minimum for a few days while the tank drains into the leach field. 

After a few days, if the problem persists you may have a clog or a leak in the tank itself.  At this point, it's best to call in the experts and have your tank emptied or inspected. Or both.

If you realise you're overdue an empty, and think the overflow is a result of a full tank get it emptied/pumped ASAP. A septic tank empty can remove the solid waste from the tank, leaving more room for liquids. Your tank will be back in working order in no time.

The recommended emptying intervals are every 3-5 years. That goes up to yearly if you have a waste disposal.

Until the problem is resolved, keep everyone out of the area where the smelly water is accumulating. It could contain harmful bacteria from the raw sewage. If you accidentally touch this water, wash your hands immediately.

If it's not your septic tank, it could be your drainage field.

If you've had your septic tank emptied and inspected and no issues were found, the next point of call is your drainage field.

Check for any signs of damage here. However, it might be that it has failed due to age and needs replacing. 

For example, there could be no damage to pipework, but a CCTV camera survey could show it is full of water and/or water is flowing back into the septic tank when it's emptied.

If this is the case it can be a sign that it's simply stopped working and needs to be replaced.

How to stop your septic tank from overflowing

There are many things that can go wrong with a septic tank system. Some of which are in your control, some aren't. It's important for septic tank owners to stay on top of maintenance and the overall health of the tank.

Below are some easy ways you can reduce the likelihood of your septic tank overflowing.

1. Be careful with what you flush

One of the most common reasons for septic tank overflows is materials being introduced that are detrimental to the septic system. 

Septic tanks are full of microorganisms that help break down the solids flushed into the tank. However, certain materials will kill these microorganisms. Without these solids being dealt with, your tank will fill prematurely.

Below are some items that should never enter septic tank systems:

  • Feminine hygiene products (tampons etc.)
  • Harsh household cleaners or chemicals (bleach etc.)
  • Nappies
  • Condoms
  • Coffee grounds
  • Plastics
  • Dryer sheets
  • Paper towels
  • Grease

The easiest way to avoid contaminating your septic tank is simple.

2. Keep an eye on those roots

If you have a few trees close to your septic tank this could also present a problem. Roots by their nature will seek water and are known for going through drain pipes to get it.

Tree roots can cause absolute carnage to your septic tank system, leading to expensive repairs.

Keep trees and deep-rooted landscaping at least thirty feet from your septic system. Definitely don't plant any new ones near your septic tank.

3. No Parking

You will want to avoid putting anything heavy on or near your septic tank and drainage field. Any weight could compact the soil and damage the system. 

This could damage the pipes and reduce drainage. Without adequate drainage, your system will overflow.

4. Keep on top of regular maintenance. 

It's easy to forget about this until it's too late but it's easy to fix. The best thing you can do is to understand your tank emptying intervals and keep a log of these. 

The most common schedule is every three to five years. This will vary by household though due to a number of factors.

You don't want your tank to reach capacity. Scum and solids will enter its drainage field, which will prevent proper drainage. Again, without adequate drainage, your system will overflow. 

The easiest way to avoid an overflowing septic tank is to stay on top of its regular maintenance.

5. Prepare for the parties and get-togethers

This is just to keep on the safe side and shouldn't really be a problem right now. If you're expecting friends and family around in the future, for Christmas, or any other events, it may be best to have your tank emptied before they come around. This is purely to take into account the increased usage of your system.

Closing thoughts

An overflowing septic tank is far from ideal, you need to act quickly to cut down water usage from your house and get the septic system looked at as quickly as possible, as well as inspecting your drainage field. Pump your septic tank if needed and stay on top of your emptying and maintenance schedule.

D-tox operates within the UK and has been running for 30 years and between all of our staff, we have a wealth of experience in dealing with septic tanks. If you are in need of a service or simply some friendly advice, call us on 0800 999 2260 or email us at info

Related Services

Septic Tank Emptying Service

Further Reading

Signs you septic tank needs emptying

How often should you empty a septic tank

What is a septic tank & how does one work

Christian Heritage

After joining the business at the end of its first year of trading, Christian has been involved in all aspects of the business.
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