If you are interested in the contents of your tap water you should visit your town hall and ask for the pamphlet (typically produced annually) or may be found on the town’s website too. It is also important to consider that water’s quality is tested before the water travels the municipal pipe system (and then your home’s pipes too, different issues depending on its age). Just ask the folks in Flint.
The environmental impact of excess bottled water consumption is well stated, however, the potential health impacts of either tap or bottled water consumption have not been considered.
Toxins in tap water include arsenic, aluminium, fluoride, trace amounts of discarded medications, chlorine and chlorine disinfection by-products. Arsenic is carcinogenic and the US Environmental Protection Agency (EPA) reduced the maximum level of arsenic permitted in drinking water from 50 to 10 µg/L. The US Natural Resources Defense Council estimates that as many as 56 million Americans living in 25 states drink water with arsenic at unsafe levels (www.nrdc.org/water/drinking/qarsenic.asp). Aluminium has been linked to Alzheimer´s disease and several other problems (1). Fluoride is a neurotoxin (2). Leaching of water through landfills which contain discarded medications results in their presence in drinking water (3), the effects of which remain undetermined. Chlorine and chlorine disinfection by-products are also present in tap water, both of which are toxic to mammalian physiology (4).
However, bottled water is not necessarily better, as much of it is actually bottled tap water. In addition, drinking any water from a plastic bottle is hazardous due to leaching of bisphenol A (BPA) which is a hormone disruptor (estrogen mimic) which has been associated with multiple health problems, including early puberty, risk of obesity and various cancers (5). There are additional problems with distilled, alkaline and ´vitamin´ waters.