Quality of drinking water sources under growing pressure

Drinking water in the Netherlands is produced from (bank filtration) groundwater and surface water. The quality of these drinking water sources determines the level of the technical effort that water utilities must make to treat the water to achieve drinking water quality. KWR has produced a picture of the condition of Dutch drinking water sources by examining the (mostly public) survey reports and scientific research, collecting the key information on the quality of the drinking water sources and presenting them conjointly. This report (in Dutch) shows that the drinking water sources are under severe pressure and that, for a number of reasons, their quality is deteriorating. This is at odds with Dutch and European agreements prohibiting the deterioration of drinking water sources. The drinking water utilities are therefore urging that early measures be taken.

Groundwater: constantly more substances and risks

Groundwater as a source for drinking water is situated at increasingly greater depths and is contaminated with more and more substances. This leads to a steady, long-term and probably irreversible deterioration of groundwater quality. The main culprits are nitrates, pesticides, old soil pollutants and salinisation. Moreover, there are indications that traces of industrial substances, and veterinary and human pharmaceuticals are present in groundwater on an increasingly bigger scale. New activities in the subsurface, such as geothermal energy production or cold-heat storage, also present risks for groundwater supplies.

Surface water: substances, salinisation, antibiotic resistance and climate change

Surface water is also facing more and more threats, and this pressure will probably only go on increasing into the future. Specifically, this mostly concerns pesticides, salinisation, pharmaceutical residues and emerging contaminants. In addition, it is becoming increasingly clear that microplastics, nanomaterials and antibiotic resistance could also present a threat. Climate change, too, will probably have a negative impact on water quality, among others, through higher levels of salinisation and the decreased dilution of contaminants as a consequence of lower river discharges.

Drinking water utilities and Vewin are concerned

KWR conducted this scientific research on a commission from the Dutch drinking water utilities and the association of Dutch water utilities (Vewin), who feel the study presents a worrying picture. Vewin has written that ‘time is running out for drinking water sources in the Netherlands’, and stresses that more measures to improve the quality of the sources are absolutely vital.