Water borne pollution is on the increase, probably due to several factors. Runoff from agricultural fields that might have been treated with chemical or organic fertilizers, drain down of surface water from properties that are uphill from private wells, these are both increasingly common.
Water makes an excellent vehicle for microscopic organisms to travel around, and of course as a society, we are using water as a means to move sewage products around as well, so the possibilities of cross-contamination are higher as the population increases.
City water is of course treated, and has to meet certain standards, and although these are occasionally ignored or bypassed with deadly results, as a general comment we can say that currently most city supplies tend to be safe to use, as they generally use ultraviolet light and ozoneation, as well as the old style filters, which are generally carbon.
It is probably a good idea to have a slight mistrust of the water supply, just to be on the safe side - after all, if the system fails the public, and results in sickness or worse, it is then too late.
Is good then to see that you can actually have control of the cleanliness of your own water supply, whatever the source, as alpine industries have systems to ensure water safety, as well as having air purification units as well that are filter free, as they use very little electricity, just about the same as a night light, and work by ionization of the particles suspended in the air, not filtering, this results in the attraction of the particles into a bunch, thus removing them from suspension in the air itself.
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