The measurement of water consumption has become a priority, on the one hand because water is becoming scarcer with the effects of global warming and a constantly rising global consumption. If we take into account, moreover, the increase in the cost of water treatment, it is therefore essential to have control over the use of this essential resource.
As part of a project to collect and process water consumption data, it is essential to define Indicators, which will allow:
- To follow the evolution of consumption over time, and therefore to measure the impact of measures to rationalize this consumption
- To compare these consumptions compared to other similar actors, in order to allow to be located in a sector of activity
Principle of a water consumption indicator
Like Energy Performance Indicators, water consumption performance indicators are ratios between consumption and a factor that influences this consumption. Among these factors, for example: the number of people (occupants, employees), the surface (m2), the quantities of goods produced…
Here are some general water consumption indicators, which can help in the construction of more specific indicators.
Indicator of water consumption per capita in Europe
In Europe, in 2021, each inhabitant consumed an average of 124 liters of water per day. There are great variations between countries. In Belgium, for example, this consumption per inhabitant is around 90 liters per day, which is one of the best performances in Europe. Water consumption depends on many factors, such as the climate, consumption habits, or even the age of the water networks.
According to a study by the European Environment Agency, water losses on the network represent only a few percent in Germany, and up to 50% in Bulgaria!
Water consumption indicator by activity sector
Globally, 90% of fresh water is consumed by agriculture (65%) and industry (25%).
In Belgium (Wallonia), industry represents 22% of consumption – 36 million m3 per year) and agriculture 4% (7 million m3 per year). This overall consumption is divided between:
- Households and Tertiary: 73.5%
- Non-commercial: 5.4%
- Agriculture: 4.2%
- Industry and Construction: 16.9%
- Building: 2.3%
- Agri-food 4.6%
- Chemistry: 4.8%
- Metallurgy: 2.3%
- Non-metallic: 1.2%
- Manufacture of machinery and equipment: 1.1%
- Printing: 0.3%
- Other: 0.5%
Indicator of water consumption in the tertiary sector
It is very difficult to give general figures, as these consumptions vary according to geography.
In Brussels, the residential sector represents 73% of water consumption, according to Bruxelles Environnement. The tertiary sector is 23%. The biggest consumers in the tertiary sector are:
- Health: 18%
- Restaurants: 17%
- Stores (retail, wholesale): 14%
- Public administrations: 10%
- Education: 10%
According to a French study, consumption in offices follows the following indicators. These indicators are obviously highly dependent on the type of activity, the presence of air conditioning, etc.
- 40 L / day / employee
- 4L / m2 of office