Dual flush toilet
toilet with two flush-volumes
In 1956 Charles Rothauser, a Hungarian immigrant, renamed his plastics company "Caroma" and began manufacturing bathroom products, including the world's first one-piece plastic toilet cistern (the cistern is the water tank above the toilet that stores the flush).
A traditional Australian way of saving water in a drought is to drop a housebrick into the cistern to reduce the volume of water in it. But in some cases you need that extra big flush!
In 1980, with $130 000 government assistance, Bruce Thompson of Caroma developed a cistern with two buttons and flush volumes (11.0 litres and 5.5 litres). This wasn't easy because the toilet bowl had to be redesigned to make sure less water could still remove the waste.
Thompson's Duoset cistern saved 32 000 litres of water a year per household when it was trialled in a small South Australian town. Caroma's success led to legislation in every state but NSW to make dual volume toilets compulsory in new buildings.
In 1994 the company completely redesigned the toilet in stylish porcelain in a modern 'organic shape'. Its 6 and 3 litre dual flush cistern and matching bowl halved the amount of water normally flushed away.
This combination of style and environmental awareness attracted attention in the tough European sanitaryware market and exports began soon after. The product is now shipped to more than 30 countries worldwide.
Who Did It?
Caroma Industries Ltd : R&D, design, manufacture
Government of South Australia : program support
Bruce Thompson : R&D manager
D McNeil : designer
'Towns get new loos, and didn't spend a penny'
The Australian, 21 June 1991.
Dual Flush Case Study
Association, Renew Issue 46, The Toilet and the Environment
Lessons. Toiletology 101
How toilets work