Proactive management of drinking-water safety and quality fits best with three essentials of drinking-water hygiene, which are 'avoid useless, optimize functional, and prevent harmful exposure'. Within this context, avoiding adverse effects on human health is of the highest regulatory albeit not only interest. Precautionary standards of drinking-water hygiene define it as pure and safe as possible by means of natural or technical barriers and by purification, filtration, and degradation of potentially noxious agents. Scientific standards for drinking-water aim at protecting on a long-term scale either human health, the distribution network/installations or the drinking water from tasting or smelling unusual/disgusting. Remedial standards help to protect humans for shorter than lifetime exposure. Functional surveillance of drinking-water safety and quality differentiates monitoring of raw water, finished water, and tap water. Wherever possible, protecting the natural purity of regional drinking-water resources by a multibarrier system is the most economic, sustainable, and reliable way to proceed. The (regulatory hardly functional) alternative would be to rely just on day-to-day surveillance for health compliance, correct technical treatment, and efficient disinfection. The question on how pure a high-quality drinking water should be is best solved on a regio-societal level. There, the esthetic concept 'purity of drinking water' is best realized by supporting the esthetic concept of an abundant regional aquatic nature by technical means to support regional water cycle(s). Bank filtration, artificial groundwater recharge, and the use of extensively cleaned and microbiologically safe wastewater in agriculture, all respecting the principle of ALARA (as low contamination as reasonably achievable), are effective means to back up such holistic concept.
Encyclopedia of Toxicology (Third Edition), 2014, Pages 227-235,