We can thank the Australians for inventing dual flushing toilets.  In 1980 Bruce Thompson of Caroma Industries created the first dual flushing system enabling a half flush for liquid waste and a full flush for solid waste.

Whilst we do not like to think about these things or even less like to talk about them it is a necessary evil.  The fact that we have even been able to bring the loo into the home is a bit of a miracle really.

We are lucky as most of the Western world will know what a toilet is and how to use it.  There are still more than 2.3 million people world-wide without access to a toilet at all! More people have cell phones than toilets! 1 person in 3 without a toilet, there is still a long way to go.

Water shortage was the necessary factor that brought about the invention of dual flushing and the advent of water metering no doubt will make people think twice about even flushing the loo.

Traditional toilets used a fair amount of water and in areas where water can be scarce or very built up areas where water is also at a premium finding ways of cutting down on usage has to be for the greater good.

How does dual flush work

First we need to look at the traditional toilet and method of flushing which involves siphoning the waste. As a high volume is flushed into the toilet bowl it fills the siphon tube and pulls the waste and water into the drain.

Dual flush toilets have a larger trap-way which is a hole at the bottom of the bowl and a wash-down flushing system that pushes the waste down the drain. As there is no siphoning the system it needs less water for each flush and the larger diameter makes it easier for the waste to exit. This uses 68% less water with the combination of less flushing for liquid waste than a traditional low flow system.

The dual flush system has other advantages as well; it is far less likely to get clogged and may be less susceptible to lime-scale.

The disadvantages are that they are a little bit more expensive and it may take some getting used to as it will not be half full of water all the time.  In fact very little water will remain sitting in the toilet bowl. Sometimes the bowl will be marked and occasionally it may not flush all the waste in one flush. You may have to get used to cleaning the loo more often but you can throw the plunger away!


In Australia, Europe and Asia this system is replacing the traditional siphon system in many residential and commercial properties.  The US is fast catching on as well and here is why.

As US law (1994 the National Energy Policy Act) requires that new toilets sold use no more than 1.6 gallons per flush, new high efficiency toilets such as pressure-assist, gravity flush and dual flush are becoming a necessity.

Dual flushing may only use 1 gallon per flush so the advantage is obvious. It is a good idea to check with local and national incentives to switch over to using this new technology if you have an old washroom.

If you have a water meter you will already think twice before you even flush the toilet.  There are ways of blocking the amount of water going into the cistern but that is not an ideal solution.  When the time comes for refitting your washroom you will be looking at a completely different type of toilet.

When you think about how many times a day your toilet is flushed, on average each user will flush between 5 and 8 times a day and times that by the number in your house and then multiply by 5 gallons!  That is a lot of water going down the drain.

If you are thinking the same as me then what to think about this concept?