Saving water in cities: Assessing policies for residential water demand management in four cities in Europe

Policies for water demand management (WDM) have evolved in recent decades as an important strategy to reduce water consumption in cities. The objective of this study is to identify what WDM policies have been most effective, based on the perspectives of water utilities and experts. To this end, four cities with a low per capita residential water usage were identified: Berlin, Copenhagen, Tallinn and Zaragoza. A mixed-methods approach, including a questionnaire for water utility officials, semi-structured interviews, and review of secondary data and information, was used to identify successful policies. Results show that residential consumption from 1995 to 2015 has reduced in all four cities, irrespective of which policies were perceived to be more or less effective, though savings have been larger for cities with a larger number of perceived effective policies. WDM policies rated as highest-impact were renovation and maintenance of networks, and campaigns for water-saving technologies, followed by universal installation of water meters, rapid leak detection, public awareness campaigns, and municipal regulations. Tariff reforms were mentioned as impactful only in one case. However, lowering the level of urban water use by too much may lead to technological and financial challenges for water utilities.