Toilet manufacturers are being urged to rethink the design of some dual flush buttons after new research showed that as many as eight in ten people are inadvertently wasting water and flushing money down the drain by pressing the wrong buttons.

Dual flush toilets were introduced to help people use less water in their own homes and in commercial premises.

By choosing a smaller flush over a longer one, around two litres of water are saved on every flush.

But a new study by WRAS (Water Regulations Approval Scheme) has found that many Brits are confused by the way some dual flush buttons are designed.

WRAS created 18 typical dual flush designs and asked 2,000 people to identify the short flush buttons. This study focused on buttons, but there are other ways to operate flushes, such as levers and infra-red.

Over half of respondents incorrectly identified the short flush in five out of the 18 designs. In the worst example, 81 per cent of respondents selected the wrong button.

Even the best designs were not 100% perfect. Every single one of the designs presented in the study confused at least some of the people who took part in the study.

WRAS Approvals Manager Ian Hughes said:

“Toilets use around 24 per cent of all the water used in a home. Dual flush toilets can help reduce the amount of water that gets wasted and they also save money for people who are on a water meter.

“However, our study shows that many of the designs used are confusing and we are calling on toilet manufacturers to make short flush options much more obvious for users.”

The research did highlight which types of button designs were more effective in explaining dual flush options:

  • Button designs are more effective if they have clear permanent markings to help

people identify the short flush.

  • Most people naturally expect a smaller button to mean a smaller flush, but the bigger button needs to be 1 ½ times bigger than the smaller one to achieve around 80 per cent recognition.
  • Some manufacturers use a larger button to select a short flush. This was the most confusing design for the people who took part in the study.

Ian Hughes continued:

“There are some good designs out there too, with manufacturers playing their part in helping people save water. 

“While some manufacturers include instructions, unless these are permanently marked on the WC, there is a risk that instructions or labels won’t be installed, meaning people miss out on the potential benefits of dual flush systems.”

The WRAS study coincides with World Toilet Day on Friday 19 November.

World Toilet Day is celebrated annually to inspire action to tackle the global sanitation crisis and help achieve Sustainable Development Goal 6 (SDG 6), which promises sanitation for all by 2030.