Public water system is a regulatory term used in the United States and Canada, referring to certain utilities and organizations providing drinking water.
The US Safe Drinking Water Act and derivative legislation define "public water system" as an entity that provides "water for human consumption through pipes or other constructed conveyances to at least 15 service connections or serves an average of at least 25 people for at least 60 days a year." The term "public" in "public water system" refers to the people drinking the water, not to the ownership of the system.
Some US states (e.g. New York) have varying definitions.
Over 286 million Americans get their tap water from a community water system. Eight percent of the community water systems—large municipal water systems—provide water to 82 percent of the US population.
The United States Environmental Protection Agency (EPA) has defined three types of public water systems:
Community Water System (CWS). A public water system that supplies water to the same population year-round.
Non-Transient Non-Community Water System (NTNCWS). A public water system that regularly supplies water to at least 25 of the same people at least six months per year. Some examples are schools, factories, office buildings, and hospitals which have their own water systems.
Transient Non-Community Water System (TNCWS). A public water system that provides water in a place such as a gas station or campground where people do not remain for long periods of time.
There are over 148,000 public water systems.
Approximately 52,000 CWS serve the majority of the U.S. population
Approximately 85,000 NTNCWS
Approximately 18,000 TNCWS.
EPA also classifies water systems according to the number of people they serve:
Very Small water systems serve 25-500 people
Small water systems serve 501-3,300 people
Medium water systems serve 3,301-10,000 people
Large water systems serve 10,001-100,000 people
Very Large water systems serve over 100,000 people.
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vignette|Formule développée du PFOA. vignette|Modèle 3D du PFOS. Les substances per- et polyfluoroalkylées (PFAS, de l'anglais per- and polyfluoroalkyl substances, que l'on prononce « pifasse »), autrefois aussi dénommées composés perfluorés, sont des composés organofluorés synthétiques comportant un ou plusieurs groupes fonctionnels alkyle per- ou polyfluorés. Elles contiennent donc au moins un groupement perfluoroalkyle, –CnF2n–. Il existe probablement entre 6 et 7 millions de PFAS.
The water industry provides drinking water and wastewater services (including sewage treatment) to residential, commercial, and industrial sectors of the economy. Typically public utilities operate water supply networks. The water industry does not include manufacturers and suppliers of bottled water, which is part of the beverage production and belongs to the food sector. The water industry includes water engineering, operations, water and wastewater plant construction, equipment supply and specialist water treatment chemicals, among others.
Un puits à eau est le résultat d'un terrassement vertical, mécanisé (par forage, havage, etc.) ou manuel, permettant l'exploitation d'une nappe d'eau souterraine, autrement dit un aquifère. L'eau peut être remontée au niveau du sol grâce à un seau ou une pompe, manuelle ou non. Les puits sont très divers, que ce soit par leur mode de creusement, leur profondeur, leur volume d'eau, ou leur équipement. Les premiers puits étaient probablement de simples trous mal protégés des éboulements et qui n'ont pas résisté au temps et ont disparu.
The removal of natural organic matter (NOM) using nanofiltration (NF) is increasingly becoming an option for drinking water treatment. Low molecular weight LMW organic compounds are nevertheless only partially retained by such membranes. Bacterial regrowth ...
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Copper is an essential trace element, the imbalances of which are associated with various pathological conditions, including cancer, albeit via largely undefined molecular and cellular mechanisms. Here we provide evidence that levels of bioavailable copper ...