The British and Irish are Europe’s fastest at washing up, while the Turks are the cleanest but use most water, according to a German study released on Thursday.
Professor Rainer Stamminger of Bonn University tested 75 people from seven different countries to see if there were national differences in the way they performed the task, and how much water and energy they used.
Each of them was given some 140 plates, cups, glasses and other items which had been dirtied and left to dry for two hours so the dirt would harden.
The average washer-up took 90 minutes to complete the task. The British and Irish were fastest, taking just one hour and using 43 litres (quarts) of water.
The Turks and Spanish were the slowest, needing some 108 minutes to finish the job, with the Turks using 135 litres of water.
There was no discernible difference between the washing-up performances of men and women.
Stamminger said it was surprising how people washed the dishes in different ways. Some filled the basin with clean water only once, others four times.
The study, which is continuing until February, is co-financed by dishwashing machine manufacturers from a number of European countries.