Flushing the toilet on water wastage

Flushing the toilet is something that most people do automatically without putting too much thought into it. But given that the average Brit flushes the toilet five times per day and that older toilets can use up to 9 litres of water per flush, perhaps this is something we should be taking more notice of.

According to these websites here, here and here, flushing toilets is the largest single use of a household’s indoor water consumption, making up roughly 30% of indoor water consumed.  The average family moving from a single flush to a lower-use dual-flush system could save 80 litres per day.  And on a very sobering note, “Many people in the world exist on 10 litres of water a day or less. We can use almost that amount in one flush of the toilet.”

I must admit that I myself don’t often think about flushing the toilet; but recently a sign in a public toilet made me think twice. I was at Federation Square, a building complex and public space in downtown Melbourne, to catch up with Bri Williams, an Australian-based consultant and fellow behavioural-science-enthusiast.  The toilets at Fed Square had a dual-flush system with the following sign above the flusher: 

half-flush and full-flush buttons at Fed Square public restrooms

Working at the RSA in the Social Brain Centre, we are often looking out for examples of tool that help with behaviour change.  So the design of these public toilets stood out for me as a way to help make water conservation easy, salient, and normal.

First, the dual flush system makes it easy to conserve water – at the push of a button, even.  No need to contemplate about whether to use the old saying “if it’s yellow let it mellow”...

Next, the request to save water is highly salient – the sign is placed immediately above the flush buttons, right at eye level.  You can’t miss it. This is important because the request happens at the time of the behaviour (known as a hot trigger, as opposed to a cold trigger which would ask for an action at some point in the future, decoupled from the time of the request).

And finally, the sign makes water conservation normal. By stating that toilets use rain water to flush the toilets, it shows the ‘user’ that the rest of Fed Square is committed to reducing water wastage.  Normalising a new behaviour – in this case water conservation - is an important component of successful behaviour change.

To find out more about the benefits of dual-flush toilets, visit the websites listed above, or even take “the ultimate dual flush toilet quiz” here (it is amazing and somewhat terrifying what you can find  googling “toilets”).  Big actions, such as building redesign to capture rainwater for practical use, are crucial to make a large impact on outcomes (pro-environmental and other). But changes that each one of us can make to small, frequent actions, such as flushing the toilet, all add up to have a large impact too.