Within the EU, water is extracted from surface and groundwater sources and treated to comply with EU drinking water standards under the Water Framework Directive and Drinking Water Directive. The water is then circulated through the drinking water distribution system (DWDS) to end users, during which time its quality may deteriorate. The rate and extent of DWDS water quality degradation is influenced by: background water chemistry and treatment including presence of a disinfectant residual like chlorine; the design of the network; the age and configuration of the pipe infrastructure; the hydraulic conditions of operation including customer demand patterns; maintenance activities like flushing; and procedures for repairs.
While all water utilities must comply with EU Water Framework Directive and Drinking Water Directive requirements for specified water contaminants, many features of operation are not dictated by these regulations such as choice of treatment processes, procedures for maintenance activities, and hydraulic operations of the DWDS. Each water utility has its own sets of national standards and utility-specific procedures, many of them traditionally passed on and not always based on scientific evidence. Some of these typical practices, like flushing, may improve water quality in certain cases but the potential also exists that these activities can impair drinking water quality, resulting in regulatory violations and even waterborne disease.
Across the water industry, it is not clear what practices are most successful at ensuring clean drinking water under different conditions. Furthermore, localised issues concerning infrastructure design, historic protocols and national regulation make it challenging to identify and implement best practices.
This project bridged the gap between science and practice, involving water utilities and researchers from multiple locations across Europe along with third-country expertise, to examine DWDS operational practices and use scientific research approaches to better understand the water quality impact of different interventions. The outcome will be improved knowledge and identification of best practices, with dissemination to a wide range of countries and water utilities, to ensure that Europe’s drinking water remains of the highest quality in the world.
The primary research aim of Wat-Qual was to understand the impacts of DWDS flushing, chlorination, and maintenance/repair on drinking water quality across the diversity of practice in Europe, bringing together scientific and practical approaches to identify and disseminate best practice guidance and tools.
