Quantity of water per flush

The figures provided for domestic water use are a combination of two data points: the average consumption linked to a particular use, often an average of several sources on the Internet (water consumption for a shower, a bath, a washing machine, etc.), and a comparison with the average proportion of domestic water used for that use in France (for example, 12% for laundry). For the toilet, this gives an average consumption of 9 litres of water, which varies according to whether or not there is a dual flush system.