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Domestic consumption of drinking water

Households use 69% of the water distributed in the Brussels Region. The average daily consumption of water per Brussels inhabitant amounted to 96 litres/day/inhabitant (2014). A new element since 2012: this consumption appears to be stabilising, whereas it had dropped regularly for a dozen or so years.

Importance of water consumption by households

The consumption of drinking water by Brussels households in 2014 accounted for 69% of total billed consumption in the Brussels Region.

For the same year, the mean consumption of household drinking water was 96.4 litres/day/Brussels resident. Split per municipality, the same averages fluctuate between 85 and 108 litres/resident/year.

It should be specified however that these estimates do not take into account the domestic consumption of Brussels inhabitants at their place of work. The actual domestic consumption of Brussels inhabitants is therefore higher.

Recent evolution and possible explanatory factors

The average water consumption of Brussels inhabitants continued to decrease significantly between 2002 and 2012 (-26 litres or a reduction of nearly 20%). But since 2012, it appears to have stabilised. Meanwhile, the population grew strongly between 2002 and 2012 before levelling out. This explains why overall consumption at the Regional level has remained stable over this period.

The factors likely to influence water consumption are multiple (population structure, household income, household size, household awareness, household electrical appliances which are frugal with water, whether a cistern is fitted or not, water pricing, etc.). For the Walloon Region, according to a study by Aquawal, the geographical disparities observed depend essentially on household income and the presence of rainwater cisterns: the higher the income and/or use of cisterns, the more consumption decreases.

Yet in the Brussels Region, the significant decrease in average domestic water consumption per inhabitant between 2002 and 2012 occurred even though household income increased overall between 2003 and 2012 (despite a period of stagnation between 2008 and 2010), undoubtedly related to the economic crisis (BISA, 2015). As for using rainwater, this remains marginal (see the chapter devoted to this at the end of this sheet). Household income and the use of rainwater do not therefore appear to be the reason for reduced water consumption in the Brussels context. Several hypotheses have been put forward to try to explain this decrease: the wider use of more water-saving equipment (showers, WC, dishwashers and washing machines, etc.), raised awareness of households, an increase in the price of water and the introduction in January 2005 of a pricing structure which increases according to the size of the consumption per person, etc. It is certain that the higher water bill over the period in question had an influence. Nevertheless, given that water is a basic necessity, its consumption only evolves moderately according to its price (weak elasticity): a 10% increase in the price of water results in a reduction of around 1% in consumption by Brussels households (cfr. draft of second water management plan).

Could the stabilising, which has seemed to be the new trend since 2012, mean that the average consumption achieved is approaching the "efficient consumption" level? i.e, that it satisfies minimum domestic needs without loss of well-being and without resorting to an alternative resource? The latter has actually been evaluated at 94 litres/day/inhabitant in Wallonia, during a study carried out among 3,000 households. This same study indicates that the consumption level falls to 72 litres/day/inhabitant as soon as an alternative resource (in 95% of cases, rainwater) is used for internal use (Key Indicators of the Walloon Environment, 2014).

Mains water consumption by households (2002-2014)
Sources: Vivaqua (water consumption according to meters) and Federal Public Service Economy, General Directorate Statistics and Economic information (National register, population on 1st January of the year)

According to data from BELGAQUA (2008), only 12% of water consumption by Brussels families is used for drinking, food and washing.

Household consumption of mains water
Source: BELGAQUA, 2008

Comparisons between the regions

In the Walloon and the Flemish Regions, domestic consumption of tap water is estimated to be 89.5 l/day/resident (2002 – Prevedello, 2006 in the “State of the Walloon Environment 2006-2007”) and 100 l/day/resident (2012 – Watermeter 2013). A possible explanation for the observed difference between the Brussels Region and the Walloon Region is the higher use of rain water: prudence is however called for in case of such comparisons because drawing up this type of statistics does not go without methodological difficulties. Moreover the issue of "statistically invisible" people's is greater in Brussels than in other regions (e.g. candidate refugees that are on the waiting register, undocumented persons, foreign diplomatic personnel and foreign nationals who work for international institutions).

According to the Belgian federation for the water sector (BELGAQUA), the national domestic consumption of drinking water per resident was in 2008 one of the lowest in Europe. The downward trend of the average consumption level of Brussels residents (-18.2% between 1996 and 2008) shows a good correlation with the consumption on the Belgian level (-23% for the same period according to Belgaqua).

Use of rainwater

According to the last general socio-economic survey in 2001, only 10% of Brussels families have a rainwater tank. Not only is this percentage substantially lower than in the Flemish (43%) and the Walloon Regions (31%), but also lower than in other large Belgian cities (32 % in Ghent, 34% in Charleroi). Furthermore, during the "Barometer of Brussels residents' awareness of environmental sensitivity" done in 2008 and 2012, 10 to 20% of the interviewees declared to use rainwater often or on a permanent base (compared to 11% in 2008). This figure varied in 2009 according to whether the people questioned lived in a house (31% of them said they used rainwater) or in an apartment 11%) and according to whether they were tenants (15%) or owners (18%).

In the Brussels Region, the use of rainwater is encouraged by regional and municipal premiums for the renovation or installation of a rainwater tank (in 2014, this applied to 10 municipalities). Nevertheless, a survey by Brussels Environment conducted with the municipalities indicated that only sporadic use is made of these premiums (see Environmental Impact Report for the first Water Management Plan, chapter 2.4, p.213-214). According to the regional data provided by Bruxelles Développement urbain, the premium applications for installing or renovating a rainwater tank represent merely 4% of the total number of files submitted (201 applications from a total of 4979 files between January 2008 and February 2011 and 125 applications from a total of 3469 dossiers in 2011 and 2012). A market study of rainwater tanks in the Brussels Region carried out in 2012 highlighted several obstacles when installing or renovating a tank: the low level of grants in relation to the cost of installation, the poor return on investment, the difficult access to and lack of space on land, but also the concern that citizens would have to pay a tax in the future. The stock of rainwater cisterns is difficult to estimate as no survey has been organised to date.

Otherwise, the sustainable use of mains water, particularly by households, is one of the intervention pillars of the first Water Management Plan (2009-2015) and the second plan which is currently being adopted (2016-2021).

Date de mise à jour: 29/10/2018

Study(ies) and report(s)

INTERTEK and RDC Environnement, September 2012. « Etude du marché des citernes d’eau de pluie en Région de Bruxelles-Capitale », study conducted in the framework of the project « Brussels Sustainable Economy (BSE) », 71 pp. Restricted (.pdf, in French only)

BELGIAN FEDERATION FOR THE WATER SECTOR (BELGAQUA), 2008. « LIVRE BLEU (Blue Book) - Tout ce que vous avez toujours voulu savoir sur l’eau potable et l’assainissement des eaux usées », Edition 2008, 76 pp. (.pdf, in French and Dutch only)

PREVEDELLO C., September 2006. « L’utilisation de l’eau de distribution en Région wallonne. Dossier scientifique réalisé dans le cadre de l’élaboration du Rapport analytique 2006-2007 sur l’état de l’environnement wallon. S.A AQUAWAL ». 110 pp. (.pdf, in French only)

VLAAMSE MILIEUMAATSCHAPPIJ (VMM), 2014. « Watermeter 2013, Drinkwaterproductie en –levering in cijfers », 92 pp. (.pdf, in Dutch only)