The expectation that tap water is safe has been sorely tested by the recent events in Flint, Michigan, where lead contamination has caused a public health emergency (1). Apart from contamination with heavy metals and other harmful substances, a key concern is the control of microbial contamination. To prevent microbial growth and protect consumers from pathogens from other sources, some countries, such as the United States, require the presence of residual disinfectant in drinking water. However, the presence of a disinfectant can lead to the formation of potentially carcinogenic disinfection byproducts, issues with corrosion, and complaints based on the fact that people dislike the taste of disinfectants in their water (2). The experience of several European countries shows that such residual disinfectants are not necessary as long as other appropriate safeguards are in place.

As the world increasingly faces water shortages, it is critical to develop realistic estimates of water consumption based on water-use activities rather than top-down imposed limits. This study quantifies the absolute basic consumption (ABC) of an individual, irrespective of water-use location or water source, with a focus on personal water-use activities rather than measured household consumption. A theoretical model to stochastically describe 21 personal water-use activities was developed, corresponding to lifestyle levels based upon Maslow's hierarchy of physiological needs. From this model, the expected value of ABC was 92 L/capita/day (LPCD) and includes restrictions on several everyday activities and thus would be better as a minimum target during stringent water restrictions. A more realistic expected value for non-wasteful, indoor-only water use was determined to be 175 LPCD. The results of this study serve as a useful benchmark to inform policy choices and efforts to conserve water without affecting health and wellbeing.

Water utilities face a variety of challenges in meeting future demands under climate uncertainty, addressing aging infrastructure, ensuring water quality, and reducing energy use. The agility of the utility to implement innovative solutions to these challenges depends upon a variety of factors including utility governance and culture, regulatory environment, condition and performance of water infrastructure, and funding mechanisms for system improvements. The consequences of failing to meet these challenges could include environmental degradation, public health risks, and reductions in the level of service customers have come to expect, all at a highly elevated price. Two different types of water utilities are compared in this context: privately owned companies (using UK water companies as examples) and publicly owned utilities (using US municipal utilities as examples). Examples of innovation in the water industry, in the US and UK as well as globally, provide insight into the key barriers and opportunities for change. The successful drivers of innovation in the water industry are shown to include: a supportive culture at the water utility; a regulatory regime that allows or even promotes innovation; the financial ability to undertake research and implement improvements; and crucially, the backing of the public. Ultimately, neither the municipal nor the private model is perfect but the best elements of these could be combined as the basis for an innovative water utility of the future. WIREs Water 2015, 2:301–313. doi: 10.1002/wat2.1082This article is categorized under: Engineering Water > Planning Water Human Water > Water Governance

An all pipes network model with stochastic drinking water demand patterns (bottom-up) was used to study the difference in residual chlorine predictions compared to a transport model with one demand pattern (top-down). The results showed that the demand model had a small effect in combination with bulk decay at constant temperature. The top-down model results in higher chlorine predictions, but not at all locations and not consistently throughout the day. Including wall decay is important but only at certain locations. The bottom-up approach can help clarify the residence time at the worst locations

Discoloured drinking water, caused by elevated concentrations of organic and inorganic particles, is unacceptable. It occurs due to accumulation and subsequent mobilisation of material from within drinking water distribution infrastructure. Discolouration is currently partially explained by either the theories of cohesive layers or gravitational sedimentation. It is proposed and shown here how the processes behind these two theories both occur and how to integrate them to better explain observed behaviour and inform operational interventions to reduce discolouration. Deficiencies in understanding regarding the process and factors that influence material accumulation are highlighted. Future research addressing these deficiencies will enable determination of long term sustainable management strategies balancing capital investment and operational maintenance to safeguard distribution of high quality drinking water.

Understanding the processes and interactions occurring within complex, ageing drinking water distribution systems is vital to ensuring the supply of safe drinking water.