Reasons Why Your Septic Tank Smells - Proseptic

Reasons Why Your Septic Tank Smells

Septic tank smells - drain

Due to the nature of septic systems, it’s likely you will occasionally come across a few septic tank smells. This is because of the natural bacterial processes taking place within your septic tank. When fitted compliantly and running correctly, these smells should be very infrequent.

However, strong and unusual smells coming from your septic tank area is something you need to be very wary of, as it could indicate a more serious issue with the workings of your septic system. Whether the odours are coming from your bathroom, or from the actual area where the septic tank is installed, you need to stay vigilant about what the issue is and how you can fix it. 

In this blog, we detail some of the reasons why your septic tank smells and ways you can combat this. 

Anaerobic Bacteria 

Through the correct use of aerobic bacteria, your septic tank should do its job without a hitch. Aerobic bacteria are incredibly good at digesting waste – but when your tank does not have a sufficient oxygen supply, Aerobic bacteria transform into Anaerobic bacteria, which unfortunately has the opposite effect. The presence of Anaerobic bacteria results in a much slower digestion rate. 

Anaerobic bacteria’s slower digestion of waste will cause a build-up of solids (known as sludge), meaning your septic tank will be harbouring more waste and therefore creating more foul smells. 

The bacteria’s access to oxygen is an essential component of an effective septic tank process and will help to minimise those stenches. Make sure you’re aware of how your septic system operates in order to address these possible smells. 


When certain household items and chemicals enter the septic tank, like pet bathing products, it can cause a whole host of issues, including putrid odours. 

Because your tank is designed to only decompose human waste, the inclusion of these household products could easily result in blockages, overfilling and ultimately the production of unwanted smells.

It is essential and best practice to always avoid sending incompatible products down your drains, as you will only be hindering the productivity of your septic tank. If you’re unsure about which products and chemicals shouldn’t be flushed down your drains, check out our blog here.  

Blocked Soakaways 

Drains and soakaways are an integral part of the septic system process, and once they become blocked or damaged (even partially), they can become responsible for a number of other issues like the production of smelly odours. 

Soakaways in particular are only designed to deal with liquids, so anything which is remotely solid can cause your systems to become clogged and therefore resulting in soakaway failure. As your blocked soakaway harbours unclean waters for a prolonged period of time, it is very likely an unpleasant stench will arise as a consequence of that clogging. 

Of course, this is not the soakaway’s intended purpose and needs to be dealt with as soon as possible. To get no obligation advice from our expert team on soakaways, please contact us today.

Your septic tank needs a service 

When installed and running as they should, septic tanks are relatively low maintenance. To keep your septic tank in its best possible condition however, you need to ensure you are keeping on top of its maintenance with servicing

Whether this be high-power water jetting, or a regular inspection, a service could be the answer to your septic tank smell issues. Regular maintenance guarantees that your tank is diagnosed with the correct problems and can then be fixed by our professional team. 

If you fail to keep your septic tank maintained, you could potentially open it up to more damaging issues and therefore more expensive repairs/replacements.  

Does your septic tank smell?

It’s never a good idea to let a bad smell fester. If your septic tank is emitting unwanted smells, then get in touch with our team to discuss this issue and we can help you sort it out.

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