Does Adding Substances to Your Sewage System Really Work?

18 May 2015 by CSG



You may have heard of these additives that suppliers claim provide an effective alternative to getting your septic tank emptied regularly. But what a lot of you may be wondering is whether they really work, or whether they actually are a sustainable alternative to getting your septic tank emptied annually.


The additives in question are said to provide biological treatment for digesting organic waste. The producers behind the substances claim that they are made up of completely organic product and will not counteract the necessary bacteria already in your septic tank. They are said to reduce the need for repeated tank clear outs and soak-away repairs or replacements, naturally restore and maintain sewage systems, unclog drainage systems and remove odours.

To utilise them, it would require you to pour the liquid down your toilet at regular intervals. These intervals must be met otherwise this will lessen their effectiveness.


Researchers have stated that, for septic tanks, there’s really no need to add bacteria.  This is because, in the UK, the moderate climate means that the rate of anaerobic digestion is very slow, meaning that sewage systems, such as septic tanks, function more as a sedimentation tank than a bio-digester. What this means is that physical processes are much more important than biological ones, so there is no need to try to optimise the biological processes with additives. A healthy sewage system should already have all the micro-organisms it needs, and therefore you may be doing more harm than good by adding these substances to your sewage system in its long-term life-cycle.

Scientists advise that maintaining a healthy sewage system can be achieved by monitoring water usage and ensuring that it is emptied regularly in accordance with the rate at which it is filling up.


The Environment Agency states that you should have your septic tank or sewage treatment plant emptied every twelve months regardless of whether it is full or not. Therefore, with the cost of these additives at around £30-£50 a year, you will still need to arrange for annual sewage clearances to be made at an additional charge.

Finally, for the additives to take effect, it requires monthly maintenance work on your part, remembering to add them in order to ensure optimal effectiveness. Is it worth the hassle?

What do you think? Do additives really work? Leave your comments below.