Unclogging septic system. Cleaning and unblocking drain full of disposable wipes and other non biodegradable items.

What not to flush down the toilet if you have a septic tank!

If you have a new septic tank, or have bought a new home with its own sewage treatment plant, we’ve put together this quick guide on what not to flush down the toilet to keep your new system in top working order!

Stating the obvious…

Firstly, it’s important to understand what your new septic tank is for: sewage treatment. Whatever you flush down the toilet goes to the septic tank for treatment. So anything that isn’t sewage isn’t treatable and will accumulate inside the tank, interfere with the microbes, clog pipes or get stuck in the equipment.

Can babywipes be flushed?

Do not flush babywipes down the toilet unless they are biodegradable, the packaging will clearly state if they are. The risk to a sewage system is wipes getting caught in a pump impeller and causing it to fail. They also pose a risk of severe blockages to plumbing and pipework. The reason for this is very well explained by Kian Hennessy in his 2014 Young Scientist exhibit:

Kian Hennessy explains why not to flush wet wipes down the toilet.

What happens to your septic tank when you flush a wet wipe down the toilet

Flushing a wet wipe or similar down the toilet firstly slows the flow of water and waste through the pipework. Once inside the pipework it might get stuck and cause a blockage. Otherwise, it will eventually enter the septic tank where it will float about, never breaking down and taking up valuable space until it is time for desludging.

The same can be said for flushing tampons, sanitary towels, condoms or nappies down the toilet. It simply isn’t worth the risk.

Instead of flushing bulky, non biodegradable items down the toilet – bag and bin them instead. It is a little less convenient but it’s far, far less expensive than the cost of a fixing sewage back up or a replacing a sewage pump.

Can bleach be flushed?

Go easy on the bleach. A domestic septic system can deal with small, dilute amounts of bleach but using too much will harm the microorganisms inside the system that are responsible for cleaning the sewage. Wiping out these microorganisms with bleach defeats the purpose of having a sewage treatment plant, so try not to be too heavy handed with it.

Can used cooking oil be flushed?

Large quantities of used cooking oil should not be flushed down the toilet (or rinsed down the sink). Fats clog pipework, cause blockages and create sewage backups if not properly disposed of. A septic tank can cope with small amounts of grease diluted in soapy dishwater but dumping the contents of the deep fat fryer down the drain will cause problems. wikiHow have produced an excellent article on how to dispose of cooking oil if you’d like to know more.

What can I flush down the toilet if I don’t have a septic tank?

For those of us without a septic tank, i.e. connected to mains sewerage – the same applies. Everything we flush down the toilet ends up in the municipal sewage works and despite operating on a much larger scale, the same issues arise. Problems with sewerage works are an unpleasant situation for everyone involved and are largely avoidable if we simply pay a little more attention to what we flush down the toilet!

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